niMQTT's usage

Page last updated 14 Aug 2013, by Guilhem Saurel. 4 replies

niMQTT is an MQTT library designed for the new EthernetInteface lib.

Import libraryniMQTT

An MQTT Client for the new etherNet Interface.

Last commit 13 Aug 2013 by Guilhem Saurel

To use it, you only need a callback with the prototype

callback

void callback(const char *topic, const char *message)

Once you have it, you can create your MQTT's client following this prototype:

niMQTT Client prototype

niMQTT(char *server, void (*callback)(const char *, const char*), char *id="mbed", int port=1883, char *username="", char *password="", bool debug=false);

On creating an instance, a Thread will listen and call your callback when necessary, and you can meanwhile:

  • subscribe to a topic:

subscribe

client.sub("topic");
  • unsubscribe:

unsubscribe

client.sub("topic", true);
  • publish a message to a topic:

publish

client.pub("topic", "message");

You can see this example as a starting point:

Import programniMQTT_example

An exemple for the lib niMQTT

Last commit 13 Aug 2013 by Guilhem Saurel

4 comments on niMQTT's usage:

Amrita IOT
14 Aug 2013

hai there,

I tried this program to connect to an MQTT server running on java. But I failed to establish the connection. The serial terminal shows, Connection... Socket connection... Socket connection... Socket connection... ............................. The code is stuck @ do printf("Socket connection...\r\n"); while (socket->connect(server, port) < 0); socket->set_blocking(true, KEEP_ALIVE*500); KEEP_ALIVE / 2 in seconds please help me with this..... Regards.............Bimal

Guilhem Saurel
14 Aug 2013

Hi,

Amrita IOT wrote:

The code is stuck @ do printf("Socket connection...\r\n"); while (socket->connect(server, port) < 0); socket->set_blocking(true, KEEP_ALIVE*500); KEEP_ALIVE / 2 in seconds please help me with this..... Regards.............Bimal

well, if your socket can't connect to (server, port), it probably means that your port and/or your ip is not good, or there is a network issue between your server and your mbed.

Amrita IOT
19 Aug 2013

Guilhem Saure, Thank you for the response. I will check it. But my mbed works well in establishing a TCP connection to a different remote server using example TCP_example and sending some text also. But when I try to connect to the MQTT server @ port 1833, TCP connection is failing........

Benjamin Cabé
11 Sep 2013

Are you sure your server is listening on all the interfaces and not only localhost/127.0.0.1?

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