feat(websocket): Add websocket HTTP redirect

 - Handle 301 status (moved permanently) and redirect the connection to the new host.

Author: glmfe

components/esp_websocket_client/esp_websocket_client.c

@@ -64,6 +64,12 @@ static const char *TAG = "websocket_client";
 #define WS_OVER_TCP_SCHEME  "ws"
 #define WS_OVER_TLS_SCHEME  "wss"
 #define WS_HTTP_BASIC_AUTH  "Basic "
+#define WS_HTTP_REDIRECT(code) ((code >= 300) && (code < 400))
+
+#if ESP_IDF_VERSION >= ESP_IDF_VERSION_VAL(5, 5, 0)
+// Features supported in 5.5.0
+#define WS_TRANSPORT_REDIRECT_HEADER_SUPPORT    1
+#endif
 
 const static int STOPPED_BIT = BIT0;
 const static int CLOSE_FRAME_SENT_BIT = BIT1;   // Indicates that a close frame was sent by the client
@@ -598,6 +604,23 @@ static esp_err_t esp_websocket_client_create_transport(esp_websocket_client_hand
     return ESP_OK;
 }
 
+static void esp_websocket_client_prepare_transport(esp_websocket_client_handle_t client)
+{
+    //get transport by scheme
+    if (client->transport == NULL && client->config->ext_transport == NULL) {
+        client->transport = esp_transport_list_get_transport(client->transport_list, client->config->scheme);
+    }
+
+    if (client->transport == NULL) {
+        ESP_LOGE(TAG, "There are no transports valid, stop websocket client");
+        client->run = false;
+    }
+    //default port
+    if (client->config->port == 0) {
+        client->config->port = esp_transport_get_default_port(client->transport);
+    }
+}
+
 static int esp_websocket_client_send_with_exact_opcode(esp_websocket_client_handle_t client, ws_transport_opcodes_t opcode, const uint8_t *data, int len, TickType_t timeout)
 {
     int ret = -1;
@@ -1022,19 +1045,7 @@ static void esp_websocket_client_task(void *pv)
     esp_websocket_client_handle_t client = (esp_websocket_client_handle_t) pv;
     client->run = true;
 
-    //get transport by scheme
-    if (client->transport == NULL && client->config->ext_transport == NULL) {
-        client->transport = esp_transport_list_get_transport(client->transport_list, client->config->scheme);
-    }
-
-    if (client->transport == NULL) {
-        ESP_LOGE(TAG, "There are no transports valid, stop websocket client");
-        client->run = false;
-    }
-    //default port
-    if (client->config->port == 0) {
-        client->config->port = esp_transport_get_default_port(client->transport);
-    }
+    esp_websocket_client_prepare_transport(client);
 
     client->state = WEBSOCKET_STATE_INIT;
     xEventGroupClearBits(client->status_bits, STOPPED_BIT | CLOSE_FRAME_SENT_BIT);
@@ -1072,6 +1083,26 @@ static void esp_websocket_client_task(void *pv)
                 esp_websocket_client_abort_connection(client, WEBSOCKET_ERROR_TYPE_TCP_TRANSPORT);
                 break;
             }
+#if WS_TRANSPORT_REDIRECT_HEADER_SUPPORT
+            else if (WS_HTTP_REDIRECT(result)) {
+                const char *redir = esp_transport_ws_get_redir_uri(client->transport);
+                if (redir) {
+                    // Redirecting to a new URI
+                    free(client->config->uri);
+
+                    client->config->uri = strdup(redir);
+                    client->config->port = 0;
+
+                    esp_websocket_client_set_uri(client, client->config->uri);
+                    esp_websocket_client_prepare_transport(client);
+
+                    // Rerun the connection with the redir uri.
+                    client->state = WEBSOCKET_STATE_INIT;
+                    ESP_LOGI(TAG, "Redirecting to %s", client->config->uri);
+                    break;
+                }
+            }
+#endif
             ESP_LOGD(TAG, "Transport connected to %s://%s:%d", client->config->scheme, client->config->host, client->config->port);
 
             client->state = WEBSOCKET_STATE_CONNECTED;