I was wondering whether search engines respect the HTTP header field Content-Location.
This could be useful, for example, when you want to remove the session ID argument out of the URL:
GET /foo/bar?sid=0123456789 HTTP/1.1
Host: example.com
…
HTTP/1.1 200 OK
Content-Location: http://example.com/foo/bar
…
Clarification:
I don’t want to redirect the request, as removing the session ID would lead to a completely different request and thus probably also a different response. I just want to state that the enclosed response is also available under its “main URL”.
Maybe my example was not a good representation of the intent of my question. So please take a look at What is the purpose of the HTTP header field “Content-Location”?.
I think Google just announced the answer to my question: the canonical link relation for declaring the canonical URL.
Maile Ohye from Google wrote:
MickeyC said...
You should have used the Content-Location header instead, as per:
http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
"14.14 Content-Location"@MikeyC: Yes, from a theoretical standpoint that makes sense and we certainly considered it. A few points, however, led us to choose :
Our data showed that the "Content-Location" header is configured improperly on many web sites. Sometimes webmasters provide long, ugly URLs that aren’t even duplicates -- it's probably unintentional. They're likely unaware that their webserver is even sending the Content-Location header.
It would've been extremely time consuming to contact site owners to clean up the Content-Location issues throughout the web. We realized that if we started with a clean slate, we could provide the functionality more quickly. With Microsoft and Yahoo! on-board to support this format, webmasters need to only learn one syntax.
Often webmasters have difficulty configuring their web server headers, but can more easily change their HTML. rel="canonical" seemed like a friendly attribute.