mod_headers.c revision 73e8b26287de5c06fa470d36162e103dbac9c7e5
/* ====================================================================
* The Apache Software License, Version 1.1
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*
* Portions of this software are based upon public domain software
* originally written at the National Center for Supercomputing Applications,
* University of Illinois, Urbana-Champaign.
*/
/*
* mod_headers.c: Add/append/remove HTTP response headers
* Written by Paul Sutton, paul@ukweb.com, 1 Oct 1996
*
* New directive, Header, can be used to add/replace/remove HTTP headers.
* Valid in both per-server and per-dir configurations.
*
* Syntax is:
*
* Header action header value
*
* Where action is one of:
* set - set this header, replacing any old value
* add - add this header, possible resulting in two or more
* headers with the same name
* append - append this text onto any existing header of this same
* unset - remove this header
*
* Where action is unset, the third argument (value) should not be given.
* The header name can include the colon, or not.
*
* The Header directive can only be used where allowed by the FileInfo
* override.
*
* When the request is processed, the header directives are processed in
* this order: firstly, the main server, then the virtual server handling
* this request (if any), then any <Directory> sections (working downwards
* from the root dir), then an <Location> sections (working down from
* shortest URL component), the any <File> sections. This order is
* important if any 'set' or 'unset' actions are used. For example,
* the following two directives have different effect if applied in
* the reverse order:
*
* Header append Author "John P. Doe"
* Header unset Author
*
* Examples:
*
* To set the "Author" header, use
* Header add Author "John P. Doe"
*
* To remove a header:
* Header unset Author
*
*/
#include "apr_strings.h"
#include "httpd.h"
#include "http_config.h"
#include "http_request.h"
#ifdef HAVE_STRINGS_H
#include <strings.h>
#endif
typedef enum {
hdr_add = 'a', /* add header (could mean multiple hdrs) */
hdr_set = 's', /* set (replace old value) */
hdr_append = 'm', /* append (merge into any old value) */
hdr_unset = 'u' /* unset header */
} hdr_actions;
typedef struct {
hdr_actions action;
char *header;
const char *value;
} header_entry;
/*
* headers_conf is our per-module configuration. This is used as both
* a per-dir and per-server config
*/
typedef struct {
apr_array_header_t *headers;
} headers_conf;
module AP_MODULE_DECLARE_DATA headers_module;
static void *create_headers_config(apr_pool_t *p, server_rec *s)
{
headers_conf *a =
(headers_conf *) apr_pcalloc(p, sizeof(headers_conf));
a->headers = apr_make_array(p, 2, sizeof(header_entry));
return a;
}
static void *create_headers_dir_config(apr_pool_t *p, char *d)
{
return (headers_conf *) create_headers_config(p, NULL);
}
static void *merge_headers_config(apr_pool_t *p, void *basev, void *overridesv)
{
headers_conf *a =
(headers_conf *) apr_pcalloc(p, sizeof(headers_conf));
headers_conf *base = (headers_conf *) basev, *overrides = (headers_conf *) overridesv;
a->headers = apr_append_arrays(p, base->headers, overrides->headers);
return a;
}
static const char *header_cmd(cmd_parms *cmd, void *indirconf,
const char *action, const char *inhdr, const char *value)
{
headers_conf *dirconf = indirconf;
char *hdr = apr_pstrdup(cmd->pool, inhdr);
header_entry *new;
server_rec *s = cmd->server;
headers_conf *serverconf =
(headers_conf *) ap_get_module_config(s->module_config, &headers_module);
char *colon;
if (cmd->path) {
new = (header_entry *) apr_push_array(dirconf->headers);
}
else {
new = (header_entry *) apr_push_array(serverconf->headers);
}
if (!strcasecmp(action, "set"))
new->action = hdr_set;
else if (!strcasecmp(action, "add"))
new->action = hdr_add;
else if (!strcasecmp(action, "append"))
new->action = hdr_append;
else if (!strcasecmp(action, "unset"))
new->action = hdr_unset;
else
return "first argument must be add, set, append or unset.";
if (new->action == hdr_unset) {
if (value)
return "Header unset takes two arguments";
}
else if (!value)
return "Header requires three arguments";
if ((colon = strchr(hdr, ':')))
*colon = '\0';
new->header = hdr;
new->value = value;
return NULL;
}
static const command_rec headers_cmds[] =
{
AP_INIT_TAKE23("Header", header_cmd, NULL, OR_FILEINFO,
"an action, header and value"),
{NULL}
};
static void do_headers_fixup(request_rec *r, apr_array_header_t *headers)
{
int i;
for (i = 0; i < headers->nelts; ++i) {
header_entry *hdr = &((header_entry *) (headers->elts))[i];
switch (hdr->action) {
case hdr_add:
apr_table_addn(r->headers_out, hdr->header, hdr->value);
break;
case hdr_append:
apr_table_mergen(r->headers_out, hdr->header, hdr->value);
break;
case hdr_set:
apr_table_setn(r->headers_out, hdr->header, hdr->value);
break;
case hdr_unset:
apr_table_unset(r->headers_out, hdr->header);
break;
}
}
}
static int fixup_headers(request_rec *r)
{
void *sconf = r->server->module_config;
headers_conf *serverconf =
(headers_conf *) ap_get_module_config(sconf, &headers_module);
void *dconf = r->per_dir_config;
headers_conf *dirconf =
(headers_conf *) ap_get_module_config(dconf, &headers_module);
do_headers_fixup(r, serverconf->headers);
do_headers_fixup(r, dirconf->headers);
return DECLINED;
}
static void register_hooks(apr_pool_t *p)
{
ap_hook_fixups(fixup_headers,NULL,NULL,AP_HOOK_MIDDLE);
}
module AP_MODULE_DECLARE_DATA headers_module =
{
STANDARD20_MODULE_STUFF,
create_headers_dir_config, /* dir config creater */
merge_headers_config, /* dir merger --- default is to override */
create_headers_config, /* server config */
merge_headers_config, /* merge server configs */
headers_cmds, /* command apr_table_t */
register_hooks /* register hooks */
};