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Дата изменения: Mon Jan 21 19:44:30 2013 Дата индексирования: Fri Feb 28 07:25:16 2014 Кодировка: Поисковые слова: planetary nebula |
Apache HTTP Server Version 2.2
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.
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.
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
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 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 }; ap_hook_post_config(mmap_post_config,NULL,NULL,HOOK_MIDDLE); ap_hook_translate_name(mmap_static_xlat,aszPre,NULL,HOOK_LAST); };
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?
ap_hook_phase_name(function_name,
predecessors, successors, position);
There are 3 hook positions defined...
HOOK_FIRST
HOOK_MIDDLE
HOOK_LAST
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
.
There are now a lot fewer stages to worry about when creating your module definition. The old defintion looked like
module MODULE_VAR_EXPORT module_name_module = { STANDARD_MODULE_STUFF, /* 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 = { STANDARD20_MODULE_STUFF, /* 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 far...
ap_hook_post_config
_init
routines get
registeredap_hook_http_method
ap_hook_open_logs
ap_hook_auth_checker
ap_hook_access_checker
ap_hook_check_user_id
ap_hook_default_port
ap_hook_pre_connection
ap_hook_process_connection
ap_hook_child_init
ap_hook_create_request
ap_hook_fixups
ap_hook_handler
ap_hook_header_parser
post_read_request
for thisap_hook_insert_filter
ap_hook_log_transaction
ap_hook_optional_fn_retrieve
ap_hook_post_read_request
ap_hook_quick_handler
ap_hook_translate_name
ap_hook_type_checker