Antwort: [Mod_gzip] mod_zip and apache version

[Josep L. Guallar-Esteve]

On Tuesday 14 January 2003 05:27 am, Michael.Schroepl@telekurs.de wrote:
> Hi Josep,

Hi Michael.

> > 1.-  Which version of mod_gzip should I use for my system?

> Of course I suggest using the most recent one suitable
> for your Apache server.
> For Apache 1.3.x, this is mod_gzip 1.3.26.1a at the moment.

OK. Thanks.

> > > Are mod_gzip versions related in anyway with apache versions?

> Apache 1.3 and Apache 2.0 are very different products,
> so mod_gzip has to be written to fit the architecture
> of the Apache product.
> But then, the Apache 1.3 architecture hasn't changed for
> a long time, so you would be able to use any mod_gzip
> version from about 1.3.14. on with any Apache version
> from about 1.3.<singledigit> on - mod_gzip relies on some
> Apache regular expression handling that has been intro-
> duced in some early Apache 1.3 version, thus it would
> not work with Apache 1.2. (Not that I would suggest
> using such an olde Apache anyway ... ;-)

You answered my question. But my "real" question should have been:

Do you need mod_gzip-1.3.12 for apache-1.3.12 and so on? Are mod_gzip version 
numbers related in any way to apache version numbers?

By your answer, I understand that they are not related. 

> > 2.- Where can I find a fine manual so I can RTFM?

> The document that I would consider to be closest to a
> "manual" is on my website. It is part of the download
> package of mod_gzip 1.3.26.1a.

I'll download and check it out.

> If you have any questions not covered there, feel free
> to ask (and help me improve the documentation by your
> questions).

Sure. Thanks for the offer   :)

> Actually, your questions already made me start adding
> some of the corresponding information to these pages.

I'm helping! That's a first :P

> > 3.- Does anyone has mod_gzip used in production servers?
> > I'd like to know what "gotchas" have you found on produc-
> > tion environments.

> Sure. I am using it for about a year now.

Great!

> Any known bugs should be documented at the project's
> bug list:
>    http://sourceforge.net/tracker/?group_id=54975&atid=475503

Excellent.

> > (mail, http or similar).

> I don't understand what you mean with "mail" here.
> mod_gzip is an Apache module, and is used for HTTP
> traffic only.

OK. I should have used "webmail" instead. My fault.

> The HTTP protocol (RFC2616) supports "encoding" the
> content, which _may_ include applying a compression.
> I am not familiar with the mail protocols and whether
> they allow for any compression.

You are correct. "mail" was "web-base email".

> > I would like to use with our main webmail (https-squirrelmail)
> > server.

> It was a good idea that you mentioned "HTTPS" because
> this alone will pose a problem, due to the architecture
> of Apache 1.3 and the way mod_ssl operates.
> I suggest you to read the "mod_gzip and SSL mini howto"
>      http://lists.over.net/pipermail/mod_gzip/2002-February/005911.html

Mmmm. As I only use httpS I must read this. Thank you for raising the flag.

> (and today I finally managed to remember putting this
>  one on the link list of the mod_gzip docs, sigh ...
>  maybe I should even make it part of the documentation.)

It would be a nice addition for sure.

> PHP seems to be a tricky issue as well, just because
> there are so many ways you can use PHP in combination
> with an Apache server.
> You will have to find out which one applies to your con-
> figuration, and then tell mod_gzip exactly what to do.

OK. Although Squirrelmail team happily points to mod_zip to work with their 
product, a PHP application.

See:

http://www.squirrelmail.org/wiki/en_US/DecreasingBandwidth

> And then, there have been reports about problems using
> mod_gzip with some web servers that claim to be Apaches
> but have been modified internally by anyone.

Mine are true apaches.

> I never heard about your "Squirrelmail" package - so I
> cannot tell you whether you will experience any specific
> problems there. But from the SourceForge project page,
> this looks to be just a PHP application and no modifi-
> cation of Apache itself.

http://www.squirrelmail.org/

> > 4.- Any extra advice from mod_gzip users?

> - Be aware of what you want to get. Simply compressing
>   each and every HTTP output isn't a cure for everything.

Although it might solve some of the trouble.

> - Use file formats that are free of redundancies (optimi-
>   zed GIF/PNG images) so that you won't have to compress
>   their content again and again.

php-generated files, text only.

> - Do other optimizations as well - like running your
>   Web content through some stripper that would remove
>   unnecessary white space and the like.

Mmmm. Can you provide some pointers about this?

> - Think about keeping static pages in precompressed form
>   cached on your Apache server; mod_gzip 1.3.26.1a will
>   help you a lot with this, and this may save a lot of
>   CPU power.

Excellent. CPU power is no problem (so far).

> - Be aware of UserAgents having problems with compressed
>   content - but don't let that intimidate you using it.

Mozilla is the corporate-supported browser. Mozilla is listed as supported 
browser. If a users uses a non-supported browser, they are on their own. They 
can always go back to Mozilla.

> - Encourage the HTTP clients to not request the same con-
>   tent again and again, by sending them expiration dates
>   via HTTP headers ("Expires:", "Cache-Control:").

I believe that this doesn't apply. The usage of this webserver is webmail.

> - As a front end for your Apache server, use a good proxy
>   cache that is able to hold variants of negotiated
>   (compressed/uncompressed) content, like Squid 2.5.

Working with SSL conenctions and email, makes me think that a proxy won't 
really help. Correct me if I'm wrong.

> Regards, Michael

Tahnk you again.


Regards,
Josep
-- 
Josep L. Guallar-Esteve		Eastern Radiologists, Inc.
Systems and Network Administration  http://www.easternrad.com