libmicrohttpd

HTTP/1.x server C library (MHD 1.x, stable)
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querystring_example.c (3957B)

      1 /*
      2      This file is part of libmicrohttpd
      3      Copyright (C) 2007, 2008 Christian Grothoff (and other contributing authors)
      4      Copyright (C) 2016-2022 Evgeny Grin (Karlson2k)
      5 
      6      This library is free software; you can redistribute it and/or
      7      modify it under the terms of the GNU Lesser General Public
      8      License as published by the Free Software Foundation; either
      9      version 2.1 of the License, or (at your option) any later version.
     10 
     11      This library is distributed in the hope that it will be useful,
     12      but WITHOUT ANY WARRANTY; without even the implied warranty of
     13      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     14      Lesser General Public License for more details.
     15 
     16      You should have received a copy of the GNU Lesser General Public
     17      License along with this library; if not, write to the Free Software
     18      Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
     19 */
     20 /**
     21  * @file querystring_example.c
     22  * @brief example for how to get the query string from libmicrohttpd
     23  *        Call with an URI ending with something like "?q=QUERY"
     24  * @author Christian Grothoff
     25  * @author Karlson2k (Evgeny Grin)
     26  */
     27 
     28 #include "platform.h"
     29 #include <microhttpd.h>
     30 
     31 #define PAGE \
     32   "<html><head><title>libmicrohttpd demo</title></head><body>Query string for &quot;%s&quot; was &quot;%s&quot;</body></html>"
     33 
     34 static enum MHD_Result
     35 ahc_echo (void *cls,
     36           struct MHD_Connection *connection,
     37           const char *url,
     38           const char *method,
     39           const char *version,
     40           const char *upload_data, size_t *upload_data_size, void **req_cls)
     41 {
     42   static int aptr;
     43   const char *val;
     44   char *me;
     45   struct MHD_Response *response;
     46   enum MHD_Result ret;
     47   int resp_len;
     48   size_t buf_size;
     49   (void) cls;               /* Unused. Silent compiler warning. */
     50   (void) url;               /* Unused. Silent compiler warning. */
     51   (void) version;           /* Unused. Silent compiler warning. */
     52   (void) upload_data;       /* Unused. Silent compiler warning. */
     53   (void) upload_data_size;  /* Unused. Silent compiler warning. */
     54 
     55   if (0 != strcmp (method, "GET"))
     56     return MHD_NO;              /* unexpected method */
     57   if (&aptr != *req_cls)
     58   {
     59     /* do never respond on first call */
     60     *req_cls = &aptr;
     61     return MHD_YES;
     62   }
     63   *req_cls = NULL;  /* reset when done */
     64   val = MHD_lookup_connection_value (connection, MHD_GET_ARGUMENT_KIND, "q");
     65   if (NULL == val)
     66     return MHD_NO;  /* No "q" argument was found */
     67   resp_len = snprintf (NULL, 0, PAGE, "q", val);
     68   if (0 >= resp_len)
     69     return MHD_NO;  /* Error calculating response size */
     70   buf_size = (size_t) resp_len + 1; /* Add one byte for zero-termination */
     71   me = malloc (buf_size);
     72   if (me == NULL)
     73     return MHD_NO;  /* Error allocating memory */
     74   if (resp_len != snprintf (me, buf_size, PAGE, "q", val))
     75   {
     76     free (me);
     77     return MHD_NO;  /* Error forming the response body */
     78   }
     79   response =
     80     MHD_create_response_from_buffer_with_free_callback (buf_size - 1,
     81                                                         (void *) me,
     82                                                         &free);
     83   if (response == NULL)
     84   {
     85     free (me);
     86     return MHD_NO;
     87   }
     88   ret = MHD_queue_response (connection, MHD_HTTP_OK, response);
     89   MHD_destroy_response (response);
     90   return ret;
     91 }
     92 
     93 
     94 int
     95 main (int argc, char *const *argv)
     96 {
     97   struct MHD_Daemon *d;
     98   int port;
     99 
    100   if (argc != 2)
    101   {
    102     printf ("%s PORT\n", argv[0]);
    103     return 1;
    104   }
    105   port = atoi (argv[1]);
    106   if ( (port < 0) ||
    107        (port > UINT16_MAX) )
    108   {
    109     printf ("%s PORT\n", argv[0]);
    110     return 1;
    111   }
    112   d = MHD_start_daemon (MHD_USE_THREAD_PER_CONNECTION
    113                         | MHD_USE_INTERNAL_POLLING_THREAD | MHD_USE_ERROR_LOG,
    114                         (uint16_t) port,
    115                         NULL, NULL, &ahc_echo, NULL, MHD_OPTION_END);
    116   if (NULL == d)
    117     return 1;
    118   (void) getc (stdin);
    119   MHD_stop_daemon (d);
    120   return 0;
    121 }