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Message-ID: <403CD372.7030609@apache.org>
Date: Wed, 25 Feb 2004 17:55:14 +0100
From: Henri Gomez <hgomez@apache.org>
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To: dev@httpd.apache.org
Subject: Re: Apache 2 module hook priorities, was: Help required on Apache
 from scratch...
References: <D17600FAE4FED711A1BD204C4F4F502008527A@MAILSERVER>
 <403CBE8B.20003@wstoddard.com> <403CC1F0.4030500@apache.org>
 <20040225162842.GD3295@gkar.earthdome.org>
In-Reply-To: <20040225162842.GD3295@gkar.earthdome.org>
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Glenn Nielsen wrote:

> On Wed, Feb 25, 2004 at 04:40:32PM +0100, Henri Gomez wrote:
> 
>>Bill Stoddard wrote:
>>
>>
>>>Benedict DSilva wrote:
>>>
>>>
>>>>Hi all,
>>>>Just wanted to know about how does the Apache HTTP Server start, and 
>>>>all that it does with the modules (Initialization, Configuration etc).
>>>
>>>
>>>Explaining how Apache HTTPD works to the degree of detail you are 
>>>looking for is a rather tall request to answer in an email. My 
>>>suggestion is to pick up a copy of Ryan Bloom's Complete Reference to 
>>>Apache 2.0 then read the code.
>>
>>Did there is a book for modules writers ?
>>
>>I'm working on jk2 connector (mod_jk2) and looking for some
>>nasty problem (mostly conflict between jk2 and others modules).
>>
>>Help welcomed ...
> 
> 
> Henri,
> 
> Getting the priority set correctly for hooks in JK2 is sticky.
> You might take a look at what I did setting hook priority in
> mod_jk 1.2 so that it would work correctly with mod_dir. My
> cvs commit messages might be helpful from 
> jakarta-tomcat-connectors/jk/native/apache-2.0/mod_jk.c .
> 
> Here is the page the docs how hook priority works:
> 
> http://httpd.apache.org/docs-2.0/developer/hooks.html
> 
> It all comes down to carefully reviewing the hook priority of other
> modules and how those modules interact with JK2. Then setting the
> hook priorities in JK2.

Well I read jk 1.2.x and 2.0.x and see no differences :

jk :

static void jk_register_hooks(apr_pool_t *p)
{
     ap_hook_handler(jk_handler,NULL,NULL,APR_HOOK_MIDDLE);
     ap_hook_post_config(jk_post_config,NULL,NULL,APR_HOOK_MIDDLE);
     ap_hook_child_init(jk_child_init,NULL,NULL,APR_HOOK_MIDDLE);
     ap_hook_translate_name(jk_translate,NULL,NULL,APR_HOOK_MIDDLE);
#if (MODULE_MAGIC_NUMBER_MAJOR > 20010808)
     ap_hook_map_to_storage(jk_map_to_storage,NULL,NULL,APR_HOOK_MIDDLE);
#endif
}


jk2 :

static void jk2_register_hooks(apr_pool_t *p)
{
     ap_hook_handler(jk2_handler, NULL, NULL, APR_HOOK_MIDDLE);
     ap_hook_post_config(jk2_post_config,NULL,NULL,APR_HOOK_MIDDLE);
     /* Force the mpm to run before us and set the scoreboard image */
     ap_hook_child_init(jk2_child_init,NULL,NULL,APR_HOOK_LAST);
     ap_hook_translate_name(jk2_translate,NULL,NULL,APR_HOOK_FIRST); /* 
use APR_HOOK_MIDDLE instead ? */
     ap_hook_map_to_storage(jk2_map_to_storage, NULL, NULL, 
APR_HOOK_MIDDLE);
}


The registering is very similar to me ...

I see in CVS that sometime in the past there was in jk :

static void jk_register_hooks(apr_pool_t *p)
  {  {
      ap_hook_handler(jk_handler, NULL, NULL, APR_HOOK_MIDDLE);      /* 
Make sure mod_alias runs before mod_jk to make sure that
           Alias's are mapped before mod_jk tries to process the request */
        static const char * const aszPre[] = { "mod_alias.c", NULL };

        /* Make sure mod_dir runs after mod_jk so that a
           DirectoryIndex index.jsp works */
        static const char * const aszPost[] = { "mod_dir.c", NULL };

        ap_hook_handler(jk_handler,aszPre,aszPost,APR_HOOK_MIDDLE);
      ap_hook_post_config(jk_post_config,NULL,NULL,APR_HOOK_MIDDLE); 
   ap_hook_post_config(jk_post_config,NULL,NULL,APR_HOOK_MIDDLE);
      ap_hook_child_init(jk_child_init,NULL,NULL,APR_HOOK_MIDDLE); 
ap_hook_child_init(jk_child_init,NULL,NULL,APR_HOOK_MIDDLE);
      ap_hook_translate_name(jk_translate,NULL,NULL,APR_HOOK_FIRST); 
   ap_hook_translate_name(jk_translate,aszPre,aszPost,APR_HOOK_MIDDLE);
  #if (MODULE_MAGIC_NUMBER_MAJOR > 20010808)  #if 
(MODULE_MAGIC_NUMBER_MAJOR > 20010808)
      ap_hook_map_to_storage(jk_map_to_storage, NULL, NULL, 
APR_HOOK_MIDDLE); 
ap_hook_map_to_storage(jk_map_to_storage,aszPre,aszPost,APR_HOOK_MIDDLE);
  #endif  #endif
  }  }


Need advices here ...