Semi-complicated question: modifying the content of a request before passing to CGI?

[Seldo <ne...@seldo.com>]

Okay, so here's what I need to do:
  1. Receive a request to a given URI, X
  
  2. Based on that URI, change certain values with the request
     (e.g. change the names or values of variables posted by the user,
     modify the "x-www-form-urlencoded" data, whatever...)
     
  3. Translate the URI to a new URI (one of a number of CGI programs)
  
  4. Execute that CGI (such that the CGI runs in an environment with
     variables and posted data modified as per step 2 )

I'm running mod_perl 2.0 with Apache 2.0.x, and the documentation of
these sorts of features:

http://perl.apache.org/docs/2.0/api/Apache/RequestUtil.html

...is sort of incomplete. Whoopsie. My fault for being all
bleeding-edge, right? Here's what I've got so far:

  1. Can do. I can write a PerlTransHandler that catches the URI

  2. Don't know how to do. The 1.0 documentation mentions the
  header_in() method which can apparently set headers in the request
  as well as get them. I can't find this method in the 2.0
  documentation, does it or an equivalent exist? And is there anything
  similar for the PUT/POST type data?
  
  3. Can do. This bit is no problem.

  4. Don't know how to do. How do you tell the server to execute a
  file using CGI protocol? Is this even possible?


The above method, assuming it's possible to do the two things I asked
about, will work fine. If it doesn't work, then I'll be forced to make
my PerlTransHandler re-implement CGI, which isn't *that* hard but
sounds like a fairly stupid idea when the server does it already. But
even in the case, I need to know how to set "environment variables"
for CGI on a per-execution basis.

Any help greatly appreciated, this project is now due in a week and
I'm beginning to feel great big stormclouds of doom closing in :-)

Seldo.

P.S. I only recently noticed that Stas, who helped me out with my last
question, is listed as the author/maintainer of the 2.0 documentation.
Cool! :-)
____________________________________________
  Seldo Voss: www.seldo.com
  ICQ #1172379 or me@seldo.com
--------------------------------------------
Bart's Blackboard: "I will not eat things for money."

Re: Semi-complicated question: modifying the content of a request before passing to CGI?

[Stas Bekman <st...@stason.org>]

Seldo wrote:
> Okay, so here's what I need to do:
>   1. Receive a request to a given URI, X
>   
>   2. Based on that URI, change certain values with the request
>      (e.g. change the names or values of variables posted by the user,
>      modify the "x-www-form-urlencoded" data, whatever...)
>      
>   3. Translate the URI to a new URI (one of a number of CGI programs)
>   
>   4. Execute that CGI (such that the CGI runs in an environment with
>      variables and posted data modified as per step 2 )
> 
> I'm running mod_perl 2.0 with Apache 2.0.x, and the documentation of
> these sorts of features:
> 
> http://perl.apache.org/docs/2.0/api/Apache/RequestUtil.html
> 
> ...is sort of incomplete. Whoopsie. 

We have very few hands, so coding is of a higher priority. Most of the API 
docs from 1.0 apply to 2.0. Almost all differrences are documented here:
http://perl.apache.org/docs/2.0/user/compat/compat.html
If something is missing, please post patches.

Help with 2.0 docs is very welcome.

> My fault for being all
> bleeding-edge, right? Here's what I've got so far:
> 
>   1. Can do. I can write a PerlTransHandler that catches the URI
> 
>   2. Don't know how to do. The 1.0 documentation mentions the
>   header_in() method which can apparently set headers in the request
>   as well as get them. I can't find this method in the 2.0
>   documentation, does it or an equivalent exist? 
http://perl.apache.org/docs/2.0/user/compat/compat.html#C__r_E_gt_header_in_

> And is there anything
>   similar for the PUT/POST type data?

what do you mean? check the above URL.

>   3. Can do. This bit is no problem.
> 
>   4. Don't know how to do. How do you tell the server to execute a
>   file using CGI protocol? Is this even possible?

You don't need to do anything. Just configure your mod_cgi as usual, and once 
you've changed $r->filename to point to the location of cgi, Apache will take 
care of it. (I assume that you want the cgis to be run by mod_cgi, not mod_perl)

> The above method, assuming it's possible to do the two things I asked
> about, will work fine. If it doesn't work, then I'll be forced to make
> my PerlTransHandler re-implement CGI, which isn't *that* hard but
> sounds like a fairly stupid idea when the server does it already. But
> even in the case, I need to know how to set "environment variables"
> for CGI on a per-execution basis.
> 
> Any help greatly appreciated, this project is now due in a week and
> I'm beginning to feel great big stormclouds of doom closing in :-)

Your task is pretty trivial, so you should be fine.

> Seldo.
> 
> P.S. I only recently noticed that Stas, who helped me out with my last
> question, is listed as the author/maintainer of the 2.0 documentation.
> Cool! :-)

Hopefully this will change asap and other people will take over varous documents.

__________________________________________________________________
Stas Bekman            JAm_pH ------> Just Another mod_perl Hacker
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