Working on MQTT, a machine-to-machine (M2M) "Internet of Things" connectivity protocol.

What should an mbed MQTT API look like?

08 Jan 2015

Dear Ian, Thanks for your reply. I also have some other questions about mbed/IBM MQTT open souece. IBM paho project(an IOT open source project) has released some types of MQTT open source code:c posix/c++ posic/c embeded/java.It seems the posix and java versions more mature. The mbed MQTT open srouce seems generating from paho MQTT c embeded source. Does your mbed MQTT source code will be used in fututure mbed official version?

the current mbed MQTT has some disadwantages: 1.Async API are not ready. 2.Has not think of SSL/TLS or any interfaces,SSL 3.No official test case and updates,seems only you contributes that code

That is not your fault,since the Mbed official has provide SSL/TLS interface and No MQTT test/development plan.

But the C posix version seems more attractive.It use the posix os api,Async API,aslo support SSL based on Open SSL. So, which MQTT version do you suggest me use? and which version will the Mbed official MQTT based on? thanks.

14 Jan 2015

Hi Terrence,

the Paho Posix C client does include SSL/TLS support but:

a) requires OpenSSL which is not available on mbed b) uses Linux or Windows system APIs, so in general is restricted to Linux or Windows systems c) freely uses memory allocations and frees, so is not good for very small amounts of memory normally found on microcontrollers

So the Paho Posix C client is not suitable for mbed, but is for Linux or Windows. The embedded C/C+ client, or mbed MQTT client:

1) No, the asynchronous API is not ready, agreed. 2) Yes I have thought of SSL/TLS interfaces, and you can use them. The code does not use any particular network APIs so you can plug in your own. I have written an application using TLS on mbed, but the TLS library is GPL, so we had a problem providing the code. I will write about this soon. 3) I believe this library will be the basis of an official Mbed MQTT API, yes.

For mbed, you should use the embedded client.


15 Jan 2015

Dear Ian, Thanks for your reply in detail.

23 Nov 2015


Is the sync- c++ APIs are ready now. what is the footprint of the complete library.


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