esp_http_server: Add httpd_ws_get_fd_info() API to check active WS clients

Added a new API to WebSocket server to test provided socket descriptor if it belongs to active clients for this server and if websocket handshake has been performed

Closes https://github.com/espressif/esp-idf/issues/5602

components/esp_http_server/include/esp_http_server.h

@@ -1586,6 +1586,19 @@ esp_err_t httpd_ws_send_frame(httpd_req_t *req, httpd_ws_frame_t *pkt);
  */
 esp_err_t httpd_ws_send_frame_async(httpd_handle_t hd, int fd, httpd_ws_frame_t *frame);
 
+/**
+ * @brief Checks the supplied socket descriptor if it belongs to any active client
+ * of this server instance and if the websoket protocol is active
+ *
+ * @param[in] hd      Server instance data
+ * @param[in] fd      Socket descriptor
+ * @return
+ *  - -1                    : This fd is not a client of this httpd
+ *  - 0                     : This fd is an active client, protocol is not WS
+ *  - 1                     : This fd is an active client, protocol is WS
+ */
+int httpd_ws_get_fd_info(httpd_handle_t hd, int fd)
+
 #endif /* CONFIG_HTTPD_WS_SUPPORT */
 /** End of WebSocket related stuff
  * @}

components/esp_http_server/src/httpd_ws.c

@@ -383,4 +383,15 @@ esp_err_t httpd_ws_get_frame_type(httpd_req_t *req)
     return ESP_OK;
 }
 
+int httpd_ws_get_fd_info(httpd_handle_t hd, int fd)
+{
+    struct sock_db *sess = httpd_sess_get(hd, fd);
+
+    if (sess == NULL) {
+        return -1;
+    }
+    bool is_active_ws = sess->ws_handshake_done && (!sess->ws_close);
+    return is_active_ws ? 1 : 0;
+}
+
 #endif /* CONFIG_HTTPD_WS_SUPPORT */