296901 - xmlhttprequest sends no-cache request header

Status: RESOLVED DUPLICATE of bug 268844

(Firefox :: General, defect)

Description

[ppmm]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.8) Gecko/20050511 Firefox/1.0.4 (ax)
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.8) Gecko/20050511 Firefox/1.0.4 (ax)

I don't see an obvious reason that xmlhttprequest wants to send a Cache-Control:
no-cache header (as well as Pragma: no-cache header). I don't find an obvious
way of disabling this. This makes it impossible to use intermediate HTTP cache
for more efficient web communication, unless we violate HTTP in the cache server
(like configuring reload-into-ims for refresh_pattern in squid). If I do want to
request fresh content from the main server, I could choose to send this header
manually, but now I don't have a choice of not sending it, which doesn't make
too much sense to me. And finally, IE doesn't send no-cache header.

Reproducible: Always

Steps to Reproduce:
send request using xmlhttprequest
Actual Results:  
sample request headers:

GET /ajax.php?id=3 HTTP/1.1
Host: 192.168.0.11:8080
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.8)
Gecko/20050511 Firefox/1.0.4 (ax)
Accept:
text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5
Accept-Language: en-us,en;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 300
Connection: keep-alive
Pragma: no-cache
Cache-Control: no-cache


Expected Results:  
do not send the following two headers:

Pragma: no-cache
Cache-Control: no-cache

Comment 1

[Erik Arvidsson]

We've seen a similar behavior.

XMLHttpRequest does not send the If-Modified-Since header prevent the caching of
the requests even when using GET. If the same file is accessed directly using
Mozilla the caching works great.

Comment 2

[Christian :Biesinger (don't email me, ping me on IRC)]

*** This bug has been marked as a duplicate of 268844 ***