Apache Request Processing

Collaboration diagram for Apache Request Processing:

Modules
	Access Control for Sub-Requests and

Macros
#define	AP_SUBREQ_NO_ARGS   0
#define	AP_SUBREQ_MERGE_ARGS   1
#define	MERGE_ALLOW   0
#define	REPLACE_ALLOW   1
#define	AP_BUCKET_IS_EOR(e)   ((e)->type == &ap_bucket_type_eor)

Functions
int	ap_process_request_internal (request_rec *r)
request_rec *	ap_sub_req_lookup_uri (const char *new_uri, const request_rec *r, ap_filter_t *next_filter)
request_rec *	ap_sub_req_lookup_file (const char *new_file, const request_rec *r, ap_filter_t *next_filter)
request_rec *	ap_sub_req_lookup_dirent (const apr_finfo_t *finfo, const request_rec *r, int subtype, ap_filter_t *next_filter)
request_rec *	ap_sub_req_method_uri (const char *method, const char *new_uri, const request_rec *r, ap_filter_t *next_filter)
apr_status_t	ap_sub_req_output_filter (ap_filter_t *f, apr_bucket_brigade *bb)
int	ap_run_sub_req (request_rec *r)
void	ap_destroy_sub_req (request_rec *r)
void	ap_internal_redirect (const char *new_uri, request_rec *r)
void	ap_internal_redirect_handler (const char *new_uri, request_rec *r)
void	ap_internal_fast_redirect (request_rec *sub_req, request_rec *r)
int	ap_some_auth_required (request_rec *r)
apr_array_header_t *	authn_ap_list_provider_names (apr_pool_t *ptemp)
apr_array_header_t *	authz_ap_list_provider_names (apr_pool_t *ptemp)
int	ap_is_initial_req (request_rec *r)
void	ap_update_mtime (request_rec *r, apr_time_t dependency_mtime)
void	ap_allow_methods (request_rec *r, int reset,...) AP_FN_ATTR_SENTINEL
void	ap_allow_standard_methods (request_rec *r, int reset,...)
void	ap_process_request (request_rec *r)
void	ap_process_request_after_handler (request_rec *r)
void	ap_process_async_request (request_rec *r)
void	ap_die (int type, request_rec *r)
apr_status_t	ap_check_pipeline (conn_rec *c, apr_bucket_brigade *bb, unsigned int max_blank_lines)
void	ap_hook_check_access (ap_HOOK_access_checker_t *pf, const char *const *aszPre, const char *const *aszSucc, int nOrder, int type)
void	ap_hook_check_access_ex (ap_HOOK_access_checker_ex_t *pf, const char *const *aszPre, const char *const *aszSucc, int nOrder, int type)
void	ap_hook_check_autht (ap_HOOK_token_checker_t *pf, const char *const *aszPre, const char *const *aszSucc, int nOrder, int type)
void	ap_hook_check_authn (ap_HOOK_check_user_id_t *pf, const char *const *aszPre, const char *const *aszSucc, int nOrder, int type)
void	ap_hook_check_authz (ap_HOOK_auth_checker_t *pf, const char *const *aszPre, const char *const *aszSucc, int nOrder, int type)
int	ap_location_walk (request_rec *r)
int	ap_directory_walk (request_rec *r)
int	ap_file_walk (request_rec *r)
int	ap_if_walk (request_rec *r)
apr_bucket *	ap_bucket_eor_make (apr_bucket *b, request_rec *r)
apr_bucket *	ap_bucket_eor_create (apr_bucket_alloc_t *list, request_rec *r)
request_rec *	ap_bucket_eor_request (apr_bucket *b)
int	ap_some_authn_required (request_rec *r)

Variables
AP_DECLARE_DATA const apr_bucket_type_t	ap_bucket_type_eor

Detailed Description

Macro Definition Documentation

AP_BUCKET_IS_EOR

#define AP_BUCKET_IS_EOR

(

e

)

((e)->type == &ap_bucket_type_eor)

Determine if a bucket is an End Of REQUEST (EOR) bucket

Parameters

e	The bucket to inspect

Returns

true or false

AP_SUBREQ_MERGE_ARGS

#define AP_SUBREQ_MERGE_ARGS   1

AP_SUBREQ_NO_ARGS

#define AP_SUBREQ_NO_ARGS   0

MERGE_ALLOW

#define MERGE_ALLOW   0

REPLACE_ALLOW

#define REPLACE_ALLOW   1

Function Documentation

ap_allow_methods()

void ap_allow_methods	(	request_rec *	r,
		int	reset,
			...
	)

Add one or more methods to the list permitted to access the resource. Usually executed by the content handler before the response header is sent, but sometimes invoked at an earlier phase if a module knows it can set the list authoritatively. Note that the methods are ADDED to any already permitted unless the reset flag is non-zero. The list is used to generate the Allow response header field when it is needed.

Parameters

r	The pointer to the request identifying the resource.
reset	Boolean flag indicating whether this list should completely replace any current settings.
...	A NULL-terminated list of strings, each identifying a method name to add.

Returns

None.

ap_allow_standard_methods()

void ap_allow_standard_methods	(	request_rec *	r,
		int	reset,
			...
	)

Add one or more methods to the list permitted to access the resource. Usually executed by the content handler before the response header is sent, but sometimes invoked at an earlier phase if a module knows it can set the list authoritatively. Note that the methods are ADDED to any already permitted unless the reset flag is non-zero. The list is used to generate the Allow response header field when it is needed.

Parameters

r	The pointer to the request identifying the resource.
reset	Boolean flag indicating whether this list should completely replace any current settings.
...	A list of method identifiers, from the "M_" series defined in httpd.h, terminated with a value of -1 (e.g., "M_GET, M_POST, M_OPTIONS, -1")

Returns

None.

ap_bucket_eor_create()

apr_bucket* ap_bucket_eor_create	(	apr_bucket_alloc_t *	list,
		request_rec *	r
	)

Create a bucket referring to an End Of REQUEST (EOR). This bucket holds a pointer to the request_rec, so that the request can be destroyed right after all of the output has been sent to the client.

Parameters

list	The freelist from which this bucket should be allocated
r	The request to destroy when this bucket is destroyed

Returns

The new bucket, or NULL if allocation failed

ap_bucket_eor_make()

apr_bucket* ap_bucket_eor_make	(	apr_bucket *	b,
		request_rec *	r
	)

Make the bucket passed in an End Of REQUEST (EOR) bucket

Parameters

b	The bucket to make into an EOR bucket
r	The request to destroy when this bucket is destroyed

Returns

The new bucket, or NULL if allocation failed

ap_bucket_eor_request()

request_rec* ap_bucket_eor_request

(

apr_bucket *

b

)

Get the request bound to an End Of Request (EOR) bucket.

Parameters

b	The EOR bucket

Returns

Its associated request

ap_check_pipeline()

apr_status_t ap_check_pipeline	(	conn_rec *	c,
		apr_bucket_brigade *	bb,
		unsigned int	max_blank_lines
	)

Check whether a connection is still established and has data available, optionally consuming blank lines ([CR]LF).

Parameters

c	The current connection
bb	The brigade to filter
max_blank_lines	Max number of blank lines to consume, or zero to consider them as data (single read).

Returns

APR_SUCCESS: connection established with data available, APR_EAGAIN: connection established and empty, APR_NOTFOUND: too much blank lines, APR_E*: connection/general error.

ap_destroy_sub_req()

void ap_destroy_sub_req

(

request_rec *

r

)

Free the memory associated with a subrequest

Parameters

r	The subrequest to finish

ap_die()

void ap_die	(	int	type,
		request_rec *	r
	)

Kill the current request

Parameters

type	Why the request is dying
r	The current request

ap_directory_walk()

int ap_directory_walk

(

request_rec *

r

)

ap_file_walk()

int ap_file_walk

(

request_rec *

r

)

ap_hook_check_access()

void ap_hook_check_access	(	ap_HOOK_access_checker_t *	pf,
		const char *const *	aszPre,
		const char *const *	aszSucc,
		int	nOrder,
		int	type
	)

Register a hook function that will apply additional access control to the current request.

Parameters

pf	An access_checker hook function
aszPre	A NULL-terminated array of strings that name modules whose hooks should precede this one
aszSucc	A NULL-terminated array of strings that name modules whose hooks should succeed this one
nOrder	An integer determining order before honouring aszPre and aszSucc (for example, HOOK_MIDDLE)
type	Internal request processing mode, either AP_AUTH_INTERNAL_PER_URI or AP_AUTH_INTERNAL_PER_CONF

ap_hook_check_access_ex()

void ap_hook_check_access_ex	(	ap_HOOK_access_checker_ex_t *	pf,
		const char *const *	aszPre,
		const char *const *	aszSucc,
		int	nOrder,
		int	type
	)

Register a hook function that will apply additional access control and/or bypass authentication for the current request.

Parameters

pf	An access_checker_ex hook function
aszPre	A NULL-terminated array of strings that name modules whose hooks should precede this one
aszSucc	A NULL-terminated array of strings that name modules whose hooks should succeed this one
nOrder	An integer determining order before honouring aszPre and aszSucc (for example, HOOK_MIDDLE)
type	Internal request processing mode, either AP_AUTH_INTERNAL_PER_URI or AP_AUTH_INTERNAL_PER_CONF

ap_hook_check_authn()

void ap_hook_check_authn	(	ap_HOOK_check_user_id_t *	pf,
		const char *const *	aszPre,
		const char *const *	aszSucc,
		int	nOrder,
		int	type
	)

Register a hook function that will analyze the request headers, authenticate the user, and set the user information in the request record.

Parameters

pf	A check_user_id hook function
aszPre	A NULL-terminated array of strings that name modules whose hooks should precede this one
aszSucc	A NULL-terminated array of strings that name modules whose hooks should succeed this one
nOrder	An integer determining order before honouring aszPre and aszSucc (for example, HOOK_MIDDLE)
type	Internal request processing mode, either AP_AUTH_INTERNAL_PER_URI or AP_AUTH_INTERNAL_PER_CONF

ap_hook_check_autht()

void ap_hook_check_autht	(	ap_HOOK_token_checker_t *	pf,
		const char *const *	aszPre,
		const char *const *	aszSucc,
		int	nOrder,
		int	type
	)

Register a hook function that will analyze the request headers, extract any tokens, and apply and metadata contained in the tokens or keyed against the tokens to the request record.

Parameters

pf	A token_checker hook function
aszPre	A NULL-terminated array of strings that name modules whose hooks should precede this one
aszSucc	A NULL-terminated array of strings that name modules whose hooks should succeed this one
nOrder	An integer determining order before honouring aszPre and aszSucc (for example, HOOK_MIDDLE)
type	Internal request processing mode, either AP_AUTH_INTERNAL_PER_URI or AP_AUTH_INTERNAL_PER_CONF

ap_hook_check_authz()

void ap_hook_check_authz	(	ap_HOOK_auth_checker_t *	pf,
		const char *const *	aszPre,
		const char *const *	aszSucc,
		int	nOrder,
		int	type
	)

Register a hook function that determine if the resource being requested is available for the currently authenticated user.

Parameters

pf	An auth_checker hook function
aszPre	A NULL-terminated array of strings that name modules whose hooks should precede this one
aszSucc	A NULL-terminated array of strings that name modules whose hooks should succeed this one
nOrder	An integer determining order before honouring aszPre and aszSucc (for example, HOOK_MIDDLE)
type	Internal request processing mode, either AP_AUTH_INTERNAL_PER_URI or AP_AUTH_INTERNAL_PER_CONF

ap_if_walk()

int ap_if_walk

(

request_rec *

r

)

ap_internal_fast_redirect()

void ap_internal_fast_redirect	(	request_rec *	sub_req,
		request_rec *	r
	)

Redirect the current request to a sub_req, merging the pools

Parameters

sub_req	A subrequest created from this request
r	The current request

Note

the sub_req's pool will be merged into r's pool, be very careful not to destroy this subrequest, it will be destroyed with the main request!

ap_internal_redirect()

void ap_internal_redirect	(	const char *	new_uri,
		request_rec *	r
	)

Redirect the current request to some other uri

Parameters

new_uri	The URI to replace the current request with
r	The current request

ap_internal_redirect_handler()

void ap_internal_redirect_handler	(	const char *	new_uri,
		request_rec *	r
	)

This function is designed for things like actions or CGI scripts, when using AddHandler, and you want to preserve the content type across an internal redirect.

Parameters

new_uri	The URI to replace the current request with.
r	The current request

ap_is_initial_req()

int ap_is_initial_req

(

request_rec *

r

)

Determine if the current request is the main request or a subrequest

Parameters

r	The current request

Returns

1 if this is the main request, 0 otherwise

ap_location_walk()

int ap_location_walk

(

request_rec *

r

)

ap_process_async_request()

void ap_process_async_request

(

request_rec *

r

)

Process a top-level request from a client, allowing some or all of the response to remain buffered in the core output filter for later, asynchronous write completion

Parameters

r	The current request

ap_process_request()

void ap_process_request

(

request_rec *

r

)

Process a top-level request from a client, and synchronously write the response to the client

Parameters

r	The current request

ap_process_request_after_handler()

void ap_process_request_after_handler

(

request_rec *

r

)

ap_process_request_internal()

int ap_process_request_internal

(

request_rec *

r

)

An internal handler used by the ap_process_request, all subrequest mechanisms and the redirect mechanism.

Parameters

r	The request, subrequest or internal redirect to pre-process

Returns

The return code for the request

ap_run_sub_req()

int ap_run_sub_req

(

request_rec *

r

)

Run the handler for the subrequest

Parameters

r	The subrequest to run

Returns

The return code for the subrequest

ap_some_auth_required()

int ap_some_auth_required

(

request_rec *

r

)

Can be used within any handler to determine if any authentication is required for the current request

Parameters

r	The current request

Returns

1 if authentication is required, 0 otherwise

Bug:

Behavior changed in 2.4.x refactoring, API no longer usable

Deprecated:

See also

ap_some_authn_required()

ap_some_authn_required()

int ap_some_authn_required

(

request_rec *

r

)

Can be used within any handler to determine if any authentication is required for the current request. Note that if used with an access_checker hook, an access_checker_ex hook or an authz provider; the caller should take steps to avoid a loop since this function is implemented by calling these hooks.

Parameters

r	The current request

Returns

TRUE if authentication is required, FALSE otherwise

ap_sub_req_lookup_dirent()

request_rec* ap_sub_req_lookup_dirent	(	const apr_finfo_t *	finfo,
		const request_rec *	r,
		int	subtype,
		ap_filter_t *	next_filter
	)

Create a subrequest for the given apr_dir_read result. This subrequest can be inspected to find information about the requested file

Parameters

finfo	The apr_dir_read result to lookup
r	The current request
subtype	What type of subrequest to perform, one of; AP_SUBREQ_NO_ARGS ignore r->args and r->path_info AP_SUBREQ_MERGE_ARGS merge r->args and r->path_info
next_filter	The first filter the sub_request should use. If this is NULL, it defaults to the first filter for the main request

Returns

The new request record

Note

The apr_dir_read flags value APR_FINFO_MIN|APR_FINFO_NAME flag is the minimum recommended query if the results will be passed to apr_dir_read. The file info passed must include the name, and must have the same relative directory as the current request.

ap_sub_req_lookup_file()

request_rec* ap_sub_req_lookup_file	(	const char *	new_file,
		const request_rec *	r,
		ap_filter_t *	next_filter
	)

Create a subrequest for the given file. This subrequest can be inspected to find information about the requested file

Parameters

new_file	The file to lookup
r	The current request
next_filter	The first filter the sub_request should use. If this is NULL, it defaults to the first filter for the main request

Returns

The new request record

ap_sub_req_lookup_uri()

request_rec* ap_sub_req_lookup_uri	(	const char *	new_uri,
		const request_rec *	r,
		ap_filter_t *	next_filter
	)

Create a subrequest from the given URI. This subrequest can be inspected to find information about the requested URI

Parameters

new_uri	The URI to lookup
r	The current request
next_filter	The first filter the sub_request should use. If this is NULL, it defaults to the first filter for the main request

Returns

The new request record

ap_sub_req_method_uri()

request_rec* ap_sub_req_method_uri	(	const char *	method,
		const char *	new_uri,
		const request_rec *	r,
		ap_filter_t *	next_filter
	)

Create a subrequest for the given URI using a specific method. This subrequest can be inspected to find information about the requested URI

Parameters

method	The method to use in the new subrequest
new_uri	The URI to lookup
r	The current request
next_filter	The first filter the sub_request should use. If this is NULL, it defaults to the first filter for the main request

Returns

The new request record

ap_sub_req_output_filter()

apr_status_t ap_sub_req_output_filter	(	ap_filter_t *	f,
		apr_bucket_brigade *	bb
	)

An output filter to strip EOS buckets from sub-requests. This always has to be inserted at the end of a sub-requests filter stack.

Parameters

f	The current filter
bb	The brigade to filter

Returns

status code

ap_update_mtime()

void ap_update_mtime	(	request_rec *	r,
		apr_time_t	dependency_mtime
	)

Function to set the r->mtime field to the specified value if it's later than what's already there.

Parameters

r	The current request
dependency_mtime	Time to set the mtime to

authn_ap_list_provider_names()

apr_array_header_t* authn_ap_list_provider_names

(

apr_pool_t *

ptemp

)

authz_ap_list_provider_names()

apr_array_header_t* authz_ap_list_provider_names

(

apr_pool_t *

ptemp

)

Variable Documentation

ap_bucket_type_eor

AP_DECLARE_DATA const apr_bucket_type_t ap_bucket_type_eor

extern

End Of REQUEST (EOR) bucket