Add User-Agent and additional headers to esp_websocket_client (IDFGH-2193)

[djunod]

esp_websocket_client add the ability to:

• Change the User-Agent string.
• Specify additional connection headers.

[CLAassistant]

All committers have signed the CLA.

[djunod]

@igrr can I get this reviewed & merged? Thanks

[Alvin1Zhang]

@djunod Thanks for the contribution and sorry for not replying earlier.

[djunod]

@Alvin1Zhang merge conflicts resolved.

[Alvin1Zhang]

@djunod Thanks for the contribution, merged as 9200250, thank you.

[eang79]

Hi guys,

Silly question - how do you specify additional headers for websockets? I know that this is not the right place to ask but nobody seems to reply in the forum.

I tried to do it like this but it doesn't work with error shown below. I printed out the errors in the backend but there isn't an authorization key in the transaction leading to this failure.

websocket_cfg.uri = CONFIG_WEBSOCKET_URI;
const char *header = "{'authorization': 'Token abcdefg'}\r\n";
websocket_cfg.headers = header;
esp_websocket_client_handle_t client = esp_websocket_client_init(&websocket_cfg);
esp_websocket_register_events(client, WEBSOCKET_EVENT_ANY, websocket_event_handler, (void *)client);
esp_websocket_client_start(client);

I (5599) WEBSOCKET: Connecting to wss://anexample.ddns.net/...
E (23899) esp-tls: Failed to connnect to host (errno 113)
E (23899) esp-tls: Failed to open new connection
E (23899) TRANS_SSL: Failed to open a new connection
E (23899) TRANSPORT_WS: Error connecting to host anexample.ddns.net:443
E (23909) WEBSOCKET_CLIENT: Error transport connect

The function esp_transport_ws_set_headers() seems useful but its unclear how to use it. Also, specifying headers using a function in a lower-level layer seem to be incorrect.

Any tips or advice greatly appreciated, thanks!
Ed