ESP32 Forum

Posted: **Wed Nov 17, 2021 8:23 am**

Hi,

In the esp-idf included example ws_echo_server.c I cannot understand how the server can send a message to the client without the client sending a request previously. The function

Code: Select all

trigger_async_send(httpd_handle_t handle, httpd_req_t *req)

requires the client to send a request first. Also, the function:

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 httpd_ws_send_frame(httpd_req_t *req, httpd_ws_frame_t *pkt)

requires a existing request to be received so I cannot just send a packet.

Can somebody please clear this up please.

Regards,
Luke

Posted: **Thu Nov 18, 2021 9:40 am**

You can use API

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esp_err_t httpd_ws_send_frame_async(httpd_handle_t hd, int fd, httpd_ws_frame_t *frame);

For this API, you need record the fd in the previous connection.

Posted: **Fri Nov 19, 2021 12:57 pm**

Thanks that did the trick

Posted: **Sun Jan 29, 2023 9:07 am**

but if we run this in loop then user can not send no more requests.. is possible to increase number of connections for client..? maybe to run with xTaskCreate.. will try and noticing.

Posted: **Fri Feb 03, 2023 11:39 am**

so yes it works with xtaskcreate and to save socket somewhere..

ESP32 Forum

Web socket - Send asynchronous message from server to client without request from client

Web socket - Send asynchronous message from server to client without request from client

Re: Web socket - Send asynchronous message from server to client without request from client

Re: Web socket - Send asynchronous message from server to client without request from client

Re: Web socket - Send asynchronous message from server to client without request from client

Re: Web socket - Send asynchronous message from server to client without request from client