W3C home > Mailing lists > Public > uri@w3.org > April 2005

Re: I-D ACTION:draft-duerst-mailto-bis-00.txt

From: Martin Duerst <duerst@it.aoyama.ac.jp>
Date: Sat, 09 Apr 2005 20:21:19 +0900
Message-Id: <6.0.0.20.2.20050409201706.0902ea30@itmail.it.aoyama.ac.jp>
To: uri@w3.org

Hello Bruce,

Many thanks for your extensive comments. I have to apologize
for not having integrated your earlier comments on the current
mailto RFC; this is on my list of things to do. Unfortunately,
I have changed jobs at the start of April, and am very busy,
so I may not get to it for a while.

Regards,    Martin.

P.S.: When sending comments about a draft, I suggest you copy
       the authors; this significantly increases the chance that
       they get considered.

At 03:55 05/04/09, Bruce Lilly wrote:
 >
 >On Wed February 16 2005 10:20, Internet-Drafts@ietf.org wrote:
 >> A New Internet-Draft is available from the on-line Internet-Drafts 
directories.
 >>
 >>
 >> 	Title		: The mailto URI scheme
 >> 	Author(s)	: M. Duerst, L. Masinter
 >> 	Filename	: draft-duerst-mailto-bis-00.txt
 >> 	Pages		: 13
 >> 	Date		: 2005-2-15
 >
 >Comments:
 >
 >The Abstract states "for designating electronic mail addresses", the
 >section 1 text states "the Internet mailing address of an individual or
 >service", section 3 says "an internet resource", and the reality seems
 >to be specification of a prototype internet message (RFCs 822, 2822) as
 >alluded to briefly in draft section 8.  Claims regarding the purpose of
 >a mailto URI should be consistent.
 >
 >Section 1 claims that "a previous version of the mailto URI scheme had
 >severe limitations for non-ASCII characters", which is untrue; RFC 2047
 >mechanisms which (as amended by errata and RFC 2231) provide not only
 >for non-ASCII text but also for language tagging as required by RFC
 >2277 for text.
 >
 >The UTF-8 scheme presented is claimed as "more straightforward and
 >consistent internationalization", but it is not backwards compatible
 >with existing implementations and fails to provide any mechanism for
 >language tagging as required by BCP 18.  When foisted upon existing
 >mailto URI parsers, illegal message content will be generated, causing
 >loss of interoperability due to the lack of backwards compatibility of
 >that provision in the draft under discussion.
 >
 >Section 2 ABNF uses "urlc", which is not defined anywhere.  Note that
 >per http://www.ietf.org/ID-Checklist.html, all ABNF is supposed to be
 >checked for such errors.  The text implies that "mailbox" and "address"
 >per RFC 2822 are equivalent, whereas they are defined quite differently
 >in that RFC; moreover, the field body of an RFC 2822 To field is an
 >address-list, which is not mentioned in the draft under discussion.
 >Text states that "reserved" characters must be encoded, but does not
 >give a list of "reserved" characters or a reference.  RFC 3986 (listed
 >as a normative reference, but not specifically mentioned w.r.t.
 >"reserved") defines URI reserved characters as:
 >      reserved    = gen-delims / sub-delims
 >
 >      gen-delims  = ":" / "/" / "?" / "#" / "[" / "]" / "@"
 >
 >      sub-delims  = "!" / "$" / "&" / "'" / "(" / ")"
 >                  / "*" / "+" / "," / ";" / "="
 >The draft text specifically mentions "parentheses, comma, and the
 >percent sign" as common in mailbox syntax; parentheses and comma are
 >forbidden in a mailbox (they are RFC 822/2822 "specials"), percent is
 >not "reserved" (but has other issues in URIs) and is rather uncommon in
 >mailboxes, and the required '@' character which appears in every
 >address-list is not mentioned and is not encoded in the examples.  And
 >square brackets ('[' and ']') are explicitly used in doamin literals
 >which may be used in the domain of a mailbox.  Colon appears in the RFC
 >822/2822 syntax of addresses which are named groups, and appear in the
 >route portion of RFC 822 route-addrs.  Forward slashes appear in X.400
 >derived mailboxes, and '!' can appear in local-parts (RFC 976).
 >Finally, '<' and '>' are specials explicitly used in RFC 822/2822
 >angle-addrs (which may appear in mailboxes and addresses); while these
 >are not "reserved", they may not appear (unencoded) in URIs.  I believe
 >that the '@' "reserved" character issue w.r.t. encodong has recently
 >been discussed at length w.r.t. RFC 2368.  Percent-encoding is
 >recommended for non-ASCII octets, but that is incompatible with
 >existing mailto URI-to-message prototype implementations, and will
 >result in illegal and incompatible content in the resulting message
 >prototypes.  There is some wishy-washy wording about "wish to
 >maximize interoperability"; the simple fact is that the proposed
 >change is not backwards compatible, full stop.  The topic is carried
 >to ridiculous extremes by requiring developers to implement something
 >which is nowhere defined (paragraph labeled "3." (especially see the
 >last sentence in that paragraph).
 >
 >Non-standard terminology which is inconsistent with standard
 >terminology as defined and used in normative references (esp. RFC 2822)
 >appears in the draft (except, curiously, in the second paragraph of
 >draft section 3, which does use standard terminology).  E.g. instead of
 >"header name", the standard term is "header field name" or "field name"
 >(RFC 2822 section 2.2).
 >
 >The draft uses "body" in the same syntax as would be used for a
 >header field name, but lacks any indication of how a generator or
 >parser is supposed to differentiate message body from a header field
 >named "Body", nor is there a message header field name registration
 >template (BCP 90) reserving the header field name "Body".  Message
 >header field names are comprised of printing characters excluding
 >colon, and can therefore include characters such as '?', '=', and '&'.
 >The draft does not specifically discuss how those or "reserved"
 >characters are to be handled when they appear within a header field
 >name (as opposed to parts of a mailto URI intended to be part of a
 >field body or message body).
 >
 >The draft seems to have a number of formatting/content anomalies:
 >
 >idnits reports:
 >
 >  * The document seems to lack an RFC 3978 Section 5.1 IPR Disclosure
 >Acknowledgement .
 >  * There are 52 instances of too long lines in the document, the longest
 >one being 5 characters in excess of 72.
 >[...]
 >  - Line 140 has weird spacing: '..." hname  is...'
 >  - Line 161 has weird spacing: '...hvalues  encod...'
 >
 >There are also 3 empty lines following the formfeed after the last
 >page (nothing is supposed to follow that formfeed character).
 >
 >The examples at the end of section 2 do not meet syntax requirements;
 >in particular the address-lists do not meet RFC 2822 syntax
 >requirements as specified at the beginning of draft section 2 ("addr1",
 >for example, is not a valid RFC 2822 address (or mailbox)).
 >
 >Specification revisions, such as those proposed in the draft under
 >discussion, should ideally be designed in a backwards compatible
 >fashion.  When that is not possible, a "flag day" for universal change
 >form the "old" to "new" format may be specified.  Flag days are highly
 >undesirable due to the disruption caused.  The draft does something
 >much worse; it requires a non-specific, poorly defined flag day: "once
 >it is well deployed in software" (draft section 6).  No mechanism is
 >defined for determining precisely when that flag day is to take place.
 >
 >The examples in section 7.1 are bracketed with less-than and
 >greater-than symbols, unlike the examples in earlier draft sections.
 >The examples fail to percent-encode "reserved" characters as required
 >by earlier provisions in the draft. Section 7.2 compounds inconsistency
 >by returning to unbracketed examples. The first example in 7.2 will
 >result in illegal content with existing, deployed mailto URI handlers.
 >The second and third examples fail to percent-encode "reserved"
 >characters.  The fourth example will also result in illegal content
 >with existing, deployed, mailto URI handlers; moreover, the draft
 >implies that header fields which are NOT specified in the mailto URI
 >are magically generated (Content-Type and Content-Transfer-Encoding
 >fields are presented as having resulted from the example, but are
 >nowhere specified in that example).  It is unclear how the supposed
 >determination of media type was made; for all I know, the content
 >might have been intended by the mailto URI generator as describing
 >a message body with media type image/png.  The Subject field in the
 >message prototype shows a charset specified, but the mailto URI
 >specifies no such charset, and there is no indication of language.
 >It is unclear how the Content-Transfer-Encoding field was created
 >out of thin air, nor why quoted-printable (vs. base64) encoding
 >was specified.  The remaining examples in the section have similar
 >issues.
 >
 >Draft section 8 contains the incomprehensible text "of what is will be
 >sent".  Section 8 also states that "MIME header[ field]s" are
 >inappropriate, despite the fact that earlier examples use them
 >(apparently generated from thin air).  That text also mentions
 >"Apparently-To", but there is no such message header field (RFC 4021).
 >
 >The same section mentions "SMTP 'Form' address", but it is unclear what
 >that is supposed to mean (perhaps the SMTP envelope return path as
 >specified as the SMTP MAIL FROM command argument, which is used for
 >delivery notifications?).
 >
 >The last sentence of that section says "[RFC3490], and also apply".
 >And what?
 >
 >The IANA Considerations section has no mention of registration of
 >a message header field name "Body" (see above).
 >
 >There is no indication in the draft announcement, the draft heading, or
 >in the draft Abstract of the intended status sought for this draft. The
 >substantial changes proposed in the draft as currently written (viz.
 >UTF-8 not encoded per RFCs 2047/2231 and errata) would preclude
 >advancement to Draft status if they remain, but Draft status might be
 >feasible w/o those incompatible changes (of course draft status would
 >require a separate enumeration of at least two interoperable and
 >independent implementations which fully conform with all provisions
 >of the specification).
 >
 >Some issues reported regarding RFC 2368 remain unaddressed by the draft
 >under discussion:
 >
 >The syntax permits some constructs corresponding to peculiar messages,
 >e.g. a completely empty specification (save for "mailto:"), message
 >body without any header fields.  While it may be difficult or
 >impractical to prevent some of that via ABNF, the normative text
 >should probably warn against naive implementations that might
 >generate invalid messages.
 >
 >   Within mailto URLs, the characters "?", "=", "&" are reserved.
 >
 >As with URL reserved characters, there does not appear to be any
 >technical requirement to reserve all three of those characters in
 >all parts of a mailto URL. For example, neither "=" nor "&" should
 >cause trouble in the "to" part of a mailto URL. Likewise "?" should
 >be safe in "header". 
Received on Monday, 11 April 2005 00:56:19 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 6 January 2015 21:25:09 UTC