Client Web Browser Behavior When Handling 301 Redirect
- by Jon Swanson
The RFC seems to suggest that the client should permanently cache the response:
http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html
10.3.2 301 Moved Permanently
The requested resource has been
assigned a new permanent URI and any
future references to this resource
SHOULD use one of the returned URIs.
Clients with link editing capabilities
ought to automatically re-link
references to the Request-URI to one
or more of the new references returned
by the server, where possible. This
response is cacheable unless indicated
otherwise.
The new permanent URI SHOULD be given
by the Location field in the response.
Unless the request method was HEAD,
the entity of the response SHOULD
contain a short hypertext note with a
hyperlink to the new URI(s).
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.
Note: When automatically redirecting a POST request after
receiving a 301 status code, some existing HTTP/1.0 user agents
will erroneously change it into a GET request.
I'm having a hard time finding concrete browser documentation for any major browser that states how they handle these.
I've started digging through the source code of firefox, but quickly got lost.
Is the following scenario true for which (if any) browsers, and is there definitive documentation for either Firefox or IE that states as much?:
First Time Around:
1.1: User enters link to site A, or clicks on a link directed at Site A
1.2: Browser interprets link at Site A, first time, no cache. Sends GET to Site A.
1.2: Site A responds with 301 Redirect to Site B
1.3: Browser sends GET to Site B.
Any Subsequent Times Around:
2.2: User clicks on a link directed at Site A
2.2: Browser sees that, due to a past 301 redirect, Site A should now be Site B.
2.3: Without initiating any request whatsoever at Site A, browser initiates GET at Site B.
