Do I need to use http redirect code 302 or 307?

Question

Suppose I have a page on my website to show media releases for the current month
http://www.mysite.com/mediareleases.aspx

And for reasons which it's mundane to go into*, this page MUST be given a query string with the current day of the month in order to produce this list:
http://www.mysite.com/mediareleases.aspx?prevDays=18

As such I need to redirect clients requesting http://www.mysite.com/mediareleases.aspx to http://www.mysite.com/mediareleases.aspx?prevDays=whateverDayOfTheMonthItIs

My question is, if I want google to index the page without the query parameter, should I use status code 302 or 307 to perform the redirect?

Both indicate that the page has "temporarily" moved - which is what I want because the page "moves" every day if you get my meaning.

[*] I'm using a feature of a closed-source .NET CMS so my hands are tied.

Answer 1

I feel your pain. As for a solution, it's hard to say what search engines will do. It seems that each one has its own way of handling redirects. This link suggests that a 302 will index the contents of the redirected page but still use the main page link, but it's not clear what a 307 will do.

Another way you could consider proceeding is with a javascript redirect and a <noscript> tag explaining what's going on. That will also foul up non-javascript browsers, and you'd have to proceed with caution to avoid Google's sneaky-site detection routine, but I suspect that as long as your noscript contains a hyperlink that matches the new URL you'd be OK.

Either way I'd still pursue doing a purely server-side request if at all possible. Heck, if your expected traffic is light, you could treat your home page as a proxy in the case where there's no querystring. Have it use a background thread to request itself with the querystring and pipe out the results. :-)

edit just saw you're using .NET. Maybe consider this answer from SO: http://stackoverflow.com/questions/323265/c-can-i-modify-request-forms-variables .

Answer 2

Google's documentation seems to indicate that both 302 and 307 are treated equivalently, and that "Googlebot will continue to crawl and index the original location."

But in the face of ambiguity, you might as well dig into the RFCs and try to do the Right Thing, with the naïve hope that the crawlers will do the same. In this case, RFC 2616 § 10.3 contains nearly identical definitions for each response code, with one exception:

302: Since the redirection might be altered on occasion, the client SHOULD continue to use the Request-URI for future requests.

307: Since the redirection MAY be altered on occasion, the client SHOULD continue to use the Request-URI for future requests.

Which does not strike me as a significant distinction. My reading is that 302 instructs clients that webmasters are untrustworthy, and 307 explicitly tells webmasters that clients will not trust them, so they may freely alter the redirect.

I think the more telling point is the note in 302's definition:

Note: RFC 1945 and RFC 2068 specify that the client is not allowed to change the method on the redirected request. However, most existing user agent implementations treat 302 as if it were a 303 response, performing a GET on the Location field-value regardless of the original request method. The status codes 303 and 307 have been added for servers that wish to make unambiguously clear which kind of reaction is expected of the client.

Which, to me, indicates that 302 and 307 are largely equivalent, but that HTTP/1.0 clients failed to implement 302 correctly the first time around.