如何为jpeg图像设置默认响应头

Question

Ok so I have read a little about mod_headers however I have seen no definintive code to put in htaccess or anywhere else as for what to use in order to add the default response headers of Last-modified and Content-length to my jpeg images that other webites grab from me. Without these they cant check whether or not to download the entire image again or not. Any ideas? Thanks!

Answer 1

"Content-Length" is set automatically. At first remove "Last-Modified" and append a new one. Works only in .htaccess if allowed.

<FilesMatch "\.(jpg|jpeg)$">
    Header unset Last-Modified
    Header append Last-Modified "Fri, 01 Mar 2012 12:00:00 GMT"
</FilesMatch>

Another option is to adapt a caching interval.

<IfModule mod_expires.c>
    ExpiresActive on
    # on access
    ExpiresByType image/jpg "access plus 1 month"
    ExpiresByType image/jpeg "access plus 1 month"
    # or on modification
    ExpiresByType image/jpg "modification plus 1 month"
    ExpiresByType image/jpeg "modification plus 1 month"
</IfModule>

I would prefer the caching on access combined with "Last-Modified".

<FilesMatch "\.(jpg|jpeg)$">
    <IfModule mod_expires.c>
        ExpiresActive on
        ExpiresByType image/jpg "access plus 1 month"
        ExpiresByType image/jpeg "access plus 1 month"
    </IfModule>
    Header unset Last-Modified
    Header append Last-Modified "Fri, 01 Mar 2012 12:00:00 GMT"
</FilesMatch>