Planning to change the content of the object.

>>>>> "George_Ma" == <maer727@sohu.com> writes:

    George_Ma> Hi, pals! I am trying to change the content of some
    George_Ma> cached object, for example, change one gif to another
    George_Ma> gif.

You definitely should consider using the Internet Content Adaptation
Protocol. See www.i-cap.org for definition and tutorial on ICAP

There is an existing ICAP enhanced Squid. See
http://sourceforge.net/projects/icap-server/

I would recommand against patching directly Squid for content
adaptation. Definitely use ICAP for that!

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Basile STARYNKEVITCH         http://starynkevitch.net/Basile/ 
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