Bug #8017 Updated: PHP ignores "If-Modified-Since" headers

ID: 8017 Updated by: jr-php@quo.to Reported By: jr-php@quo.to -Status: Closed +Status: Open Bug Type: Feature/Change Request Operating System: Linux PHP Version: 4.2.1 New Comment: > What kind of logic do you suggest PHP should use to > determine whether the output of your script has indeed been > modified since the IMS date sent by the user agent? Easy - compare any Last-Modified header against any If-Modified-Since request header. Just like Apache does when running any CGI script (be it PHP, Perl, Python, sh, or whatever). See the past discussion on the mailing list: http://marc.theaimsgroup.com/?t=97544892600002&r=1&w=2 http://marc.theaimsgroup.com/?t=97551909500005&r=1&w=2 And specifically, the little patch I posted: http://marc.theaimsgroup.com/?l=php-dev&m=97553565420685&w=2 Granted, the Apache-specific ap_parseHTTPdate() call needs to be replaced with a portable PHP equivalent, but the patch proves that is indeed possible, and quite easy to do. Again, all I'm suggesting is making If-Modified-Since headers be handled automatically *in the same manner* as CGI scripts. *Nothing more.* I don't really see a valid reason why mod_php PHP scripts shouldn't get If-Modified-Since handling by default, when CGI PHP scripts do. It is inconsistent. > As for www.php.net not returning 304 for you -- I have no clue what www.php.net is doing these days, and it's not relevant anyway. > Please check your user agent behaviour before concluding > that this is a bug in PHP. It is not and never was my "conclusion" that this is a bug in PHP. Notice the category is "feature/change request". Previous Comments: ------------------------------------------------------------------------ [2002-06-18 04:12:40] markonen@php.net What kind of logic do you suggest PHP should use to determine whether the output of your script has indeed been modified since the IMS date sent by the user agent? Hint: we don't cache script output internally, so there is NO WAY for us to do that. As for www.php.net not returning 304 for you -- tough. It works for us. Some Internet Explorer versions have the unfortunate tendency of mangling the IMS date (ie. the IMS date is not the same as the Last-Modified date the UA received). Because we follow the RFC 2616 recommendation of checking for an exact match between the IMS date and our internal Last-Modified date, the IMS negotiation mechanism we have in place for www.php.net doesn't work on such user agents. Please check your user agent behaviour before concluding that this is a bug in PHP. ------------------------------------------------------------------------ [2002-06-17 14:00:12] jr-php@quo.to (Changing back to 'Open' since you clearly misunderstood the request.) > as PHP itself can't know what the data you are > going to produce looks like or whether it has > changed since the last request in advance > without executing your code This is not about suppressing the execution of code. It's about PHP (mod_php) handling If-Modified-Since automatically in the same manner as CGI on Apache. This is possible, too, because I posted a proof-of-concept patch to the list. > PS: whatever the CGI script you are refering to > does, i'm rather sure that it deals with that > itself, too You're saying my 5 line /bin/sh CGI script somehow "deals" with If-Modified-Since headers? I think not... ------------------------------------------------------------------------ [2002-06-17 13:20:48] hholzgra@php.net it is in the responsibility of the application code to check for If-Modified-Since conditions and to send 304 Status codes, as PHP itself can't know what the data you are going to produce looks like or whether it has changed since the last request in advance without executing your code PS: whatever the CGI script you are refering to does, i'm rather sure that it deals with that itself, too ------------------------------------------------------------------------ [2000-11-29 11:57:24] stas@php.net moved to feature request ------------------------------------------------------------------------ [2000-11-29 11:52:34] jr-php@quo.to Closed since it doesn't appear to be a bug, but rather missing functionality in PHP. ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at http://bugs.php.net/8017 -- Edit this bug report at http://bugs.php.net/?id=8017&edit=1