hello_mongoc.c

#include "URI.h"
#include <mongoc/mongoc.h>

int main(int argc, char const *argv[]) {
  // your MongoDB URI connection string
  const char *uri_string = MY_MONGODB_URI;
  // MongoDB URI created from above string
  mongoc_uri_t *uri;
  // MongoDB Client, used to connect to the DB
  mongoc_client_t *client;
  // Command to be sent, and reply
  bson_t *command, reply;
  // Error management
  bson_error_t error;
  // Misc
  char *str;
  bool retval;

  /*
   * Required to initialize libmongoc's internals
   */
  mongoc_init();

  /*
   * Optionally get MongoDB URI from command line
   */
  if (argc > 1) {
    uri_string = argv[1];
  }

  /*
   * Safely create a MongoDB URI object from the given string
   */
  uri = mongoc_uri_new_with_error(uri_string, &error);
  if (!uri) {
    fprintf(stderr,
            "failed to parse URI: %s\n"
            "error message:       %s\n",
            uri_string, error.message);
    return EXIT_FAILURE;
  }

  /*
   * Create a new client instance, here we use the uri we just built
   */
  client = mongoc_client_new_from_uri(uri);
  if (!client) {
    return EXIT_FAILURE;
  }

  /*
   * Register the application name so we can track it in the profile logs
   * on the server. This can also be done from the URI (see other examples).
   */
  mongoc_client_set_appname(client, "connect-example");

  /*
   * Do work. This example pings the database and prints the result as JSON
   * BCON == BSON C Object Notation
   */
  command = BCON_NEW("ping", BCON_INT32(1));

  // we run above command on our DB, using the client. We get reply and error
  // (if any)
  retval = mongoc_client_command_simple(client, "admin", command, NULL, &reply,
                                        &error);

  // mongoc_client_command_simple returns false and sets error if there are
  // invalid arguments or a server or network error.
  if (!retval) {
     printf("Error: %s\n", error.message);
    return EXIT_FAILURE;
  }

  // if we're here, there's a JSON response
  str = bson_as_json(&reply, NULL);
  printf("%s\n", str);
  printf("Pinged your deployment. You successfully connected to MongoDB!\n");

  /*
   * Clean up memory
   */
  bson_destroy(&reply);
  bson_destroy(command);
  bson_free(str);

  /*
   * Release our handles and clean up libmongoc
   */

  mongoc_uri_destroy(uri);
  mongoc_client_destroy(client);
  mongoc_cleanup();

  return EXIT_SUCCESS;
}