Converting Modules from Apache 1.3 to Apache 2.0 - Apache HTTP Server Version 2.4

Modules | Directives | FAQ | Glossary | Sitemap
Apache HTTP Server Version 2.4

Apache > HTTP Server > Documentation > Version 2.4 > Developer DocumentationConverting Modules from Apache 1.3 to Apache 2.0

Available Languages:  en  |

    This is a first attempt at writing the lessons I learned
    when trying to convert the mod_mmap_static module to Apache
    2.0. It's by no means definitive and probably won't even be
    correct in some ways, but it's a start.

 The easier changes ...
 The messier changes...
See alsoComments

The easier changes ...

    Cleanup Routines
      These now need to be of type apr_status_t and return a
      value of that type. Normally the return value will be
      APR_SUCCESS unless there is some need to signal an error in
      the cleanup. Be aware that even though you signal an error not all code
      yet checks and acts upon the error.

    Initialisation Routines
      These should now be renamed to better signify where they sit
      in the overall process. So the name gets a small change from
      mmap_init to mmap_post_config. The arguments
      passed have undergone a radical change and now look like

        apr_pool_t *p
        apr_pool_t *plog
        apr_pool_t *ptemp
        server_rec *s

    Data Types
      A lot of the data types have been moved into the APR. This means that some have had
      a name change, such as the one shown above. The following is a brief
      list of some of the changes that you are likely to have to make.

        pool becomes apr_pool_t
        table becomes apr_table_t

The messier changes...

    Register Hooks
      The new architecture uses a series of hooks to provide for
      calling your functions. These you'll need to add to your module
      by way of a new function, static void register_hooks(void).
      The function is really reasonably straightforward once you
      understand what needs to be done. Each function that needs
      calling at some stage in the processing of a request needs to
      be registered, handlers do not. There are a number of phases
      where functions can be added, and for each you can specify with
      a high degree of control the relative order that the function
      will be called in.

      This is the code that was added to mod_mmap_static:
      static void register_hooks(void)
    static const char * const aszPre[]={ "http_core.c",NULL };

      This registers 2 functions that need to be called, one in
      the post_config stage (virtually every module will need this
      one) and one for the translate_name phase. note that while
      there are different function names the format of each is
      identical. So what is the format?

        predecessors, successors, position);

      There are 3 hook positions defined...


      To define the position you use the position and then modify
      it with the predecessors and successors. Each of the modifiers
      can be a list of functions that should be called, either before
      the function is run (predecessors) or after the function has
      run (successors).

      In the mod_mmap_static case I didn't care about the
      post_config stage, but the mmap_static_xlat
      must be called after the core module had done its name
      translation, hence the use of the aszPre to define a modifier to the
      position HOOK_LAST.

    Module Definition
      There are now a lot fewer stages to worry about when
      creating your module definition. The old definition looked

      module MODULE_VAR_EXPORT module_name_module =
    /* initializer */
    /* dir config creater */
    /* dir merger --- default is to override */
    /* server config */
    /* merge server config */
    /* command handlers */
    /* handlers */
    /* filename translation */
    /* check_user_id */
    /* check auth */
    /* check access */
    /* type_checker */
    /* fixups */
    /* logger */
    /* header parser */
    /* child_init */
    /* child_exit */
    /* post read-request */

      The new structure is a great deal simpler...
      module MODULE_VAR_EXPORT module_name_module =
    /* create per-directory config structures */
    /* merge per-directory config structures  */
    /* create per-server config structures    */
    /* merge per-server config structures     */
    /* command handlers */
    /* handlers */
    /* register hooks */

      Some of these read directly across, some don't. I'll try to
      summarise what should be done below.

      The stages that read directly across :

        /* dir config creater */
        /* create per-directory config structures */

        /* server config */
        /* create per-server config structures */

        /* dir merger */
        /* merge per-directory config structures */

        /* merge server config */
        /* merge per-server config structures */

        /* command table */
        /* command apr_table_t */

        /* handlers */
        /* handlers */

      The remainder of the old functions should be registered as
      hooks. There are the following hook stages defined so

        do any setup required prior to processing configuration

        review configuration directive interdependencies

        executes only with -t option

        open any specified logs

        this is where the old _init routines get

        retrieve the http method from a request. (legacy)

        check if the resource requires authorization

        check for module-specific restrictions

        check the user-id and password

        retrieve the default port for the server

        do any setup required just before processing, but after

        run the correct protocol

        call as soon as the child is started


        last chance to modify things before generating content

        generate the content

        lets modules look at the headers, not used by most modules, because
        they use post_read_request for this

        to insert filters into the filter chain

        log information about the request

        retrieve any functions registered as optional

        called after reading the request, before any other phase

        called before any request processing, used by cache modules.

        translate the URI into a filename

        determine and/or set the doc type

Available Languages:  en  |
CommentsNotice:This is not a Q&A section. Comments placed here should be pointed towards suggestions on improving the documentation or server, and may be removed again by our moderators if they are either implemented or considered invalid/off-topic. Questions on how to manage the Apache HTTP Server should be directed at either our IRC channel, #httpd, on Freenode, or sent to our mailing lists.

Copyright 2017 The Apache Software Foundation.Licensed under the Apache License, Version 2.0.
Modules | Directives | FAQ | Glossary | Sitemap
page_1 | page_2 | page_3 | page_4 | page_5 | сальса.рф
Warning: simplexml_load_file(): sites/ parser error : Extra content at the end of the document in /home/artem/pool/index.php on line 77

Warning: simplexml_load_file(): root> in /home/artem/pool/index.php on line 77

Warning: simplexml_load_file(): ^ in /home/artem/pool/index.php on line 77

Fatal error: Call to a member function xpath() on a non-object in /home/artem/pool/index.php on line 82