CloudAMQP with C Getting started

Recommended C client for RabbitMQ is the Rabbitmq-c client library . The library is maintained by alanxz.

The sample code below show how to set up a connection to CloudAMQP and how to set up a listener for messages. The code below is build upon the example given in the example folder for the lib, amqp_listen.c, additional information is added to show how to set up the CloudAMQP credentials. An important part for users on shared plans is to set channel_max to something else then 0. amqp_login(conn, vhost, channel_max, frame_max,heartbeat, AMQP_SASL_METHOD_PLAIN, user, password),"Logging in");
(A request to change the library is sent to the creator of the library. 0 is equal to unlimited, and that will result in errors with CloudAMQPs channel_max limit on the shared plans.)

More information about the library can be found here: http://alanxz.github.io/rabbitmq-c/docs/0.2/annotated.html

//amqp_listen.c

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <amqp_tcp_socket.h>
#include <amqp.h>
#include <amqp_framing.h>
#include <assert.h>
#include "utils.h"

int main(int argc, char const *const *argv)
{
  char const *hostname, *vhost, *password, *username;
  int port, status;
  char const *exchange;
  char const *bindingkey;
  amqp_socket_t *socket = NULL;
  amqp_connection_state_t conn;

  amqp_bytes_t queuename;

  hostname = "hostname"; //bunny.cloudamqp.com
  port = 5672;
  exchange = "amq.direct";
  bindingkey = "test";
  vhost = "vhost";
  username = "username"
  password = "password";

  conn = amqp_new_connection();

  socket = amqp_tcp_socket_new(conn);
  if (!socket) { die("creating TCP socket"); }

  status = amqp_socket_open(socket, hostname, port);
  if (status) { die("opening TCP socket"); }

  die_on_amqp_error(amqp_login(conn, vhost, 200, 131072, 0, AMQP_SASL_METHOD_PLAIN, username, password), "Logging in");

  amqp_channel_open(conn, 1);
  die_on_amqp_error(amqp_get_rpc_reply(conn), "Opening channel");
  {
    amqp_queue_declare_ok_t *r = amqp_queue_declare(conn, 1, amqp_empty_bytes, 0, 0, 0, 1, amqp_empty_table);
    die_on_amqp_error(amqp_get_rpc_reply(conn), "Declaring queue");
    queuename = amqp_bytes_malloc_dup(r->queue);
    if (queuename.bytes == NULL) {
      fprintf(stderr, "Out of memory while copying queue name");
      return 1;
    }
  }

  amqp_queue_bind(conn, 1, queuename, amqp_cstring_bytes(exchange), amqp_cstring_bytes(bindingkey), amqp_empty_table);
  die_on_amqp_error(amqp_get_rpc_reply(conn), "Binding queue");

  amqp_basic_consume(conn, 1, queuename, amqp_empty_bytes, 0, 1, 0, amqp_empty_table);
  die_on_amqp_error(amqp_get_rpc_reply(conn), "Consuming");
  {
    while (1) {
      amqp_rpc_reply_t res;
      amqp_envelope_t envelope;
      amqp_maybe_release_buffers(conn);
      res = amqp_consume_message(conn, &envelope, NULL, 0);
      if (AMQP_RESPONSE_NORMAL != res.reply_type) {
        break;
      }
      printf("Delivery %u, exchange %.*s routingkey %.*s\n",
        (unsigned)envelope.delivery_tag,
        (int)envelope.exchange.len, (char *)envelope.exchange.bytes,
        (int)envelope.routing_key.len, (char *)envelope.routing_key.bytes);

      if (envelope.message.properties._flags & AMQP_BASIC_CONTENT_TYPE_FLAG) {
        printf("Content-type: %.*s\n",
          (int)envelope.message.properties.content_type.len,
          (char *)envelope.message.properties.content_type.bytes);
      }
      printf("----\n");
      amqp_dump(envelope.message.body.bytes, envelope.message.body.len);
      amqp_destroy_envelope(&envelope);
    }
  }

  die_on_amqp_error(amqp_channel_close(conn, 1, AMQP_REPLY_SUCCESS), "Closing channel");
  die_on_amqp_error(amqp_connection_close(conn, AMQP_REPLY_SUCCESS), "Closing connection");
  die_on_error(amqp_destroy_connection(conn), "Ending connection");
  return 0;
}