libmicrohttpd/doc/examples/responseheaders.c

#include <microhttpd.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>

#define PORT 8888
#define FILENAME "picture.png"
#define MIMETYPE "image/png"


long get_file_size (const char *filename)
{
  FILE *fp;
  
  fp = fopen (filename, "rb");
  if (fp) 
    {
      long size;

      if ( (0 != fseek (fp, 0, SEEK_END)) 
           || (-1 == (size = ftell (fp))) )
        size = 0;
   
      fclose (fp);

      return size;
    } 
  else 
    return 0;
}


int answer_to_connection (void *cls, struct MHD_Connection *connection, const char *url, 
                          const char *method, const char *version, const char *upload_data, 
                          unsigned int *upload_data_size, void **con_cls)
{
  unsigned char *buffer = NULL;
  struct MHD_Response *response;
  long size;
  FILE *fp;
  int ret = 0;

  if (0 != strcmp(method, "GET")) return MHD_NO;

  size = get_file_size (FILENAME);
  if (size != 0)
    {
      fp = fopen (FILENAME, "rb");
      if (fp) 
        {
          buffer = malloc (size);
      
            if (buffer)
              if (size == fread (buffer, 1, size, fp)) ret = 1;
      
          fclose(fp);
        }     
    }

  if (!ret) 
    {
      const char *errorstr = "<html><body>An internal server error has occured!\
                              </body></html>";

      if (buffer) free(buffer);
    
      response = MHD_create_response_from_data(strlen(errorstr), (void*)errorstr,
                                               MHD_NO, MHD_NO);

      if (response)
        {     
          ret = MHD_queue_response (connection, MHD_HTTP_INTERNAL_SERVER_ERROR, response);
          MHD_destroy_response (response);

          return MHD_YES;    
        } 
      else return MHD_NO;
    }

  response = MHD_create_response_from_data (size, (void*)buffer, MHD_YES, MHD_NO);

  MHD_add_response_header (response, "Content-Type", MIMETYPE);

  ret = MHD_queue_response (connection, MHD_HTTP_OK, response);
  MHD_destroy_response (response);

  return ret;
}


int main ()
{
  struct MHD_Daemon *daemon;

  daemon = MHD_start_daemon (MHD_USE_SELECT_INTERNALLY, PORT, NULL, NULL, 
                             &answer_to_connection, NULL, MHD_OPTION_END);
  if (NULL == daemon) return 1;

  getchar (); 

  MHD_stop_daemon (daemon);

  return 0;
}