Convince Firefox to send an If-Modified-Since header over HTTPS

Question

How can I convince Firefox (3.0.1, if it matters) to send an If-Modified-Since header in an HTTPS request? It sends the header if the request uses plain HTTP and my server duti

Answer 1

HTTPS requests are not cached so sending an If-Modified-Since doesn't make any sense. The not caching is a security precaution.

The not caching on disk is a security pre-caution, but it seems it indeed affects the If-Modified-Since behavior (glancing over the code).

Try setting the Firefox preference (in about:config) browser.cache.disk_cache_ssl to true. If that helps, try sending Cache-Control: public header in your response.

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UPDATE: Firefox behavior was changed for Gecko 2.0 (Firefox 4) -- HTTPS content is now cached.