How to do Custom Authentication in http header for MQTT-over-Websocket using C++ SDK?

Question

Hi,  
For "MQTT over WebSockets" found in [https://docs.aws.amazon.com/iot/latest/developerguide/custom-auth.html](), the credential can be passed  "Through request headers or query parameters in the HTTP UPGRADE request to establish the WebSockets connection."

Does anyone know how to do this using the AWS IoT SDK C++?
I understand that I can use Mqtt::OnWebSocketHandshakeIntercept() to embed authorisation into the HTTP header. However, it is unclear how it can be done since Http::HttpHeader basically only has name and value data members or is there another way to do it?

Any assistance is greatly appreciated,  
Andi

Accepted Answer

Hi,

The AWS IoT Device SDK for C++ v2 supports the process for custom authorizers. You can modify the pubsub sample  to test. Essentially set websocket to true, and then change the protocol as referenced [here](https://github.com/aws/aws-iot-device-sdk-cpp-v2/blob/aee303e577ccda67e41bd220b46943a6828a861f/samples/mqtt/raw_pub_sub/main.cpp#L87). This should then pass the additional HTTP Headers to the Custom Authorizer. The additional `authParam` headers are processed [here](https://github.com/aws/aws-iot-device-sdk-cpp-v2/blob/aee303e577ccda67e41bd220b46943a6828a861f/samples/mqtt/raw_pub_sub/main.cpp#L218).

I haven't tested with C++, so please do respond if you are successful or not.

Edit: The above method would be for request headers used by POST or GET. Query headers could also be used by modifying the URI while still changing the protocol name.

Answer

Many thanks, Gavin! I have tried it and it is working well for me.

How to do Custom Authentication in http header for MQTT-over-Websocket using C++ SDK?

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