Ecore_Con_Url - Managing cookies

This example shows how to use an Ecore_Con_Url and enable it to receive/send cookies.

These cookies can be set by the server, saved to a file, loaded later from this file and sent again to the server. The complete example can be found at ecore_con_url_cookies_example.c

First we are setting some callbacks for events that will be sent when data arrives in our connection (the data is the content of the file being downloaded), and when the download is completed. The _url_data_cb and _url_complete_cb are these callbacks:

static Eina_Bool
_url_progress_cb(void *data EINA_UNUSED, int type EINA_UNUSED, void *event_info)
{
   Ecore_Con_Event_Url_Progress *url_progress = event_info;
   float percent;
 
   if (url_progress->down.total > 0)
     {
        struct _request *req = ecore_con_url_data_get(url_progress->url_con);
        req->size = url_progress->down.now;
 
        percent = (url_progress->down.now / url_progress->down.total) * 100;
        printf("Total of download complete: %0.1f (%0.0f)%%\n",
               percent, url_progress->down.now);
     }
 
   printf("status: %d\n", ecore_con_url_status_code_get(url_progress->url_con));
 
   return EINA_TRUE;
}
 
static Eina_Bool
_url_complete_cb(void *data EINA_UNUSED, int type EINA_UNUSED, void *event_info)
{
   Ecore_Con_Event_Url_Complete *url_complete = event_info;
 
   struct _request *req = ecore_con_url_data_get(url_complete->url_con);
   int nbytes = ecore_con_url_received_bytes_get(url_complete->url_con);
 
   printf("\n");
   printf("download completed with status code: %d\n", url_complete->status);
   printf("Total size of downloaded file: %ld bytes\n", req->size);
   printf("Total size of downloaded file: %d bytes "
          "(from received_bytes_get)\n", nbytes);
   ecore_main_loop_quit();
 
   return EINA_TRUE;
}

In the main function we parse some parameter from the command line. These parameters are the url that we are connecting to, and cookie use policy.

After that we initialize the libraries and create a handler to our request using the given url:

 
int
main(int argc, const char *argv[])
{
   Ecore_Con_Url *ec_url = NULL;
   struct _request *req;
   int fd;
   const char *filename = "downloadedfile.dat";
 
   if (argc < 2)
     {
        printf("need one parameter: <url>\n");
        return -1;
     }
 
   fd = open(filename, O_CREAT | O_BINARY | O_WRONLY | O_TRUNC, 0644);
 
   if (fd == -1)
     {
        printf("error: could not open file for writing: \"%s\"\n",
               filename);
        return -1;
     }
 
   ecore_init();
   ecore_con_init();
   ecore_con_url_init();
 
   ec_url = ecore_con_url_new(argv[1]);
   if (!ec_url)
     {
        printf("error when creating ecore con url object.\n");
        goto end;
     }

We also set the event handlers for this request and add a header to it, that will inform our custom user agent:

Now we start playing with cookies. First, let's call ecore_con_url_cookies_init() to inform that we want cookies enabled. We also set a file from which we are loading previously set (old) cookies, in case that we don't want to clear old cookies or old session cookies.

After that we set the file where we are going to save all valid cookies in the Ecore_Con_Url object. This includes previously loaded cookies (that weren't cleared) and new cookies set by the response header "Set-Cookie" that comes with the response to our request:

And finally, before performing the request, we check the command passed as argument in the command line and use it to choose between clearing old cookies, clearing just old session cookies, or ignoring old session cookies.

After that we just finish our code as expected:

Notice that in this code, if we want to clear old cookies, we also don't load them from the file. This is a bit confusing and the API isn't clear, but ecore_con_url_cookies_file_add() will load cookies from the specified files just when the operation is really performed (i.e. ecore_con_url_get() is called). So if ecore_con_url_cookies_clear() is called before ecore_con_url_get(), the old cookies may not have been loaded yet, so they are not cleared. To avoid having old cookies loaded, don't add any cookie file with ecore_con_url_cookies_file_add().

The function ecore_con_url_cookies_clear() is just useful to clear cookies that are already loaded/valid in the Ecore_Con_Url object (from a previous request, for example).