Read POST parameters from apache module - c

Question

I'm trying to read POST parameters from an apache c module.
Here's the code I'm using :
/* Include the required headers from httpd */
#include "httpd.h"
#include "http_core.h"
#include "http_protocol.h"
#include "http_request.h"
#include "http_config.h"
#include "apr_strings.h"
#include "apr_network_io.h"
#include "apr_dbd.h"
#include <apr_file_info.h>
#include <apr_file_io.h>
#include <apr_tables.h>
#include "util_script.h"
/* Define prototypes of our functions in this module */
typedef struct {
const char *key;
const char *value;
} keyValuePair;
static void register_hooks(apr_pool_t *pool);
static int example_handler(request_rec *r);
keyValuePair *readPost(request_rec *r);
/* Define our module as an entity and assign a function for registering hooks */
module AP_MODULE_DECLARE_DATA example_module =
{
STANDARD20_MODULE_STUFF,
NULL, // Per-directory configuration handler
NULL, // Merge handler for per-directory configurations
NULL, // Per-server configuration handler
NULL, // Merge handler for per-server configurations
NULL, // Any directives we may have for httpd
register_hooks // Our hook registering function
};
/* register_hooks: Adds a hook to the httpd process */
static void register_hooks(apr_pool_t *pool)
{
/* Hook the request handler */
ap_hook_handler(example_handler, NULL, NULL, APR_HOOK_LAST);
}
/* The handler function for our module.
* This is where all the fun happens!
*/
static int example_handler(request_rec *r)
{
/* First off, we need to check if this is a call for the "example" handler.
* If it is, we accept it and do our things, it not, we simply return DECLINED,
* and Apache will try somewhere else.
*/
if (!r->handler || strcmp(r->handler, "example-handler")) return (DECLINED);
// The first thing we will do is write a simple "Hello, world!" back to the client.
ap_rputs("Hello, world!<br/>", r);
return OK;
}
keyValuePair *readPost(request_rec *r) {
apr_array_header_t *pairs = NULL;
apr_off_t len;
apr_size_t size;
int res;
int i = 0;
char *buffer;
keyValuePair *kvp;
res = ap_parse_form_data(r, NULL, &pairs, -1, HUGE_STRING_LEN);
if (res != OK || !pairs) return NULL; /* Return NULL if we failed or if there are is no POST data */
kvp = apr_pcalloc(r->pool, sizeof(keyValuePair) * (pairs->nelts + 1));
while (pairs && !apr_is_empty_array(pairs)) {
ap_form_pair_t *pair = (ap_form_pair_t *) apr_array_pop(pairs);
apr_brigade_length(pair->value, 1, &len);
size = (apr_size_t) len;
buffer = apr_palloc(r->pool, size + 1);
apr_brigade_flatten(pair->value, buffer, &size);
buffer[len] = 0;
kvp[i].key = apr_pstrdup(r->pool, pair->name);
kvp[i].value = buffer;
ap_rputs(kvp[i].key,r);
ap_rputs(kvp[i].value,r);
i++;
}
return kvp;
}
I have copied the read post function from the apache website:
https://httpd.apache.org/docs/2.4/developer/modguide.html#snippets
I get the following error while trying to compile the module:
mod_example.c:82:9: error: use of undeclared identifier
'ap_form_pair_t'
ap_form_pair_t *pair = (ap_form_pair_t *) apr_array_pop(pairs);
apxs does not recognize ap_form_pair_t. Am I missing any header file ?
Can you please help me resolve this ?

Answer 1

ap_form_pair_t comes with apache version 2.4, so I think you use a lower version.
This function writes all post data in a buffer, it may help you:
int util_read(request_rec *r, char **rbuf, size_t &length){
int rc;
length = 0;
if((rc = ap_setup_client_block(r, REQUEST_CHUNKED_ERROR)) != OK){
return rc;
}
if(ap_should_client_block(r)){
char argsbuffer[HUGE_STRING_LEN];
int rsize, len_read, rpos=0;
length = r->remaining;
*rbuf = (char*)apr_pcalloc(r->pool, length + 1);
while((len_read = ap_get_client_block(r, argsbuffer, sizeof(argsbuffer))) > 0){
if((rpos + len_read) > length){
rsize = length - rpos;
} else {
rsize = len_read;
}
memcpy((char*)*rbuf + rpos, argsbuffer, rsize);
rpos += rsize;
}
}
return rc;
}