Web Services Eventing (WS-Eventing)

1 Composable Architecture

By using the XML, SOAP [SOAP 1.1], [SOAP 1.2], and WSDL [WSDL 1.1] extensibility models, the Web service specifications (WS-*) are designed to be composed with each other to provide a rich set of tools to provide security in the Web services environment. This specification specifically relies on other Web service specifications to provide secure, reliable, and/or transacted message delivery and to express Web service and client policy.

2 Introduction

Web services often want to receive messages when events occur in other services and applications. A mechanism for registering interest is needed because the set of Web services interested in receiving such messages is often unknown in advance or will change over time. This specification defines a protocol for one Web service (called a "subscriber") to register interest (called a "subscription") with another Web service (called an "event source") in receiving messages about events (called "notifications"). The subscriber may manage the subscription by interacting with a Web service (called the "subscription manager") designated by the event source.

To improve robustness, a subscription may be leased by an event source to a subscriber, and the subscription expires over time. The subscription manager provides the ability for the subscriber to renew or cancel the subscription before it expires.

There are many mechanisms by which event sources may deliver events to event sinks. This specification provides an extensible way for subscribers to identify the delivery mechanism they prefer.

2.5 Example

Example 2-1 lists a hypothetical request to create a subscription for storm warnings.

Example 2-1: Hypothetical request to create a subscription

(01) <s12:Envelope
(02)     xmlns:s12="http://www.w3.org/2003/05/soap-envelope"
(03)     xmlns:wsa="http://www.w3.org/2005/08/addressing"
(04)     xmlns:wse="http://www.w3.org/2009/02/ws-evt"
(05)     xmlns:ew="http://www.example.com/warnings" >
(06)   <s12:Header>
(07)     <wsa:Action>
(08)       http://www.w3.org/2009/02/ws-evt/Subscribe
(09)     </wsa:Action>
(10)     <wsa:MessageID>
(11)       uuid:d7c5726b-de29-4313-b4d4-b3425b200839
(12)     </wsa:MessageID>
(13)     <wsa:ReplyTo>
(14)      <wsa:Address>http://www.example.com/MyEventSink</wsa:Address>
(15)     </wsa:ReplyTo>
(16)     <wsa:To>http://www.example.org/oceanwatch/EventSource</wsa:To>
(17)   </s12:Header>
(18)   <s12:Body>
(19)     <wse:Subscribe>
(20)       <wse:Delivery>
(21)         <wse:NotifyTo>
(22)           <wsa:Address>
(23)             http://www.example.com/MyEventSink/OnStormWarning
(24)           </wsa:Address>
(25)           <wsa:ReferenceParameters>
(26)             <ew:MySubscription>2597</ew:MySubscription>
(27)           </wsa:ReferenceParameters>
(28)         </wse:NotifyTo>
(29)       </wse:Delivery>
(30)     </wse:Subscribe>
(31)   </s12:Body>
(32) </s12:Envelope>

Lines (07-09) in Example 2-1 indicate the message is a request to create a subscription, and line (16) indicates that it is sent to a hypothetical event source of ocean events.

While lines (13-15) indicate where a reply should be sent, lines (20-29) indicate where and how notifications should be delivered; there is no requirement that these match. The absence of any extensions to the wse:Delivery or wse:NotifyTo elements indicates that notifications should be sent as SOAP messages to the endpoint described in lines (21-28). Note that lines (25-27) illustrate a typical pattern where the event sink lists a reference parameter (line 26) that identifies the subscription and will be included in each notification.

Example 2-2 lists a hypothetical response to the request in Example 2-1.

Example 2-2: Hypothetical response to a subscribe request

(01) <s12:Envelope
(02)     xmlns:s12="http://www.w3.org/2003/05/soap-envelope"
(03)     xmlns:wsa="http://www.w3.org/2005/08/addressing"
(04)     xmlns:wse="http://www.w3.org/2009/02/ws-evt"
(05)     xmlns:ow="http://www.example.org/oceanwatch" >
(06)   <s12:Header>
(07)     <wsa:Action>
(08)       http://www.w3.org/2009/02/ws-evt/SubscribeResponse
(09)     </wsa:Action>
(10)     <wsa:RelatesTo>
(11)       uuid:d7c5726b-de29-4313-b4d4-b3425b200839
(12)     </wsa:RelatesTo>
(13)     <wsa:To>http://www.example.com/MyEventSink</wsa:To>
(14)   </s12:Header>
(15)   <s12:Body>
(16)     <wse:SubscribeResponse>
(17)       <wse:SubscriptionManager>
(18)         <wsa:Address>
(19)           http://www.example.org/oceanwatch/SubscriptionManager
(20)         </wsa:Address>
(21)         <wsa:ReferenceParameters>
(22)           <ow:MyId>
(23)             28
(24)           </ow:MyId>
(25)         </wsa:ReferenceParameters>
(26)       </wse:SubscriptionManager>
(27)       <wse:Expires>P0Y0M0DT30H0M0S</wse:Expires>
(28)     </wse:SubscribeResponse>
(29)   </s12:Body>
(30) </s12:Envelope>

Lines (07-09) in Example 2-2 indicate this message is a response to a request to create a subscription, and lines (10-12) indicate that it is a response to the request in Example 2-1. lines (17-26) provide the subscription manager EPR for this subscription, and line (27) indicates the subscription will expire in 30 hours unless renewed.

3 Notations and Terminology

This section specifies the notations, namespaces, and terminology used in this specification.

3.1 Notational Conventions

The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119].

This specification uses the following syntax to define normative outlines for messages:

The syntax appears as an XML instance, but values in italics indicate data types instead of values.
Characters are appended to elements and attributes to indicate cardinality:
- "?" (0 or 1)
- "*" (0 or more)
- "+" (1 or more)
The character "|" is used to indicate a choice between alternatives.
The characters "(" and ")" are used to indicate that contained items are to be treated as a group with respect to cardinality or choice.
The characters "[" and "]" are used to call out references and property names.
Ellipsis (i.e. "...") indicate a point of extensibility.
XML namespace prefixes (see Table 3-1) are used to indicate the namespace of the element being defined.

In addition to Message Information Header properties [WS-Addressing], this specification uses the following properties to define messages:

[Headers]: Unordered message headers.
[Action]: The value to be used for the wsa:Action URI.
[Body]: A message body.

These properties bind to a SOAP Envelope as follows:

<s:Envelope>
  <s:Header>
    [Headers]
    <wsa:Action>[Action]</wsa:Action>
    ...
  </s:Header>
  <s:Body>[Body]</s:Body>
</s:Envelope>

3.2 Considerations on the Use of Extensibility Points

The elements defined in this specification MAY be extended at the points indicated by their outlines and schema. Implementations MAY add child elements and/or attributes at the indicated extension points but MUST NOT contradict the semantics of the parent and/or owner, respectively. If a receiver does not recognize an extension, the receiver SHOULD ignore that extension. Senders MAY indicate the presence of an extension that has to be understood through the use of a corresponding SOAP Header with a soap:mustUnderstand attribute with the value "1".

Extension elements and attributes MUST NOT use the Web Services Eventing namespace URI.

3.3 XML Namespaces

The XML namespace URI that MUST be used by implementations of this specification is:

http://www.w3.org/2009/02/ws-evt

Table 3-1 lists XML namespaces that are used in this specification. The choice of any namespace prefix is arbitrary and not semantically significant.

Table 3-1: Prefixes and XML namespaces used in this specification
Prefix	XML Namespace	Specification(s)
s	(Either SOAP 1.1 or 1.2)	(Either SOAP 1.1 or 1.2)
s11	http://schemas.xmlsoap.org/soap/envelope/	SOAP 1.1 [SOAP 1.1]
s12	http://www.w3.org/2003/05/soap-envelope	SOAP 1.2 [SOAP 1.2]
wsdl	http://schemas.xmlsoap.org/wsdl/	WSDL [WSDL 1.1]
wsa	http://www.w3.org/2005/08/addressing	WS-Addressing [WS-Addressing]
wse	http://www.w3.org/2009/02/ws-evt	This specification
xs	http://www.w3.org/2001/XMLSchema	XML Schema [XML Schema, Part 1], [XML Schema, Part 2]

The working group intends to update the value of the Web Services Eventing namespace URI each time a new version of this document is published until such time that the document reaches Candidate Recommendation status. Once it has reached Candidate Recommendation status, the working group intends to maintain the value of the Web Services Eventing namespace URI that was assigned in the Candidate Recommendation unless significant changes are made that impact the implementation or break post-CR implementations of the specification. Also see http://www.w3.org/2001/tag/doc/namespaceState.html and http://www.w3.org/2005/07/13-nsuri .

3.4 Terminology

Event Source: A Web service that sends notifications and accepts requests to create subscriptions.
Event Sink: A Web service that receives notifications.
Notification: A one-way message sent to indicate that an event, or events, have occurred.
Subscriber: A Web service that sends requests to create, renew, and/or delete subscriptions.
Subscription Manager: A Web service that accepts requests to manage, get the status of, renew, and/or delete subscriptions on behalf of an event source.

3.5 Compliance

An implementation is not compliant with this specification if it fails to satisfy one or more of the MUST or REQUIRED level requirements defined herein. A SOAP Node MUST NOT use the XML namespace identifier for this specification (listed in 3.3 XML Namespaces) within SOAP Envelopes unless it is compliant with this specification.

Normative text within this specification takes precedence over the XML Schema and WSDL descriptions, which in turn take precedence over outlines, which in turn take precedence over examples.

All messages defined by this specification MUST be sent to a Web service that is addressable by an EPR (see [WS-Addressing]).

4 Subscription Messages

To create, renew, and delete subscriptions, subscribers send request messages to event sources and subscription managers.

When an event source accepts a request to create a subscription, it typically does so for a given amount of time, although an event source may accept an indefinite subscription with no time-based expiration. If the subscription manager accepts a renewal request, it updates that amount of time. During that time, notifications are delivered by the event source to the requested event sink. An event source may support filtering to limit notifications that are delivered to the event sink; if it does, and a subscribe request contains a filter, the event source sends only notifications that match the requested filter. The event source sends notifications until one of the following happens: the subscription manager accepts an unsubscribe request for the subscription; the subscription expires without being renewed; or the event source cancels the subscription prematurely. In this last case, the event source makes a best effort to indicate why the subscription ended.

In the absence of reliable messaging at the application layer (e.g. [WS-ReliableMessaging]), messages defined herein are delivered using the quality of service of the underlying transport(s) and on a best-effort basis at the application layer.

4.1 Subscribe

To create a subscription, a subscriber sends a request message of the following form to an event source:

[Action]
  http://www.w3.org/2009/02/ws-evt/Subscribe

[Body]
  <wse:Subscribe ...>
    <wse:EndTo> endpoint-reference </wse:EndTo> ?
    <wse:Delivery ...> xs:any* </wse:Delivery>
    <wse:Format Name="xs:anyURI"? > xs:any* </wse:Format> ?
    <wse:Expires> (xs:dateTime | xs:duration) </wse:Expires> ?
    <wse:Filter Dialect="xs:anyURI"? ...> xs:any* </wse:Filter> ?
    xs:any*
  </wse:Subscribe>

The following describes additional, normative constraints on the outline listed above:

[Body]/wse:Subscribe/wse:EndTo

Where to send a SubscriptionEnd message if the subscription is terminated unexpectedly. (See 4.5 Subscription End.) If present, this element MUST be of type wsa:EndpointReferenceType. Default is not to send this message. The endpoint to which the EndTo EPR refers MUST support the SubcriptionEndPortType portType.

Note, subscribers wishing to correlate SubscriptionEnd messages with the subscription to which they apply MAY wish to add a distinguishing reference parameter to the EndTo EPR.

[Body]/wse:Subscribe/wse:Delivery

This element contains the information necessary to convey notification messages from the event source to the event sink in a manner required by the subscriber. This element MUST contain at least one child element.

[Body]/wse:Subscribe/wse:Delivery/wse:NotifyTo

This specification defines one OPTIONAL element, wse:NotifyTo, to be used as a child of the wse:Delivery element. When present this element indicates that notifications MUST be sent to the EndpointReference identified by this element.

[Body]/wse:Subscribe/wse:Format

This optional element contains the delivery format to be used for notification messages sent in relation to this subscription. Implied value is "http://www.w3.org/2009/02/ws-evt/DeliveryFormats/Unwrap", which indicates that unwrapped delivery should be used. See Section 2.3 Notification Formats for details.

If the event source does not support the requested delivery format, the request MUST generate a wse:DeliveryFormatRequestedUnavailable fault indicating that the requested delivery format is not supported.

[Body]/wse:Subscribe/wse:Format@Name="http://www.w3.org/2009/02/ws-evt/DeliveryFormats/Unwrap"

Indicate the unwrapped event delivery format.

[Body]/wse:Subscribe/wse:Format@Name="http://www.w3.org/2009/02/ws-evt/DeliveryFormats/Wrap"

Indicate the wrapped event delivery format.

[Body]/wse:Subscribe/wse:Expires

Requested expiration time for the subscription. (No implied value.) The event source defines the actual expiration and is not constrained to use a time less or greater than the requested expiration. The expiration time may be a specific time or a duration from the subscription's creation time. Both specific times and durations are interpreted based on the event source's clock.

If this element does not appear, then the request is for a subscription that will not expire. That is, the subscriber is requesting the event source to create a subscription with an indefinite lifetime. If the event source grants such a subscription, it may be terminated by the subscriber using an Unsubscribe request, or it may be terminated by the event source at any time for reasons such as connection termination, resource constraints, or system shut-down.

If the expiration time is either a zero duration or a specific time that occurs in the past according to the event source, then the request MUST fail, and the event source MUST generate a wse:InvalidExpirationTime fault indicating that an invalid expiration time was requested.

Some event sources may not have a "wall time" clock available, and so are only able to accept durations as expirations. If such a source receives a Subscribe request containing a specific time expiration, then the request MAY fail; if so, the event source MUST generate a wse:UnsupportedExpirationType fault indicating that an unsupported expiration type was requested.

[Body]/wse:Subscribe/wse:Filter

A Boolean expression in some dialect, either as a string or as an XML fragment (see [[Body]/wse:Subscribe/wse:Filter/@Dialect ]). If the expression evaluates to false for a notification, the notification MUST NOT be sent to the event sink. Implied value is an expression that always returns true. If the event source does not support filtering, then a request that specifies a filter MUST fail, and the event source MUST generate a wse:FilteringNotSupported fault indicating that filtering is not supported.

If the event source supports filtering but cannot honor the requested filtering, the request MUST fail, and the event source MUST generate a wse:FilteringRequestedUnavailable fault indicating that the requested filter dialect is not supported.

It is possible for a Subscribe request to contain a filter that will never evaluate to true for the lifetime of the Subscription. If an Event Source detects this condition it MUST generate a wse:EmptyFilter fault in response to the Subscribe request message.

[Body]/wse:Subscribe/wse:Filter/@Dialect

Implied value is "http://www.w3.org/TR/1999/REC-xpath-19991116".

While an XPath predicate expression provides great flexibility and power, alternate filter dialects may be defined. For instance, a simpler, less powerful dialect might be defined for resource-constrained implementations, or a new dialect might be defined to support filtering based on data not included in the notification message itself. If desired, a filter dialect could allow the definition of a composite filter that contained multiple filters from other dialects.

[Body]/wse:Subscribe/wse:Filter/@Dialect=" http://www.w3.org/TR/1999/REC-xpath-19991116 "

Value of [Body]/wse:Subscribe/wse:Filter is an XPath [XPath 1.0] predicate expression (PredicateExpr); the context of the expression is:

Context Node: the root of the event XML.
Context Position: 1.
Context Size: 1.
Variable Bindings: None.
Function Libraries: Core Function Library [XPath 1.0].
Namespace Declarations: The [in-scope namespaces] property [XML Infoset] of /s:Envelope/s:Body/*/wse:Filter.

Other message information headers defined by WS-Addressing [WS-Addressing] MAY be included in the request and response messages, according to the usage and semantics defined in WS-Addressing.

Other components of the outline above are not further constrained by this specification.

If included within the Subscribe request message, the wse:NotifyTo and wse:EndTo SHOULD have some cursory validity checking performed before the Subscribe response is returned. While not all errors can be detected prior to sending a message to those EPRs, some obvious ones can be detected. For example, an unsupported transport specified within the wsa:Address IRI. Detecting these errors during Subscribe processing will lessen the chances of the subscriber creating an unusable subscription. If this check is performed and a problem is detected then the event source MUST generate a wse:UnusableEPR fault rather than returning the SubscribeResponse message.

If the event source accepts a request to create a subscription, it MUST reply with a response of the following form:

[Action]
  http://www.w3.org/2009/02/ws-evt/SubscribeResponse

[Body]
  <wse:SubscribeResponse ...>
    <wse:SubscriptionManager>
      wsa:EndpointReferenceType
    </wse:SubscriptionManager>
    <wse:Expires>(xs:dateTime | xs:duration)</wse:Expires>
    xs:any*
  </wse:SubscribeResponse>

The following describes additional, normative constraints on the outline listed above:

[Body]/wse:SubscribeResponse/wse:SubscriptionManager

The EPR of the subscription manager for this subscription.

In some cases, it is convenient for all EPRs issued by a single event source to address a single Web service and use a reference parameter to distinguish among the active subscriptions.

[Body]/wse:SubscribeResponse/wse:Expires

The expiration time assigned by the event source. The expiration time MAY be either an absolute time or a duration but SHOULD be of the same type as the requested expiration (if any).

If this element does not appear, then the subscription will not expire. That is, the subscription has an indefinite lifetime. It may be terminated by the subscriber using an Unsubscribe request, or it may be terminated by the event source at any time for reasons such as connection termination, resource constraints, or system shut-down.

Other components of the outline above are not further constrained by this specification.

If the event source chooses not to accept a subscription, the request MUST fail, and the event source MUST generate a wse:EventSourceUnableToProcess fault indicating that the request was not accepted.

Example 4-1 lists another hypothetical request to create a subscription.

Example 4-1: Second hypothetical request to create a subscription

(01) <s12:Envelope 
(02)     xmlns:s12="http://www.w3.org/2003/05/soap-envelope"
(03)     xmlns:wsa="http://www.w3.org/2005/08/addressing"
(04)     xmlns:wse="http://www.w3.org/2009/02/ws-evt"
(05)     xmlns:ew="http://www.example.com/warnings" >
(06)   <s12:Header>
(07)     <wsa:Action>
(08)       http://www.w3.org/2009/02/ws-evt/Subscribe
(09)     </wsa:Action>
(10)     <wsa:MessageID>
(11)       uuid:e1886c5c-5e86-48d1-8c77-fc1c28d47180
(12)     </wsa:MessageID>
(13)     <wsa:ReplyTo>
(14)      <wsa:Address>http://www.example.com/MyEvEntsink</wsa:Address>
(15)      <wsa:ReferenceParameters>
(16)        <ew:MySubscription>2597</ew:MySubscription>
(17)      </wsa:ReferenceParameters>
(18)     </wsa:ReplyTo>
(19)     <wsa:To>http://www.example.org/oceanwatch/EventSource</wsa:To>
(20)   </s12:Header>
(21)   <s12:Body>
(22)     <wse:Subscribe>
(23)       <wse:EndTo>
(24)         <wsa:Address>
(25)           http://www.example.com/MyEventSink
(26)         </wsa:Address>
(27)         <wsa:ReferenceParameters>
(28)           <ew:MySubscription>2597</ew:MySubscription>
(29)         </wsa:ReferenceParameters>
(30)       </wse:EndTo>
(31)       <wse:Delivery>
(32)         <wse:NotifyTo>
(33)           <wsa:Address>
(34)             http://www.other.example.com/OnStormWarning
(35)           </wsa:Address>
(36)           <wsa:ReferenceParameters>
(37)             <ew:MySubscription>2597</ew:MySubscription>
(38)           </wsa:ReferenceParameters>
(39)         </wse:NotifyTo>
(40)       </wse:Delivery>
(41)       <wse:Expires>2004-06-26T21:07:00.000-08:00</wse:Expires>
(42)       <wse:Filter xmlns:ow="http://www.example.org/oceanwatch" >
(43)         /*/ow:Speed/[node() &gt; 50]
(44)       </wse:Filter>
(45)     </wse:Subscribe>
(46)   </s12:Body>
(47) </s12:Envelope>

Like the request in Example 2-1, lines (07-09) of Example 4-1 indicate the message is a request to create a subscription. Line (19) indicates that it is sent to a hypothetical event source of ocean events.

Lines (13-18) indicate where to send the response to this request, lines (23-30) indicate where to send a SubscriptionEnd message if necessary, and lines (31-34) indicate how and where to send notifications.

Line (41) indicates the event sink would prefer to have the subscription expire on 26 June 2004 at 9:07 PM Pacific time.

Lines (42-44) indicate the event sink only wants weather reports where the speed of wind is greater than 50.

Example 4-2 lists a hypothetical response to the request in Example 4-1.

Example 4-2: Hypothetical response to second subscribe request

(01) <s12:Envelope 
(02)     xmlns:s12="http://www.w3.org/2003/05/soap-envelope"
(03)     xmlns:wsa="http://www.w3.org/2005/08/addressing"
(04)     xmlns:wse="http://www.w3.org/2009/02/ws-evt"
(05)     xmlns:ew="http://www.example.com/warnings"
(06)     xmlns:ow="http://www.example.org/oceanwatch" >
(07)   <s12:Header>
(08)     <wsa:Action>
(09)       http://www.w3.org/2009/02/ws-evt/SubscribeResponse
(10)     </wsa:Action>
(11)     <wsa:RelatesTo>
(12)       uuid:e1886c5c-5e86-48d1-8c77-fc1c28d47180
(13)     </wsa:RelatesTo>
(14)     <wsa:To>http://www.example.com/MyEventSink</wsa:To>
(15)     <ew:MySubscription wsa:IsReferenceParameter="true">
(16)       2597
(17)     </ew:MySubscription>
(18)   </s12:Header>
(19)   <s12:Body>
(20)     <wse:SubscribeResponse>
(21)       <wse:SubscriptionManager>
(22)         <wsa:Address>
(23)           http://www.example.org/oceanwatch/SubscriptionManager
(24)         </wsa:Address>
(25)         <wsa:ReferenceParameters>
(26)           <x:SubID xmlns:x="http://example.com">
(27)             uuid:22e8a584-0d18-4228-b2a8-3716fa2097fa
(28)           </x:SubID>
(29)         </wsa:ReferenceParameters>
(30)       </wse:SubscriptionManager>
(31)       <wse:Expires>2004-07-01T00:00:00.000-00:00</wse:Expires>
(32)     </wse:SubscribeResponse>
(33)   </s12:Body>
(34) </s12:Envelope>

Like the response in Example 2-2, lines (08-10) of Example 4-2 indicate this message is a response to a request to create a subscription, and lines (11-13) indicate that it is a response to the request in Example 4-1 . Lines (14-17) indicate the response is sent to the event sink indicated in lines (13-18) of Example 4-1. Lines (21-30) provide the address of the subscription manager for this subscription; note that this particular response uses the x:SubID element as a reference parameter to distinguish this subscription EPR from other subscription EPRs. Finally, line (31) indicates the subscription will expire on 1 July 2004 unless renewed; there is no requirement that this time be necessarily longer or shorter than the requested expiration (line (41) of Example 4-1).

4.2 Renew

To update the expiration for a subscription, subscription managers MUST support requests to renew subscriptions.

To renew a subscription, the subscriber sends a request of the following form to the subscription manager:

[Action]
  http://www.w3.org/2009/02/ws-evt/Renew

[Body]
  <wse:Renew ...>
    <wse:Expires>(xs:dateTime | xs:duration)</wse:Expires> ?
    xs:any*
  </wse:Renew>

Components of the outline listed above are additionally constrained as for a request to create a subscription (see 4.1 Subscribe). Other components of the outline above are not further constrained by this specification.

If the subscription manager accepts a request to renew a subscription, it MUST reply with a response of the following form:

[Action]
  http://www.w3.org/2009/02/ws-evt/RenewResponse

[Body]
  <wse:RenewResponse ...>
    <wse:Expires>(xs:dateTime | xs:duration)</wse:Expires> ?
    xs:any*
  </wse:RenewResponse>

Components of the outline listed above are constrained as for a response to a subscribe request (see 4.1 Subscribe) with the following addition(s):

[Body]/wse:RenewResponse/wse:Expires: If the requested expiration is a duration, then the implied start of that duration is the time when the subscription manager starts processing the Renew request.

If the subscription manager chooses not to renew this subscription, the request MUST fail, and the subscription manager MUST generate a wse:UnableToRenew fault indicating that the renewal was not accepted.

Other components of the outline above are not further constrained by this specification.

Example 4-3 lists a hypothetical request to renew the subscription created in Example 4-2.

Example 4-3: Hypothetical request to renew second subscription

(01) <s12:Envelope 
(02)     xmlns:s12="http://www.w3.org/2003/05/soap-envelope"
(03)     xmlns:wsa="http://www.w3.org/2005/08/addressing"
(04)     xmlns:wse="http://www.w3.org/2009/02/ws-evt"
(05)     xmlns:ow="http://www.example.org/oceanwatch" >
(06)   <s12:Header>
(07)     <wsa:Action>
(08)       http://www.w3.org/2009/02/ws-evt/Renew
(09)     </wsa:Action>
(10)     <wsa:MessageID>
(11)       uuid:bd88b3df-5db4-4392-9621-aee9160721f6
(12)     </wsa:MessageID>
(13)     <wsa:ReplyTo>
(14)      <wsa:Address>http://www.example.com/MyEventSink</wsa:Address>
(15)     </wsa:ReplyTo>
(16)     <wsa:To>
(17)       http://www.example.org/oceanwatch/SubscriptionManager
(18)     </wsa:To>
(19)     <x:SubID wsa:IsReferenceParameter="true" xmlns:x="http://example.com">
(20)       uuid:22e8a584-0d18-4228-b2a8-3716fa2097fa
(21)     </x:SubID>
(22)   </s12:Header>
(23)   <s12:Body>
(24)     <wse:Renew>
(25)       <wse:Expires>2004-06-26T21:07:00.000-08:00</wse:Expires>
(26)     </wse:Renew>
(27)   </s12:Body>
(28) </s12:Envelope>

Lines (07-09) indicate this is a request to renew a subscription. Lines (19-21) contain the reference parameter that indicates the subscription to be renewed is the one created in Example 4-2. Line (25) in Example 4-3 indicates the request is to extend the subscription until 26 June 2004 at 9:07 PM Pacific.

Example 4-4 lists a hypothetical response to the request in Example 4-3.

Example 4-4: Hypothetical response to renew request

(01) <s12:Envelope
(02)     xmlns:s12="http://www.w3.org/2003/05/soap-envelope"
(03)     xmlns:wsa="http://www.w3.org/2005/08/addressing"
(04)     xmlns:wse="http://www.w3.org/2009/02/ws-evt"
(05)     xmlns:ow="http://www.example.org/oceanwatch" >
(06)   <s12:Header>
(07)     <wsa:Action>
(08)      http://www.w3.org/2009/02/ws-evt/RenewResponse
(09)     </wsa:Action>
(10)     <wsa:RelatesTo>
(11)       uuid:bd88b3df-5db4-4392-9621-aee9160721f6
(12)     </wsa:RelatesTo>
(13)     <wsa:To>http://www.example.com/MyEventSink</wsa:To>
(14)   </s12:Header>
(15)   <s12:Body>
(16)     <wse:RenewResponse>
(17)       <wse:Expires>2004-06-26T12:00:00.000-00:00</wse:Expires>
(18)     </wse:RenewResponse>
(19)   </s12:Body>
(20) </s12:Envelope>

Line (17) in Example 4-4 indicates the subscription has been extended only until 26 June 2004 at noon.

4.3 GetStatus

To get the status of a subscription, the subscriber sends a request of the following form to the subscription manager:

[Action]
  http://www.w3.org/2009/02/ws-evt/GetStatus

[Body]
  <wse:GetStatus ...>
    xs:any*
  </wse:GetStatus>

Components of the outline listed above are additionally constrained as for a request to renew a subscription (see 4.2 Renew). Other components of the outline above are not further constrained by this specification.

If the subscription is valid and has not expired, the subscription manager MUST reply with a response of the following form:

[Action]
  http://www.w3.org/2009/02/ws-evt/GetStatusResponse

[Body]
  <wse:GetStatusResponse ...>
    <wse:Expires>(xs:dateTime | xs:duration)</wse:Expires> ?
    xs:any*
  </wse:GetStatusResponse>

Components of the outline listed above are constrained as for a response to a renew request (see 4.2 Renew). Other components of the outline above are not further constrained by this specification.

Example 4-5 lists a hypothetical request to get the status of the subscription created in Example 4-2.

Example 4-5: Hypothetical request to get the status of the second subscription

(01) <s12:Envelope
(02)     xmlns:s12="http://www.w3.org/2003/05/soap-envelope"
(03)     xmlns:wsa="http://www.w3.org/2005/08/addressing"
(04)     xmlns:wse="http://www.w3.org/2009/02/ws-evt"
(05)     xmlns:ow="http://www.example.org/oceanwatch" >
(06)   <s12:Header>
(07)     <wsa:Action>
(08)       http://www.w3.org/2009/02/ws-evt/GetStatus
(09)     </wsa:Action>
(10)     <wsa:MessageID>
(11)       uuid:bd88b3df-5db4-4392-9621-aee9160721f6
(12)     </wsa:MessageID>
(13)     <wsa:ReplyTo>
(14)       <wsa:Address>http://www.example.com/MyEventSink</wsa:Address>
(15)     </wsa:ReplyTo>
(16)     <wsa:To>
(17)       http://www.example.org/oceanwatch/SubscriptionManager
(18)     </wsa:To>
(19)     <x:SubID wsa:IsReferenceParameter="true" xmlns:x="http://example.com">
(20)       uuid:22e8a584-0d18-4228-b2a8-3716fa2097fa
(21)     </x:SubID>
(22)   </s12:Header>
(23)   <s12:Body>
(24)     <wse:GetStatus />
(25)   </s12:Body>
(26) </s12:Envelope>

Lines (07-09) indicate this is a request to get the status of a subscription. Lines (16-21) indicate that the request is sent to the subscription manager for the subscription created in Example 4-2.

Example 4-6 lists a hypothetical response to the request in Example 4-5.

Example 4-6: Hypothetical response to get status request

(01) <s12:Envelope 
(02)     xmlns:s12="http://www.w3.org/2003/05/soap-envelope"
(03)     xmlns:wsa="http://www.w3.org/2005/08/addressing"
(04)     xmlns:wse="http://www.w3.org/2009/02/ws-evt"
(05)     xmlns:ow="http://www.example.org/oceanwatch" >
(06)   <s12:Header>
(07)     <wsa:Action>
(08)       http://www.w3.org/2009/02/ws-evt/GetStatusResponse
(09)     </wsa:Action>
(10)     <wsa:RelatesTo>
(11)       uuid:bd88b3df-5db4-4392-9621-aee9160721f6
(12)     </wsa:RelatesTo>
(13)     <wsa:To>http://www.example.com/MyEventSink</wsa:To>
(14)   </s12:Header>
(15)   <s12:Body>
(16)     <wse:GetStatusResponse>
(17)       <wse:Expires>2004-06-26T12:00:00.000-00:00</wse:Expires>
(18)     </wse:GetStatusResponse>
(19)   </s12:Body>
(20) </s12:Envelope>

Line (17) in Example 4-6 indicates the subscription will expire on 26 June 2004 at noon.

4.4 Unsubscribe

Though subscriptions expire eventually, to minimize resources, the subscribing event sink SHOULD explicitly delete a subscription when it no longer wants notifications associated with the subscription.

To explicitly delete a subscription, a subscribing event sink sends a request of the following form to the subscription manager:

[Action]
  http://www.w3.org/2009/02/ws-evt/Unsubscribe

[Body]
  <wse:Unsubscribe ...>
    xs:any*
  </wse:Unsubscribe>

Components of the outline above are additionally constrained only as for a request to renew a subscription (see 4.2 Renew). For example, the faults listed there are also defined for a request to delete a subscription.

If the subscription manager accepts a request to delete a subscription, it MUST reply with a response of the following form:

[Action]
  http://www.w3.org/2009/02/ws-evt/UnsubscribeResponse

[Body]
  <wse:UnsubscribeResponse ...>
    xs:any*
  </wse:UnsubscribeResponse>

Components of the outline listed above are not further constrained by this specification.

Example 4-7 lists a hypothetical request to delete the subscription created in Example 4-2.

Example 4-7: Hypothetical unsubscribe request to delete second subscription

(01) <s12:Envelope 
(02)     xmlns:s12="http://www.w3.org/2003/05/soap-envelope"
(03)     xmlns:wsa="http://www.w3.org/2005/08/addressing"
(04)     xmlns:wse="http://www.w3.org/2009/02/ws-evt"
(05)     xmlns:ow="http://www.example.org/oceanwatch" >
(06)   <s12:Header>
(07)     <wsa:Action>
(08)       http://www.w3.org/2009/02/ws-evt/Unsubscribe
(09)     </wsa:Action>
(10)     <wsa:MessageID>
(11)       uuid:2653f89f-25bc-4c2a-a7c4-620504f6b216
(12)     </wsa:MessageID>
(13)     <wsa:ReplyTo>
(14)      <wsa:Address>http://www.example.com/MyEventSink</wsa:Address>
(15)     </wsa:ReplyTo>
(16)     <wsa:To>
(17)       http://www.example.org/oceanwatch/SubscriptionManager
(18)     </wsa:To>
(19)     <x:SubID wsa:IsReferenceParameter="true" xmlns:x="http://example.com">
(20)       uuid:22e8a584-0d18-4228-b2a8-3716fa2097fa
(21)     </x:SubID>
(22)   </s12:Header>
(23)   <s12:Body>
(24)     <wse:Unsubscribe />
(25)   </s12:Body>
(26) </s12:Envelope>

Lines (07-09) in Example 4-7 indicate the message is a request to delete a subscription. Lines (16-21) indicate that the request is addressed to the manager for the subscription created in Example 4-2.

Example 4-8 lists a hypothetical response to the request in Example 4-7.

Example 4-8: Hypothetical response to unsubscribe request

(01) <s12:Envelope 
(02)     xmlns:s12="http://www.w3.org/2003/05/soap-envelope"
(03)     xmlns:wsa="http://www.w3.org/2005/08/addressing" >
(04)   <s12:Header>
(05)     <wsa:Action>
(06)       http://www.w3.org/2009/02/ws-evt/UnsubscribeResponse
(07)     </wsa:Action>
(08)     <wsa:RelatesTo>
(09)       uuid:2653f89f-25bc-4c2a-a7c4-620504f6b216
(10)     </wsa:RelatesTo>
(11)     <wsa:To>http://www.example.com/MyEventSink</wsa:To>
(12)   </s12:Header>
(13)   <s12:Body>
(14)     <wse:UnsubscribeResponse/>
(15)   </s12:Body>
(16) </s12:Envelope>

4.5 Subscription End

If the event source terminates a subscription unexpectedly, the event source SHOULD send a Subscription End SOAP message to the endpoint reference indicated when the subscription was created (see 4.1 Subscribe). This endpoint reference MUST refer to an endpoint that supports the SubscriptionEndPortType portType. The message MUST be of the following form:

[Action]
  http://www.w3.org/2009/02/ws-evt/SubscriptionEnd

[Body]
  <wse:SubscriptionEnd ...>
    <wse:Status>
      ( http://www.w3.org/2009/02/ws-evt/DeliveryFailure | 
        http://www.w3.org/2009/02/ws-evt/SourceShuttingDown |
        http://www.w3.org/2009/02/ws-evt/SourceCancelling )
    </wse:Status>
    <wse:Reason xml:lang="language identifier" >xs:string</wse:Reason> ?
    xs:any*
  </wse:SubscriptionEnd>

The following describes additional, normative constraints on the outline listed above:

[Body]/wse:SubscriptionEnd/wse:Status = "http://www.w3.org/2009/02/ws-evt/DeliveryFailure": This value MUST be used if the event source terminated the subscription because of problems delivering notifications.
[Body]/wse:SubscriptionEnd/wse:Status = "http://www.w3.org/2009/02/ws-evt/SourceShuttingDown": This value MUST be used if the event source terminated the subscription because the source is being shut down in a controlled manner; that is, if the event source is being shut down but has the opportunity to send a SubscriptionEnd message before it exits.
[Body]/wse:SubscriptionEnd/wse:Status = "http://www.w3.org/2009/02/ws-evt/SourceCancelling": This value MUST be used if the event source terminated the subscription for some other reason before it expired.
[Body]/wse:SubscriptionEnd/wse:Reason: This optional element contains text, in the language specified by the @xml:lang attribute, describing the reason for the unexpected subscription termination.

Other message information headers defined by WS-Addressing [WS-Addressing] MAY be included in the message, according to the usage and semantics defined in WS-Addressing.

Other components of the outline above are not further constrained by this specification.

Example 4-9 lists a hypothetical SubscriptionEnd message corresponding to an early termination of the subscription created in Example 4-1.

Example 4-9: Hypothetical subscription end message

(01) <s12:Envelope 
(02)     xmlns:s12="http://www.w3.org/2003/05/soap-envelope"
(03)     xmlns:wsa="http://www.w3.org/2005/08/addressing"
(04)     xmlns:wse="http://www.w3.org/2009/02/ws-evt" 
(05)     xmlns:ew="http://www.example.com/warnings" >
(06)   <s12:Header>
(07)     <wsa:Action>
(08)       http://www.w3.org/2009/02/ws-evt/SubscriptionEnd
(09)     </wsa:Action>
(10)     <wsa:To>http://www.example.com/MyEventSink</wsa:To>
(11)     <ew:MySubscription wsa:IsReferenceParameter="true">
(12)       2597
(13)     </ew:MySubscription>
(14)   </s12:Header>
(15)   <s12:Body>
(16)     <wse:SubscriptionEnd>
(17)       <wse:Status>wse:SourceShuttingDown</wse:Status>
(18)       <wse:Reason xml:lang="en-US" >
(19)         Event source going off line.
(20)       </wse:Reason>
(21)     </wse:SubscriptionEnd>
(22)   </s12:Body>
(23) </s12:Envelope>

Line (08) is the action URI for Subscription End. Lines (10-13) indicate the message is sent to the EndTo of the subscribe request (lines (23-30) in Example 4-1 .). Line (17) indicates the event source is shutting down, and lines (18-20) indicate that the event source was going off line.

5 Notifications

This specification does not constrain notifications because any message MAY be a notification.

However, if a subscribing event sink wishes to have notifications specifically marked, it MAY specify literal SOAP header blocks in the Subscribe request, in the /s:Envelope/s:Body/wse:Subscribe/wse:NotifyTo/wsa:ReferenceParameters element; per WS-Addressing [WS-Addressing], the event source MUST include each such literal SOAP header block in every notification sent to the endpoint addressed by /s:Envelope/s:Body/wse:Subscribe/wse:NotifyTo.

Example 5-1 lists a hypothetical notification message sent as part of the subscription created by the subscribe request in Example 4-1.

Example 5-1: Hypothetical notification message

(01) <s12:Envelope 
(02)     xmlns:s12="http://www.w3.org/2003/05/soap-envelope"
(03)     xmlns:wsa="http://www.w3.org/2005/08/addressing"
(04)     xmlns:ew="http://www.example.com/warnings"
(05)     xmlns:ow="http://www.example.org/oceanwatch" >
(06)   <s12:Header>
(07)     <wsa:Action>
(08)       http://www.example.org/oceanwatch/2003/WindReport
(09)     </wsa:Action>
(10)     <wsa:MessageID>
(11)       uuid:568b4ff2-5bc1-4512-957c-0fa545fd8d7f
(12)     </wsa:MessageID>
(13)     <wsa:To>http://www.other.example.com/OnStormWarning</wsa:To>
(14)     <ew:MySubscription wsa:IsReferenceParameter="true">
(15)       2597
(16)     </ew:MySubscription>
(18)   </s12:Header>
(19)   <s12:Body>
(20)     <ow:WindReport>
(21)       <ow:Date>030701</ow:Date>
(22)       <ow:Time>0041</ow:Time>
(23)       <ow:Speed>65</ow:Speed>
(24)       <ow:Location>BRADENTON BEACH</ow:Location>
(25)       <ow:County>MANATEE</ow:County>
(26)       <ow:State>FL</ow:State>
(27)       <ow:Lat>2746</ow:Lat>
(28)       <ow:Long>8270</ow:Long>
(29)       <ow:Comments xml:lang="en-US" >
(30)         WINDS 55 WITH GUSTS TO 65. ROOF TORN OFF BOAT HOUSE. REPORTED
(31)         BY STORM SPOTTER. (TBW)
(32)       </ow:Comments>
(33)     </ow:WindReport>
(34)   </s12:Body>
(35) </s12:Envelope>

Lines (13-15) indicate the message is sent to the endpoint indicated by the subscribe request (lines (32-39) in Example 4-1). Line (17) matches the filter in the subscribe request (lines (42-45) in Example 4-1).

6 Faults

All fault messages defined in this specification MUST be sent according to the rules described in WS-Addressing section 4. They are sent to the [fault endpoint], if present and valid. Otherwise they are sent to the [reply endpoint] if present. If neither is present faults may be sent to the [source endpoint].

Endpoints compliant with this specification MUST include required message information headers on all fault messages. Fault messages are correlated as replies using the [relationship] property as defined in WS-Addressing. The [action] property below designates fault messages: http://www.w3.org/2009/02/ws-evt/fault

The definitions of faults use the following properties:

[Code]	The fault code.
[Subcode]	The fault subcode.
[Reason]	The English language reason element.
[Detail]	The detail element. If absent, no detail element is defined for the fault.

The properties above bind to a SOAP 1.2 fault as follows:

<S:Envelope> 
 <S:Header>
   <wsa:Action>
     http://www.w3.org/2009/02/ws-evt/fault
   </wsa:Action>
   <!-- Headers elided for clarity.  -->
 </S:Header>
 <S:Body>
  <S:Fault>
   <S:Code>
     <S:Value> [Code] </S:Value>
     <S:Subcode>
      <S:Value> [Subcode] </S:Value>
     </S:Subcode>
   </S:Code>
   <S:Reason>
     <S:Text xml:lang="en"> [Reason] </S:Text>
   </S:Reason>
   <S:Detail>
      [Detail]
   </S:Detail>    
  </S:Fault>
 </S:Body>
</S:Envelope>

The SOAP 1.1 fault is less expressive and map only [Subcode] and [Reason]. These the properties bind to a SOAP 1.1 fault as follows:

<S11:Envelope> 
 <S11:Body>
  <S11:Fault>
   <faultcode> [Subcode] </faultcode>
   <faultstring xml:lang="en"> [Reason] </faultstring>
  </S11:Fault>
 </S11:Body>
</S11:Envelope>

6.1 Fault Detail RetryAfter Element

The following element is used to convey additional information in the faults.

/wse:RetryAfter: This element (whose content is of type xs:unsignedLong) is a suggested minimum duration in milliseconds to wait before retransmitting the message. Omission of this element indicates that a retry is never likely to succeed.
/wse:RetryAfter/@any: Optional extensibility attributes that do not affect processing.

6.2 InvalidExpirationTime

This fault is sent when a Subscribe request specifies an expiration time that is in the past or an expiration duration of zero.

[Code]	s12:Sender
[Subcode]	wse:InvalidExpirationTime
[Reason]	The expiration time requested is invalid.
[Detail]	none

6.3 UnsupportedExpirationType

This fault is sent when a Subscribe request specifies an expiration time and the event source is only capable of accepting expiration durations; for instance, if the event source does not have access to absolute time.

[Code]	s12:Sender
[Subcode]	wse:UnsupportedExpirationType
[Reason]	Only expiration durations are supported.
[Detail]	none

6.4 FilteringNotSupported

This fault is sent when a Subscribe request contains a filter and the event source does not support filtering.

[Code]	s12:Sender
[Subcode]	wse:FilteringNotSupported
[Reason]	Filtering is not supported.
[Detail]	none

6.5 FilteringRequestedUnavailable

This fault is sent when a Subscribe request specifies a filter dialect that the event source does not support. Optionally, this fault may contain a list of supported filter dialect URIs in the Detail property.

[Code]	s12:Sender
[Subcode]	wse:FilteringRequestedUnavailable
[Reason]	The requested filter dialect is not supported.
[Detail]	<wse:SupportedDialect> + Optional; one per filter dialect supported by the receiver

6.6 EventSourceUnableToProcess

This fault is sent when the event source is not capable of fulfilling a Subscribe request for local reasons unrelated to the specific request.

[Code]	s12:Receiver
[Subcode]	wse:EventSourceUnableToProcess
[Reason]	Text explaining the failure; e.g., "The event source has too many subscribers".
[Detail]	<wse:RetryAfter> ? (Optional)

6.7 UnableToRenew

This fault is sent when the event source is not capable of fulfilling a Renew request for local reasons unrelated to the specific request.

[Code]	s12:Receiver
[Subcode]	wse:UnableToRenew
[Reason]	Text explaining the failure; e.g., "The event source has too many subscribers".
[Detail]	<wse:RetryAfter> ? (Optional)

6.8 InvalidMessage

If a request message does not comply with the corresponding outline listed above, the request MUST fail and the event source or subscription manager MUST generate the following fault indicating that the request is invalid:

[Code]	s12:Sender
[Subcode]	wse:InvalidMessage
[Reason]	The message is not valid and cannot be processed.
[Detail]	The invalid message

6.9 DeliveryFormatRequestUnavailable

This fault is sent when a Subscribe request specifies a delivery format that is not supported by the event source. Optionally, this fault may contain a list of supported delivery format URIs in the Detail property.

[Code]	s12:Sender
[Subcode]	wse:DeliveryFormatRequestedUnavailable
[Reason]	The requested delivery format is not supported.
[Detail]	<wse:SupportedDeliveryFormat> + Optional, one per delivery format supported by the receiver.

6.10 EmptyFilter

This fault MAY be generated when an Event Source detects a wse:Subscribe request containing a filter that, for whatever reason, will never evaluate to true.

[Code]	s12:Sender
[Subcode]	wse:EmptyFilter
[Reason]	The wse:Filter would result in zero Notifications.
[Detail]	The wse:Filter value.

6.11 UnusableEPR

This fault MAY be generated when an Event Source detects that the wse:NotifyTo or wse:EndTo EPR is unusable.

[Code]	s12:Sender
[Subcode]	wse:UnusableEPR
[Reason]	An EPR in the Subscribe request message is unusable.
[Detail]	The specific EPR that generated the error and why.

7 Security Considerations

7.1 Message Security

It is strongly RECOMMENDED that the communication between services be secured using the mechanisms described in WS-Security [WS-Security]. In order to properly secure messages, the body and all relevant headers need to be included in the signature. Specifically, any headers identified in the <wse:NotifyTo> element and standard messaging headers, such as those from WS-Addressing [WS-Addressing], need to be signed with the body in order to "bind" the two together. For messages with empty bodies, the <s12:Body> element should be signed so content cannot be added in transit.

Different security mechanisms may be desired depending on the frequency of messages. For example, for infrequent messages, public key technologies may be adequate for integrity and confidentiality. However, for high-frequency events, it may be more performant to establish a security context for the events using the mechanisms described in WS-Trust [WS-Trust] and WS-SecureConversation [WS-SecureConversation].

It should be noted that if a shared secret is used it is RECOMMENDED that derived keys be used to strengthen the secret as described in WS-SecureConversation.

The following list summarizes common classes of attacks that apply to this protocol and identifies the mechanism to prevent/mitigate the attacks:

Message alteration - Alteration is prevented by including signatures of the message information using WS-Security.
Message disclosure - Confidentiality is preserved by encrypting sensitive data using WS-Security.
Key integrity - Key integrity is maintained by using the strongest algorithms possible (by comparing secured policies - see WS-Policy [WS-Policy] and WS-SecurityPolicy [WS-SecurityPolicy]).
Authentication - Authentication is established using the mechanisms described in WS-Security and WS-Trust. Each message is authenticated using the mechanisms described in WS-Security.
Accountability - Accountability is a function of the type of and string of the key and algorithms being used. In many cases, a strong symmetric key provides sufficient accountability. However, in some environments, strong PKI signatures are required.
Availability - All reliable messaging services are subject to a variety of availability attacks. Replay detection is a common attack and it is RECOMMENDED that this be addressed by the mechanisms described in WS-Security. Other attacks, such as network-level denial of service attacks are harder to avoid and are outside the scope of this specification. That said, care should be taken to ensure that minimal state is saved prior to any authenticating sequences.
Replay - Messages may be replayed for a variety of reasons. To detect and eliminate this attack, mechanisms should be used to identify replayed messages such as the timestamp/nonce outlined in WS-Security. Alternatively, and optionally, other technologies, such as sequencing, can also be used to prevent replay of application messages.

7.2 Access Control

It is important for event sources to properly authorize requests. This is especially true for Subscribe requests, as otherwise the ability to subscribe on behalf of a third-party event sink could be used to create a distributed denial-of-service attack.

Some possible schemes for validating Subscribe requests include:

Send a message to the event sink that describes the requested subscription, and then wait for a confirmation message to be returned by the event sink, before the event source accepts the subscription request. While this provides strong assurance that the event sink actually desires the requested subscription, it does not work for event sinks that are not capable of sending a confirmation, and requires additional logic on the event sink.
Require user authentication on the Subscribe request, and allow only authorized users to Subscribe.

Other mechanisms are also possible. Note that event sources that are not reachable from the Internet have less need to control Subscribe requests.

8 Implementation Considerations

Implementations SHOULD generate expirations in subscribe and renew request and response messages that are significantly larger than expected network latency.

Event sinks should be prepared to receive notifications after sending a subscribe request but before receiving a subscribe response message. Event sinks should also be prepared to receive notifications after receiving an unsubscribe response message.

9 Acknowledgements

This specification has been developed as a result of joint work with many individuals and teams, including: Ashok Malhotra (Oracle Corp.), Asir Vedamuthu (Microsoft Corp.), Bob Freund (Hitachi, Ltd.), Doug Davis (IBM), Fred Maciel (Hitachi, Ltd.), Geoff Bullen (Microsoft Corp.), Gilbert Pilz (Oracle Corp.), Greg Carpenter (Microsoft Corp.), Jeff Mischkinsky (Oracle Corp.), Katy Warr (IBM), Li Li (Avaya Communications), Mark Little (Red Hat), Prasad Yendluri (Software AG), Sreedhara Narayanaswamy (CA), Sumeet Vij (Software AG), Vikas Varma (Software AG), Wu Chou (Avaya Communications), Yves Lafon (W3C)

10 References

RFC2119: Key words for use in RFCs to Indicate Requirement Levels , S. Bradner, March 1997. (See http://www.ietf.org/rfc/rfc2119.txt.)
RFC 3986: Uniform Resource Identifier (URI): Generic Syntax , T. Berners-Lee, W3C/MIT, January 2005. (See http://www.ietf.org/rfc/rfc3986.txt.)
SOAP 1.1: Simple Object Access Protocol (SOAP) 1.1 , D. Box, et al, May 2000. (See http://www.w3.org/TR/2000/NOTE-SOAP-20000508/.)
SOAP 1.2: SOAP Version 1.2 Part 1: Messaging Framework , M. Gudgin, et al, June 2003. (See http://www.w3.org/TR/2003/REC-soap12-part1-20030624/.)
WS-Addressing: W3C Recommendation, "Web Services Addressing 1.0 (WS-Addressing)" , May 2006. (See http://www.w3.org/2005/08/addressing/.)
WS-MetadataExchange: Web Services Metadata Exchange (WS-MetadataExchange) , K. Ballinger, et al, September 2004. (See http://www.w3.org/2009/02/ws-mex.)
WS-Policy: W3C Recommendation, "Web Services Policy 1.5 - Framework" , September 2007. (See http://www.w3.org/TR/ws-policy/.)
WS-ReliableMessaging: Web Services Reliable Messaging Protocol (WS-ReliableMessaging) , R. Bilorusets, et al, February 2005. (See http://schemas.xmlsoap.org/ws/2005/02/rm.)
WS-SecureConversation: Web Services Secure Conversation Language (WS-SecureConversation) , S. Anderson, et al, February 2005. (See http://schemas.xmlsoap.org/ws/2005/02/sc.)
WS-Security: Web Services Security: SOAP Message Security 1.0 , A. Nadalin, et al, March 2004. (See http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-soap-message-security-1.0.pdf.)
WS-SecurityPolicy: Web Services Security Policy Language (WS-SecurityPolicy), Version 1.1 , G. Della-Libera, et al, July 2005. (See http://schemas.xmlsoap.org/ws/2005/07/securitypolicy.)
WS-Trust: Web Services Trust Language (WS-Trust) , S. Anderson, et al, February 2005. (See http://schemas.xmlsoap.org/ws/2005/02/trust.)
WSDL 1.1: Web Services Description Language (WSDL) 1.1 , E. Christensen, et al, March 2001. (See http://www.w3.org/TR/2001/NOTE-wsdl-20010315.)
XML Infoset: XML Information Set , J. Cowan, et al, February 2004. (See http://www.w3.org/TR/2004/REC-xml-infoset-20040204/.)
XML Schema, Part 1: XML Schema Part 1: Structures , H. Thompson, et al, October 2004. (See http://www.w3.org/TR/2004/REC-xmlschema-1-20041028/.)
XML Schema, Part 2: XML Schema Part 2: Datatypes , P. Biron, et al, October 2004. (See http://www.w3.org/TR/2004/REC-xmlschema-2-20041028/.)
XPath 1.0: XML Path Language (XPath) Version 1.0 , J. Clark, et al, November 1999. (See http://www.w3.org/TR/1999/REC-xpath-19991116.)

A Advertising Event Information

There are many use cases for WS-Eventing in which it is necessary for the Subscriber and the Event Sink to know the structure and contents of the Notifications that may result from a successful Subscribe request. For example, a developer may wish to use WSDL-based tools to generate service stubs capable of marshalling and dispatching Notifications. In addition to this, the effective use filters (including those in the XPath dialect defined in Section 4.1 as well as other dialects not defined in this specification) requires some knowledge of the schema of the Events over which the filter will be applied.

There are many ways in which an Event Source could describe and advertise the structure of the Events for which it will issue Notifications. To provide a basic level of interoperability, this specification defines the following two optional mechanisms for describing and advertising Event information. If an implementation of a WS-Eventing Event Source chooses to describe the structure of its Events and advertise this description to Subscribers and Event Sinks, it is RECOMMENDED that at least one of these mechanisms be used. Mechanisms other than these MAY be used to describe and advertise the structure of Events, but the definition of such mechanisms is out of the scope of this specification.

A.1 Event Types

A key concept in the description and advertisement of Event information is the "Event Type". An Event Type is a description of the syntactic structure and value space of the set of Events that share that type. Event Types are independent of both the WS-Eventing protocol and the format of the Notifications used to transmit those Events. For example, the following Notification, although transmitted using the Wrapped Notification Format defined in Section 4.1, has the same Event Type as the Notification in Example 5-1:

Example A-1: Hypothetical Wrapped Notification

 (01) <s12:Envelope xmlns:s12="http://www.w3.org/2003/05/soap-envelope"
 (02)               xmlns:wsa="http://www.w3.org/2005/08/addressing"
 (03)               xmlns:wse="http://www.w3.org/2009/02/ws-evt"
 (04)               xmlns:ow="http://www.example.org/oceanwatch">
 (05)   <s12:Header>
 (06)     <wsa:Action>
 (07)       http://www.w3.org/2009/02/ws-evt/wrap/GenericSinkPortType/NotifyEvent
 (08)     </wsa:Action>
 (09)     . . .
 (10)   </s12:Header>
 (11)   <s12:Body>
 (12)     <wse:Notify actionURI="http://www.example.org/oceanwatch/2003/WindReport">
 (13)       <ow:WindReport>
 (14)         <ow:Date>030701</ow:Date>
 (15)         <ow:Time>0041</ow:Time>
 (16)         <ow:Speed>65</ow:Speed>
 (17)         <ow:Location>BRADENTON BEACH</ow:Location>
 (18)         <ow:County>MANATEE</ow:County>
 (19)         <ow:State>FL</ow:State>
 (20)         <ow:Lat>2746</ow:Lat>
 (21)         <ow:Long>8270</ow:Long>
 (22)         <ow:Comments xml:lang="en-US" >
 (23)           WINDS 55 WITH GUSTS TO 65. ROOF TORN OFF BOAT HOUSE. REPORTED
 (24)           BY STORM SPOTTER. (TBW)
 (25)         </ow:Comments>
 (26)       </ow:WindReport>
 (27)     </wse:Notify>
 (28)   </s12:Body>
 (29) </s12:Envelope>

A.2 Event Descriptions

Event Types MAY be described within an EventDescriptions element where they are defined by Global Element Declarations in XML Schema [XML Schema, Part 1], [XML Schema, Part 2]. The EventDescriptions element has the following form:

<wse:EventDescriptions targetNamespace="xs:anyURI" ...>
  <wse:types>
    [ <xs:import namespace="xs:anyURI" schemaLocation="xs:anyURI"/> ? |
      <xs:schema targetNamespace="xs:anyURI"/> ? |
      other extension elements ] *
  </wse:types>
  <wse:eventType name="xs:NCName" element="xs:QName" actionURI="xs:anyURI" ...>
    xs:any *
  </wse:eventType> +
  xs:any *
</wse:EventDescriptions>

The XML Schema for the EventDesciptions element can be found in Apppendix E. The following describes additional, normative constraints on the outlined listed above:

/wse:EventDescriptions: This element contains the declarations of all the Event Types that apply to a given context, such as a particular Event Source.
/wse:EventDescriptions/@targetNamespace: This attribute defines the namespace affiliation of the Event Types declared within the EventDescriptions element. Its value MUST be an absolute IRI [IETF RFC 3987]. It MAY be dereferencable.
/wse:EventDescriptions/wse:types: As described earlier, an Event Type is defined by a Global Element Declaration (GED) in XML Schema. This element contains collections of imported and inlined schema components that describe the GEDs that are used to define Event Types.
/wse:EventDescriptions/wse:eventType: This element describes a specific Event Type.
/wse:EventDescriptions/wse:eventType/@name: This attribute provides a unique name for this Event Type amongst all the Event Types defined by the enclosing wse:EventDescriptions element. In conjunction with a Prefix that is associated with the value of /wse:EventDescriptions/@targetNamespace namespace URI, the value of this attribute MAY be used as the LocalPart of a QName that identifies this Event Type outside the context of the enclosing wse:EventDescriptions element.
/wse:EventDescriptions/wse:eventType/@element: This attribute refers to a GED defined or imported in the /wse:EventDescriptions/wse:types element. The referenced GED serves as the definition of this Event Type.
/wse:EventDescriptions/wse:eventType/@actionURI: This attribute provides a value for the various 'action' properties and attributes which, depending upon the format of the Notification used to transmit the Event, serve as a potential aide to identifying the semantics implied by the message.

The following is an example of a EventDescriptions element that could serve as a description of the Event Type used in Example 5-1 and Example A-1.

Example A-2: EventDescriptions

(01) <wse:EventDescriptions targetNamepace="http://www.example.org/oceanwatch/notifications"
(02)                        xmlns:wse="http://www.w3.org/2009/02/ws-evt"
(03)                        xmlns:ow="http://www.example.org/oceanwatch">
(04)   <wse:types>
(05)     <xs:schema targetNamepace="http://www.example.org/oceanwatch">
(06)       <xs:include schemaLocation="http://www.example.org/schemas/oceanwatch.xsd"/>
(07)       <xs:element name="WindReport" type="ow:WindReportType"/>
(08)     </xs:schema>
(09)   </wse:types>
(10)
(11)   <wse:eventType name="WindReportEvent"
(12)                  element="ow:WindReport"
(13)                  actionURI="http://www.example.org/oceanwatch/2003/WindReport"/>
(14) </wsem:EventDescriptions>

Lines (11-13) describe an Event Type with a QName of "{http://www.example.org/oceanwatch/notifications}:WindReportEvent". The GED for this Event Type is defined on line (07) as being of type "{http://www.example.org/oceanwatch}:WindReportType".

A.2.1 Retrieving Event Descriptions

Although there are many ways in which an Event Source can make its EventDescriptions available to potential Subscribers and Event Sinks, this specification RECOMMENDS the use of the mechanisms described in WS-MetadataExchange [WS-MetadataExchange]. This specification defines the following URI to serve as the Dialect URI for the wse:EventDescriptions element.

http://www.w3.org/2009/02/ws-evt/EventDescriptions

When a mex:GetMetadata request is targeted to a Subscription Endpoint with a mex:Dialect@URI of either "http://www.w3.org/2009/02/ws-evt/EventDescriptions" or "http://www.w3.org/2009/06/ws-mex/Dialects/ws-mex-all", the mex:Metadata element of the mex:GetMetadataResponse MAY include (in addition to other Metadata Sections that may be present) a single Metadata Section with a wse:EventDescriptions as the dialect specific element. The value of the @Dialect attribute for this Metadata Section MUST be "http://www.w3.org/2009/02/ws-evt/EventDescriptions". The value of the @Identifier attribute for this Metadata Section MUST be equal to the value of its wse:EventDescriptions/@targetNamespace.

The following GetMetadata request, when sent to the Subscription Endpoint used in Example 2-1

Example A-3: GetMetadata Request for EventDescriptions

(01) <s12:Envelope xmlns:s12="http://www.w3.org/2003/05/soap-envelope"
(02)                  xmlns:wsa="http://www.w3.org/2005/08/addressing"
(03)                  xmlns:wse="http://www.w3.org/2009/02/ws-evt"
(04)                  xmlns:mex="http://www.w3.org/2009/02/ws-mex">
(05)   <s12:Header>
(06)     <wsa:Action>
(07)       http://www.w3.org/2009/02/ws-mex/GetMetadata
(08)     </wsa:Action>
(09)     <wsa:MessageID>
(10)       uuid:126287f0-521d-11de-8a39-0800200c9a66
(11)     </wsa:MessageID>
(12)     <wsa:To>http://www.example.org/oceanwatch/EventSource</wsa:To>
(13)   </s12:Header>
(14)   <s12:Body>
(15)     <mex:GetMetadata>
(16)       <mex:Dialect URI="http://www.w3.org/2009/02/ws-evt/EventDescriptions"/>
(17)     </mex:GetMetadata>
(18)   </s12:Body>
(19) </s12:Envelope>

returns the following GetMetadataResponse element

Example A-4: GetMetadataResponse with EventDescriptions

(01) <s12:Envelope xmlns:s12="http://www.w3.org/2003/05/soap-envelope"
(02)                  xmlns:wsa="http://www.w3.org/2005/08/addressing"
(03)                  xmlns:wse="http://www.w3.org/2009/02/ws-evt"
(04)                  xmlns:mex="http://www.w3.org/2009/02/ws-mex">
(05)   <s12:Header>
(06)     <wsa:Action>
(07)       http://www.w3.org/2009/02/ws-mex/GetMetadataResponse
(08)     </wsa:Action>
(09)     <wsa:RelatesTo>
(10)       uuid:126287f0-521d-11de-8a39-0800200c9a66
(11)     </wsa:RelatesTo>
(12)   </s12:Header>
(13)   <s12:Body>
(14)     <mex:Metadata>
(15)       <mex:MetadataSection Dialect="http://www.w3.org/2009/02/ws-evt/EventDescriptions"
(16)                            Identifier="http://www.example.org/oceanwatch/notifications">
(17)         <wse:EventDescriptions targetNamepace="http://www.example.org/oceanwatch/notifications"
(18)                                xmlns:wse="http://www.w3.org/2009/02/ws-evt"
(19)                                xmlns:ow="http://www.example.org/oceanwatch">
(20)           <wse:types>
(21)             <xs:schema targetNamepace="http://www.example.org/oceanwatch">
(22)               <xs:include schemaLocation="http://www.example.org/schemas/oceanwatch.xsd"/>
(23)               <xs:element name="WindReport" type="ow:WindReportType">
(24)             </xs:schema>
(25)           </wse:types>
(26)
(27)           <wse:eventType name="WindReportNotification"
(28)                          element="ow:WindReport"
(29)                          actionURI="http://www.example.org/oceanwatch/2003/WindReport"/>
(30)         </wsem:EventDescriptions>
(31)       </mex:MetadataSection
(32)     </mex:Metadata>
(33)   </s12:Body>
(34) </s12:Envelope>

A.2.2 Bindings for Event Descriptions

For any Notification Format it should be possible to determine how a given wse:eventType will appear on the wire as a Notification in a Subscription created with that format. The following sections define how wse:eventType's bind to Notifications for the two Notification Formats defined in this specification; Unwrapped and Wrapped. Specifications or profiles that define additional Notification Formats SHOULD define how wse:eventTypes bind to the Notifications for those formats. In the absence of a mapping for a particular Notification Format, implementations MAY provide a Notification WSDL (see below) that explicitly describes the Notification operations.

A.2.2.1 Binding for Unwrapped Notifications

TBD

A.2.2.2 Binding for Wrapped Notifications

The information about a Event Type contained in the eventType element binds to a Wrapped Notification for that type as follows:

The /soap:Envelope/soap:Body/wse:Notify/@actionURI attribute of the Wrapped Notification has the value of the actionURI attribute of the eventType element corresponding to the type of the Event being transmitted.
The /soap:Envelope/soap:Body/wse:Notify element has a single child element. This child element is an instance of the Global Element Declaration referenced by the element attribute of the eventType element corresponding to the type of the Event being transmitted.

A.3 Notification WSDLs

As described previously, Event Sources transmit Events to Event Sinks as SOAP messages called "Notifications". These Notifications MAY be described via a Web Services Definition Language [WSDL 1.1] definitions element termed a "Notification WSDL". A Notification WSDL describes the interface that the Event Sink is required to implement to receive and process the Notifications that might result from a successful Subscribe request that used a particular Format URI. Notification WSDLs contain abstract port types and concrete bindings. The port types contain operations that correspond to the Events that are transmitted. The bindings describe the Notification Formats (e.g. Unwrapped or Wrapped) for those Events. The following is an example of a Notification WSDL:

Example A-5: Notification WSDL

(01) <wsdl:definitions xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/"
(02)                   targetNamespace="http://www.example.org/oceanwatch/notifications"
(03)                   xmlns:xs="http://www.w3.org/2001/XMLSchema"
(04)                   xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/"
(05)                   xmlns:wsam="http://www.w3.org/2007/05/addressing/metadata"
(06)                   xmlns:ow="http://www.example.org/oceanwatch"
(07)                   xmlns:tns="http://www.example.org/oceanwatch/notifications">
(08)   <wsdl:types>
(09)     <xs:schema targetNamepace="http://www.example.org/oceanwatch">
(10)       <xs:include schemaLocation="http://www.example.org/schemas/oceanwatch.xsd"/>
(11)       <xs:element name="WindReport" type="ow:WindReportType">
(12)     </xs:schema>
(13)   </wsdl:types>
(14)
(15)   <wsdl:message name="WindReportNotificationMsg">
(16)     <wsdl:part name="event" element="ow:WindReport"/>
(17)   </wsdl:message>
(18)
(19)   <wsdl:portType name="WindReportPortType">
(20)     <wsdl:operation name="WindReportNotificationOp">
(21)       <wsdl:input message="tns:WindReportNotificationMsg"
(22)                  wsam:Action="http://www.example.org/oceanwatch/2003/WindReport"/>
(23)     </wsdl:operation>
(24)   </wsdl:portType>
(25)
(26)   <wsdl:binding name="WindReportBinding" type="tns:WindReportPortType">
(27)     <soap:binding style="document" transport="http://schemas.xmlsoap.org/soap/http"/>
(28)     <wsdl:operation name="WindReportNotificationOp">
(29)       <soap:operation soapAction=""/>
(30)       <wsdl:input>
(31)         <soap:body use="literal"/>
(32)       </wsdl:input>
(33)     </wsdl:operation>
(34)   </wsdl:binding>
(35) </wsdl:definitions>

The abstract portion of this Notification WSDL is in lines (08-24). The concrete binding in lines (26-34) corresponds to the Unwrapped Notification Format.

A.3.1 Retrieving Notification WSDLs

Although there are many ways in which an Event Source can make Notification WSDLs available to potential Subscribers and Event Sinks, this specification RECOMMENDS the use of the mechanisms described in WS-MetadataExchange [WS-MetadataExchange]. This specification defines the following URI to serve as the Dialect URI for the Notification WSDL.

http://www.w3.org/2009/02/ws-evt/NotificationWSDL

Because the Notification Format specified in a Subscribe request can affect various aspects of the Notification WSDL, it is necessary to correlate Notification WSDLs with their corresponding Notification Formats. When using WS-MetadataExchange to transfer Notification WSDLs, the corresponding Format URI for that Notification WSDL is represented via the @Identifier attribute.

When a mex:GetMetadata request is targeted to a Subscription Endpoint with a mex:Dialect@URI of either "http://www.w3.org/2009/02/ws-evt/NotificationWSDL" or "http://www.w3.org/2009/06/ws-mex/Dialects/ws-mex-all", the mex:Metadata element of the mex:GetMetadataResponse MAY include (in addition to other Metadata Sections that may be present) one or more Metadata Sections with a @Dialect attribute with the value of "http://www.w3.org/2009/02/ws-evt/NotificationWSDL" and a wsdl:definitions element as their dialect specific element. The value of the @Identifier attribute for these Metadata Sections MUST equal the Format URI associated with that Notification WSDL (e.g."http://www.w3.org/2009/02/ws-evt/DeliveryFormats/Unwrap"). For any particular Format URI/@Identifier, there MUST NOT exist more than one Metadata Section containing a Notification WSDL.

The following GetMetadata request, when sent to the Subscription Endpoint used in Example 2-1

Example A-6: GetMetadata Request for Notification WSDLs

(01) <s12:Envelope xmlns:s12="http://www.w3.org/2003/05/soap-envelope"
(02)                  xmlns:wsa="http://www.w3.org/2005/08/addressing"
(03)                  xmlns:wse="http://www.w3.org/2009/02/ws-evt"
(04)                  xmlns:mex="http://www.w3.org/2009/02/ws-mex">
(05)   <s12:Header>
(06)     <wsa:Action>
(07)       http://www.w3.org/2009/02/ws-mex/GetMetadata
(08)     </wsa:Action>
(09)     <wsa:MessageID>
(10)       uuid:126287f0-521d-11de-8a39-0800200c9a66
(11)     </wsa:MessageID>
(12)     <wsa:To>http://www.example.org/oceanwatch/EventSource</wsa:To>
(13)   </s12:Header>
(14)   <s12:Body>
(15)     <mex:GetMetadata>
(16)       <mex:Dialect URI="http://www.w3.org/2009/02/ws-evt/NotificationWSDL"
(17)                   Identifier="http://www.w3.org/2009/02/ws-evt/DeliveryFormats/Unwrap"/>
(18)     </mex:GetMetadata>
(19)   </s12:Body>
(20) </s12:Envelope>

returns the following GetMetadataResponse element

Example A-7: GetMetadataResponse with Notification WSDL

(01) <s12:Envelope xmlns:s12="http://www.w3.org/2003/05/soap-envelope"
(02)                  xmlns:wsa="http://www.w3.org/2005/08/addressing"
(03)                  xmlns:wse="http://www.w3.org/2009/02/ws-evt"
(04)                  xmlns:mex="http://www.w3.org/2009/02/ws-mex">
(05)   <s12:Header>
(06)     <wsa:Action>
(07)       http://www.w3.org/2009/02/ws-mex/GetMetadataResponse
(08)     </wsa:Action>
(09)     <wsa:RelatesTo>
(10)       uuid:126287f0-521d-11de-8a39-0800200c9a66
(11)     </wsa:RelatesTo>
(12)   </s12:Header>
(13)   <s12:Body>
(14)     <mex:Metadata>
(15)       <mex:MetadataSection Dialect="http://www.w3.org/2009/02/ws-evt/NotificationWSDL"
(16)                            Identifier="http://www.w3.org/2009/02/ws-evt/DeliveryFormats/Unwrap">
(17)         <wsdl:definitions xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/"
(18)                              targetNamespace="http://www.example.org/oceanwatch/notifications"
(19)                              . . . 
(20)                              xmlns:tns="http://www.example.org/oceanwatch/notifications">
(21)           <wsdl:types>
(22)             <xs:schema targetNamepace="http://www.example.org/oceanwatch">
(23)               <xs:include schemaLocation="http://www.example.org/schemas/oceanwatch.xsd"/>
(24)               <xs:element name="WindReport" type="ow:WindReportType">
(25)             </xs:schema>
(26)           </wsdl:types>
(27)
(28)           <wsdl:message name="WindReportNotificationMsg">
(29)             <wsdl:part name="event" element="ow:WindReport"/>
(30)           </wsdl:message>
(31)
(32)           . . .
(33)         </wsdl:definitions>
(34)       </mex:MetadataSection
(35)     </mex:Metadata>
(36)   </s12:Body>
(37) </s12:Envelope>

A.4 Multiple Event Information Metadata Sections

When WS-MetadataExchange [WS-MetadataExchange] is used to retrieve metadata about an Event Source, recipients of mex:Metadata elements that contain Metadata Sections with both the "http://www.w3.org/2009/02/ws-evt/EventDescriptions" and "http://www.w3.org/2009/02/ws-evt/NotificationWSDL" dialects MUST regard these Metadata Sections as relating to the same set of Events. In cases where the mex:Metadata element contains multiple Notification WSDLs (i.e. multiple Metadata Sections with a @Dialect of "http://www.w3.org/2009/02/ws-evt/NotificationWSDL"), recipients MUST similarly regard these Notification WSDLs as relating to the same set of Events although their Notification Formats differ.

B XML Schema

A normative copy of the XML Schema [XML Schema, Part 1], [XML Schema, Part 2] description for this specification may be retrieved from the following address:

http://www.w3.org/2009/02/ws-evt/eventing.xsd

A non-normative copy of the XML schema is listed below for convenience.

<xs:schema 
  targetNamespace="http://www.w3.org/2009/02/ws-evt" 
  xmlns:tns="http://www.w3.org/2009/02/ws-evt"
  xmlns:wsa="http://www.w3.org/2005/08/addressing"
  xmlns:xs="http://www.w3.org/2001/XMLSchema" 
  elementFormDefault="qualified" 
  blockDefault="#all">
  
  <xs:import 
    namespace="http://www.w3.org/XML/1998/namespace" 
    schemaLocation="http://www.w3.org/2001/xml.xsd" />
  <xs:import
    namespace="http://www.w3.org/2005/08/addressing"
    schemaLocation="http://www.w3.org/2005/08/addressing/ws-addr.xsd" />
 
  <!-- Types and global elements -->
  <xs:complexType name="DeliveryType" mixed="true">
    <xs:sequence>
      <xs:element ref="tns:NotifyTo" minOccurs="0" maxOccurs="1" />
      <xs:any namespace="##other" processContents="lax" 
              minOccurs="0" maxOccurs="unbounded" />
    </xs:sequence>
    <xs:anyAttribute namespace="##other" processContents="lax" />
  </xs:complexType>
 
  <xs:complexType name="FormatType" mixed="true">
    <xs:sequence>
      <xs:any namespace="##any" processContents="lax" 
              minOccurs="0" maxOccurs="unbounded" />
    </xs:sequence>
    <xs:attribute name="Name" type="xs:anyURI" use="optional" 
      default="http://http://www.w3.org/2009/02/ws-evt/DeliveryFormats/Unwrap" />
    <xs:anyAttribute namespace="##other" processContents="lax" />
  </xs:complexType>
 
  <xs:simpleType name="NonNegativeDurationType">
    <xs:restriction base="xs:duration">
      <xs:minInclusive value="P0Y0M0DT0H0M0S" />
    </xs:restriction>
  </xs:simpleType>
 
  <xs:simpleType name="ExpirationType">
      <xs:union memberTypes="xs:dateTime 
                tns:NonNegativeDurationType" />
  </xs:simpleType>
 
  <xs:complexType name="FilterType" mixed="true">
    <xs:sequence>
      <xs:any namespace="##other" processContents="lax" 
              minOccurs="0" maxOccurs="unbounded" />
    </xs:sequence>
    <xs:attribute name="Dialect" type="xs:anyURI" use="optional" 
      default="http://www.w3.org/TR/1999/REC-xpath-19991116" />
    <xs:anyAttribute namespace="##other" processContents="lax" />
  </xs:complexType>
 
  <xs:complexType name="LanguageSpecificStringType">
    <xs:simpleContent>
      <xs:extension base="xs:string">
        <xs:attribute ref="xml:lang" />
        <xs:anyAttribute namespace="##other" processContents="lax" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>
 
  <xs:element name="NotifyTo" type="wsa:EndpointReferenceType" />
 
  <!-- Subscribe request -->
  <xs:element name="Subscribe">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="EndTo" type="wsa:EndpointReferenceType" 
                    minOccurs="0" />
        <xs:element name="Delivery" type="tns:DeliveryType" />
        <xs:element name="Format" type="tns:FormatType" 
                    minOccurs="0" />
        <xs:element name="Expires" type="tns:ExpirationType" 
                    minOccurs="0" />
        <xs:element name="Filter" type="tns:FilterType" 
                    minOccurs="0" />
        <xs:any namespace="##other" processContents="lax" 
                minOccurs="0" maxOccurs="unbounded" />
      </xs:sequence>
      <xs:anyAttribute namespace="##other" processContents="lax" />
    </xs:complexType>
  </xs:element>
 
  <!-- Subscribe response -->
  <xs:element name="SubscribeResponse">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="SubscriptionManager" 
                    type="wsa:EndpointReferenceType" />
        <xs:element name="Expires" type="tns:ExpirationType" />
        <xs:any namespace="##other" processContents="lax" 
                minOccurs="0" maxOccurs="unbounded" />
      </xs:sequence>
      <xs:anyAttribute namespace="##other" processContents="lax" />
    </xs:complexType>
  </xs:element>
 
  <!-- Used in a fault if there's an unsupported dialect -->
  <xs:element name="SupportedDialect" type="xs:anyURI" />
 
  <!-- Used in a fault if there's an unsupported format name -->
  <xs:element name="SupportedDeliveryFormat" type="xs:anyURI" />
 
  <!-- Renew request -->
  <xs:element name="Renew">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="Expires" type="tns:ExpirationType" 
                    minOccurs="0" />
        <xs:any namespace="##other" processContents="lax" 
                minOccurs="0" maxOccurs="unbounded" />
      </xs:sequence>
      <xs:anyAttribute namespace="##other" processContents="lax" />
    </xs:complexType>
  </xs:element>
 
  <!-- Renew response -->
  <xs:element name="RenewResponse">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="Expires" type="tns:ExpirationType" 
                    minOccurs="0" />
        <xs:any namespace="##other" processContents="lax" 
                minOccurs="0" maxOccurs="unbounded" />
      </xs:sequence>
      <xs:anyAttribute namespace="##other" processContents="lax" />
    </xs:complexType>
  </xs:element>
 
  <!-- GetStatus request -->
  <xs:element name="GetStatus">
    <xs:complexType>
      <xs:sequence>
        <xs:any namespace="##other" processContents="lax" 
                minOccurs="0" maxOccurs="unbounded" />
      </xs:sequence>
      <xs:anyAttribute namespace="##other" processContents="lax" />
    </xs:complexType>
  </xs:element>
 
  <!-- GetStatus response -->
  <xs:element name="GetStatusResponse">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="Expires" type="tns:ExpirationType" 
                    minOccurs="0" />
        <xs:any namespace="##other" processContents="lax" 
                minOccurs="0" maxOccurs="unbounded" />
      </xs:sequence>
      <xs:anyAttribute namespace="##other" processContents="lax" />
    </xs:complexType>
  </xs:element>
 
  <!-- Unsubscribe request -->
  <xs:element name="Unsubscribe">
    <xs:complexType>
      <xs:sequence>
        <xs:any namespace="##other" processContents="lax" 
                minOccurs="0" maxOccurs="unbounded" />
      </xs:sequence>
      <xs:anyAttribute namespace="##other" processContents="lax" />
    </xs:complexType>
  </xs:element>
 
  <!-- Unsubscribe response -->
  <xs:element name="UnsubscribeResponse">
    <xs:complexType>
      <xs:sequence>
        <xs:any namespace="##other" processContents="lax" 
                minOccurs="0" maxOccurs="unbounded" />
      </xs:sequence>
      <xs:anyAttribute namespace="##other" processContents="lax" />
    </xs:complexType>
  </xs:element>
 
  <!-- SubscriptionEnd message -->
  <xs:element name="SubscriptionEnd">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="Status"
                    type="tns:OpenSubscriptionEndCodeType" />
        <xs:element name="Reason" 
                    type="tns:LanguageSpecificStringType" 
                    minOccurs="0" maxOccurs="unbounded" />
        <xs:any namespace="##other" processContents="lax" 
                minOccurs="0" maxOccurs="unbounded" />
      </xs:sequence>
      <xs:anyAttribute namespace="##other" processContents="lax" />
    </xs:complexType>
  </xs:element>
 
  <xs:simpleType name="SubscriptionEndCodeType">
    <xs:restriction base="xs:anyURI">
      <xs:enumeration value=
  "http://www.w3.org/2009/02/ws-evt/DeliveryFailure" />
      <xs:enumeration value=
  "http://www.w3.org/2009/02/ws-evt/SourceShuttingDown" />
      <xs:enumeration value=
  "http://www.w3.org/2009/02/ws-evt/SourceCancelling" />
    </xs:restriction>
  </xs:simpleType>
 
  <xs:simpleType name="OpenSubscriptionEndCodeType">
    <xs:union memberTypes="tns:SubscriptionEndCodeType xs:anyURI" />
  </xs:simpleType>
    
  <!-- RetryAfter Fault Detail Element -->
  <xs:element name="RetryAfter"  type="tns:RetryAfterType"/>
  <xs:complexType name="RetryAfterType">
    <xs:simpleContent>
      <xs:extension base="xs:nonNegativeInteger">
        <xs:anyAttribute namespace="##other" processContents="lax" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>
     
  <xs:attribute name="EventSource" type="xs:boolean" />

  <!-- Wrapped Events -->
  <xs:complexType name="EventType" mixed="true">
    <xs:sequence>
      <xs:any namespace="##any" processContents="lax" minOccurs="0"
              maxOccurs="unbounded"/>
    </xs:sequence>
    <xs:attribute name="actionURI" type="xs:anyURI" use="optional" />
    <xs:anyAttribute namespace="##other" processContents="lax" />
  </xs:complexType>
  <xs:element name="Notify" type="tns:EventType" />

</xs:schema>

C WSDL

A normative copy of the WSDL [WSDL 1.1] description can be retrieved from the following address:

http://www.w3.org/2009/02/ws-evt/eventing.wsdl

A non-normative copy of the WSDL description is listed below for convenience.

<wsdl:definitions
  targetNamespace="http://www.w3.org/2009/02/ws-evt"
  xmlns:wsa="http://www.w3.org/2005/08/addressing"
  xmlns:wsam="http://www.w3.org/2007/05/addressing/metadata"
  xmlns:wse="http://www.w3.org/2009/02/ws-evt" 
  xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/" 
  xmlns:xs="http://www.w3.org/2001/XMLSchema" >

  <wsdl:types>
    <xs:schema>
       <xs:import
         namespace="http://www.w3.org/2009/02/ws-evt"
         schemaLocation=
  "http://www.w3.org/2009/02/ws-evt/eventing.xsd" />
    </xs:schema>
  </wsdl:types>
  
  <wsdl:message name="SubscribeMsg" >
    <wsdl:part name="body" element="wse:Subscribe" />
  </wsdl:message>
  <wsdl:message name="SubscribeResponseMsg" >
    <wsdl:part name="body" element="wse:SubscribeResponse" />
  </wsdl:message>
  
  <wsdl:message name="RenewMsg" >
    <wsdl:part name="body" element="wse:Renew" />
  </wsdl:message>
  <wsdl:message name="RenewResponseMsg" >
    <wsdl:part name="body" element="wse:RenewResponse" />
  </wsdl:message>
  
  <wsdl:message name="GetStatusMsg" >
    <wsdl:part name="body" element="wse:GetStatus" />
  </wsdl:message>
  <wsdl:message name="GetStatusResponseMsg" >
    <wsdl:part name="body" element="wse:GetStatusResponse" />
  </wsdl:message>
  
  <wsdl:message name="UnsubscribeMsg" >
    <wsdl:part name="body" element="wse:Unsubscribe" />
  </wsdl:message>
  <wsdl:message name="UnsubscribeResponseMsg" >
    <wsdl:part name="body" element="wse:UnsubscribeResponse" />
  </wsdl:message>
 
  <wsdl:message name="SubscriptionEnd" >
    <wsdl:part name="body" element="wse:SubscriptionEnd" />
  </wsdl:message>

  <message name="notifyEvent">
    <part name="parameter" element="tns:Notify"/>
  </message>
  
  <wsdl:portType name="EventSource" >
    <wsdl:operation name="SubscribeOp" >
      <wsdl:input 
        message="wse:SubscribeMsg"
        wsam:Action="http://www.w3.org/2009/02/ws-evt/Subscribe"/>
      <wsdl:output 
        message="wse:SubscribeResponseMsg" 
        wsam:Action="http://www.w3.org/2009/02/ws-evt/SubscribeResponse"/>
    </wsdl:operation>
  </wsdl:portType>
  
  <wsdl:portType name="SubscriptionEndPortType" >
    <wsdl:operation name="SubscriptionEnd" >
      <wsdl:input 
        message="wse:SubscriptionEnd" 
        wsam:Action="http://www.w3.org/2009/02/ws-evt/SubscriptionEnd"/>
    </wsdl:operation>
  </wsdl:portType>
  
  <wsdl:portType name="SubscriptionManager" >
    <wsdl:operation name="RenewOp" >
      <wsdl:input 
        message="wse:RenewMsg" 
        wsam:Action="http://www.w3.org/2009/02/ws-evt/Renew"/>
      <wsdl:output 
        message="wse:RenewResponseMsg" 
        wsam:Action="http://www.w3.org/2009/02/ws-evt/RenewResponse"/>
    </wsdl:operation>
    <wsdl:operation name="GetStatusOp" >
      <wsdl:input 
        message="wse:GetStatusMsg"
        wsam:Action="http://www.w3.org/2009/02/ws-evt/GetStatus"/>
      <wsdl:output 
        message="wse:GetStatusResponseMsg" 
        wsam:Action="http://www.w3.org/2009/02/ws-evt/GetStatusResponse"/>
    </wsdl:operation>
    <wsdl:operation name="UnsubscribeOp" >
      <wsdl:input 
        message="wse:UnsubscribeMsg" 
        wsam:Action="http://www.w3.org/2009/02/ws-evt/Unsubscribe"/>
      <wsdl:output 
        message="wse:UnsubscribeResponseMsg" 
        wsam:Action="http://www.w3.org/2009/02/ws-evt/UnsubscribeResponse"/>
    </wsdl:operation>
  </wsdl:portType>

  <portType name="WrappedSinkPortType">
    <operation name="NotifyEvent">
      <input message="tns:notifyEvent" name="NotifyEvent" 
        wsam:Action="http://www.w3.org/2009/02/ws-evt/WrappedSinkPortType/NotifyEvent"/>
    </operation>
  </portType>
</wsdl:definitions>

D WSDL for Standard Wrapped Delivery

If an Event Subscriber specifies the wrapped event delivery format http://www.w3.org/2009/02/ws-evt/DeliveryFormats/Wrap in the Subscribe request message, then the Event Sink MUST implement the following abstract WSDL and the Event Source MUST send the Notification messages wrapped in the element defined in the WSDL.

<definitions 
  xmlns="http://schemas.xmlsoap.org/wsdl/" 
  xmlns:xs="http://www.w3.org/2001/XMLSchema" 
  xmlns:wsam="http://www.w3.org/2007/05/addressing/metadata"
  xmlns:wsa="http://www.w3.org/2005/08/addressing/"
  xmlns:tns="http://www.w3.org/2009/02/ws-evt" 
  targetNamespace="http://www.w3.org/2009/02/ws-evt">
  
  <types>
    <xs:schema 
        targetNamespace="http://www.w3.org/2009/02/ws-evt">

      <xs:complexType name="EventType" mixed="true"> 
        <xs:sequence> 
          <xs:any namespace="##any" processContents="lax" minOccurs="0"
                  maxOccurs="unbounded"/> 
        </xs:sequence> 
        <xs:attribute name="actionURI" type="xs:anyURI" use="optional" /> 
        <xs:anyAttribute namespace="##other" processContents="lax" /> 
      </xs:complexType> 

      <xs:element name="Notify" type="tns:EventType" />
    </xs:schema>
  </types>
  
  <message name="notifyEvent">
    <part name="parameter" element="tns:Notify"/>
  </message>
  
  <portType name="WrappedSinkPortType">
    <operation name="NotifyEvent">
      <input message="tns:notifyEvent" name="NotifyEvent" 
        wsam:Action="http://www.w3.org/2009/02/ws-evt/WrappedSinkPortType/NotifyEvent"/>
    </operation>
  </portType>
</definitions>

E XML Schema for EventDescriptions

A normative copy of the XML Schema [XML Schema, Part 1], [XML Schema, Part 2] description for the EventDescriptions element may be retrieved from the following address:

http://www.w3.org/2009/02/ws-evt/EventDescriptions.xsd

A non-normative copy of the XML schema is listed below for convenience.

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
           targetNamespace="http://www.w3.org/2009/02/ws-evt"
           elementFormDefault="qualified" attributeFormDefault="unqualified">
  <xs:element name="EventDescriptions">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="types">
          <xs:annotation>
            <xs:documentation>Data type definitions that are relevant to described notifications.</xs:documentation>
          </xs:annotation>
          <xs:complexType>
            <xs:sequence>
              <xs:any namespace="##other" minOccurs="0" maxOccurs="unbounded"/>
            </xs:sequence>
            <xs:anyAttribute namespace="##other" processContents="lax"/>
          </xs:complexType>
        </xs:element>
        <xs:element name="eventType" maxOccurs="unbounded">
          <xs:complexType>
            <xs:sequence>
              <xs:any namespace="##other" minOccurs="0" maxOccurs="unbounded"/>
            </xs:sequence>
            <xs:attribute name="name" type="xs:NCName" use="required"/>
            <xs:attribute name="element" type="xs:QName" use="required"/>
            <xs:attribute name="action" type="xs:anyURI" use="required"/>
            <xs:anyAttribute namespace="##other" processContents="lax"/>
          </xs:complexType>
        </xs:element>
        <xs:any namespace="##other" minOccurs="0" maxOccurs="unbounded"/>
      </xs:sequence>
      <xs:attribute name="targetNamespace" type="xs:anyURI" use="required"/>
      <xs:anyAttribute namespace="##other" processContents="lax"/>
    </xs:complexType>
  </xs:element>
</xs:schema>

F Change Log

Data	Author	Description
2009/03/04	DD	Added resolution of issue 6391
2009/03/04	DD	Added resolution of issue 6519
2009/03/04	DD	Added resolution of issue 6427
2009/03/04	DD	Added resolution of issue 6459
2009/03/09	DD	Added resolution of issue 6397
2009/03/09	DD	Added resolution of issue 6426
2009/03/11	DD	Added change log
2009/03/11	DD	Added resolution of issue 6641
2009/03/11	DD	Added resolution of issue 6498
2009/03/11	DD	Added resolution of issue 6425
2009/03/16	KW	Added resolution of issue 6587
2009/03/17	KW	Added resolution of issue 6400
2009/03/17	DD	Added resolution of issue 6428
2009/03/17	DD	Added resolution of issue 6687
2009/03/23	DD	Added resolution of issue 6666
2009/03/23	DD	Added resolution of issue 6681
2009/03/24	DD	Added resolution of issue 6595
2009/03/24	DD	Added resolution of issue 6648
2009/04/07	DD	Added resolution of issue 6727
2009/04/07	DD	Added resolution of issue 6725
2009/04/07	DD	Added resolution of issue 6715
2009/04/22	KW	Added resolution of issue 6739
2009/04/28	DD	Added resolution of issue 6787
2009/04/28	DD	Added resolution of issue 6788
2009/05/13	KW	Added resolution of issue 6472
2009/05/13	DD	Added resolution of issue 6850
2009/05/13	DD	Added resolution of issue 6696
2009/05/19	DD	Added resolution of issue 6907
2009/05/19	DD	Added resolution of issue 6429
2009/05/21	DD	Added resolution of issue 6674
2009/05/27	DD	Added resolution of issue 6906
2009/06/04	DD	Added resolution of issue 6955
2009/06/04	DD	Added resolution of issue 6916
2009/06/04	DD	Added resolution of issue 6986
2009/07/07	DD	Added resolution of issue 7039
2009/07/21	DD	Added resolution of issue 6980
2009/07/28	DD	Added resolution of issue 6692
2009/08/04	DD	Added resolution of issue 7136