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RE: Collections and Request-URIs

From: Julian Reschke <julian.reschke@gmx.de>
Date: Tue, 18 Jun 2002 18:52:55 +0200
To: "Jim Luther" <luther.j@apple.com>, <w3c-dist-auth@w3c.org>
Message-ID: <JIEGINCHMLABHJBIGKBCAEKFEMAA.julian.reschke@gmx.de>

Hi,

just did a few tests:

- Adobe Golive follows the 301 redirect without asking the user
- XML Spy always submits the folder URL without trailing / (no matter what
you enter), and reports the 301 as error

Also interesting:

- the default config for Apache 2.0.36 disables this behaviour for both the
Microsoft webfolder client and the WebDrive client:

# The following directive disables redirects on non-GET requests for
# a directory that does not include the trailing slash.  This fixes a
# problem with Microsoft WebFolders which does not appropriately handle
# redirects for folders with DAV methods.
#
BrowserMatch "Microsoft Data Access Internet Publishing Provider"
redirect-carefully
BrowserMatch "^WebDrive" redirect-carefully

> -----Original Message-----
> From: w3c-dist-auth-request@w3.org
> [mailto:w3c-dist-auth-request@w3.org]On Behalf Of Jim Luther
> Sent: Tuesday, June 18, 2002 1:46 AM
> To: w3c-dist-auth@w3c.org
> Subject: Collections and Request-URIs
>
>
>
> RFC 2518, section 5.2 says:
>
> "There is a standing convention that when a collection is referred to by
> its name without a trailing slash, the trailing slash is automatically
> appended.  Due to this, a resource may accept a URI without a
> trailing "/" to point to a collection. In this case it SHOULD return a
> content-location header in the response pointing to the URI ending with
> the "/". For example, if a client invokes a method on
> http://foo.bar/blah (no trailing slash), the resource
> http://foo.bar/blah/ (trailing slash) may respond as if the operation
> were invoked on it, and should return a content-location header with
> http://foo.bar/blah/ in it.  In general clients SHOULD use the "/" form
> of collection names."
>
> It looks to me like the "standing convention" doesn't match the BNF. RFC
> 2616, section 5.1.2 gives this rule for the Request-URI in the
> Request-Line:
>
> 	Request-URI 	= "*" | absoluteURI | abs_path | authority
>
> and RFC 2396, section 3 gives these rules for abs_path and path_segments:
>
> 	abs_path      = "/"  path_segments
> 	path_segments = segment *( "/" segment )
>
> So by my reading, abs_path should not have a trailing slash. Did I miss
> something? If not, I think the WebDAV spec should say that servers MUST
> handle Request-URIs to collections without the trail slash.
>
>
> Anyway, trailing slashes issue causes an interoperability problem for
> our WebDAV file system and Apache 2.0 servers.  Since Mac OS X's WebDAV
> file system doesn't know if the end path component passed to it is a
> collection or non-collection resource, it doesn't put a trailing slash
> on the Request-URI. This works on all servers except for Apache 2 which
> sends us a "301 Moved Permanently" response. We don't redirect because
> the HTTP spec (RFC 2616, section 10.3.2) says:
>
> "If the 301 status code is received in response to a request other than
> GET or HEAD, the user agent MUST NOT automatically redirect the request
> unless it can be confirmed by the user, since this might change the
> conditions under which the request was issued."
>
> Hmmm... WebDAV file system can't confirm it with the user because it's a
> file system which doesn't do user interaction. I guess that I could
> compare the URI in the 301 response to see if it's the same as what I
> sent except for the trailing slash and retry the request. However, that
> would double the number of PROPFIND for collection transactions we send
> to Apache 2 servers and I'm trying to cut the number of transactions
> >from our client, not increase them.
>
> Apparently, Microsoft WebFolders had the same problem with Apache 2.
> Here's what we found in httpd.conf:
>
> 	#
> 	# The following directive disables redirects on non-GET requests for
> 	# a directory that does not include the trailing slash.
> This fixes a
> 	# problem with Microsoft WebFolders which does not
> appropriately handle
> 	# redirects for folders with DAV methods.
> 	#
> 	BrowserMatch "Microsoft Data Access Internet Publishing Provider"
> redirect-carefully
> 	BrowserMatch "^WebDrive" redirect-carefully
>
> So if we add a similar line:
>
> 	BrowserMatch "^WebDAVFS" redirect-carefully
>
> to Apache's httpd.conf file to do a redirect-carefully for our
> User-Agent, our client works great with Apache 2 DAV servers.
>
> - Jim Luther
>
Received on Tuesday, 18 June 2002 12:53:28 GMT

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