Method sendHeader

src/utility/WebSocketsClient.cpp:460–545

* send the WebSocket header to Server * @param client WSclient_t * ptr to the client struct */

 * @param client WSclient_t *  ptr to the client struct
 */
void WebSocketsClient::sendHeader(WSclient_t * client) {

    static const char * NEW_LINE = "\r\n";

    DEBUG_WEBSOCKETS("[WS-Client][sendHeader] sending header...\n");

    uint8_t randomKey[16] = { 0 };

    for(uint8_t i = 0; i < sizeof(randomKey); i++) {
        randomKey[i] = random(0xFF);
    }

    client->cKey = base64_encode(&randomKey[0], 16);

#ifndef NODEBUG_WEBSOCKETS
    unsigned long start = micros();
#endif

    String handshake;
    bool ws_header = true;
    String url = client->cUrl;

    if(client->isSocketIO) {
        if(client->cSessionId.length() == 0) {
            url += WEBSOCKETS_STRING("&transport=polling");
            ws_header = false;
        } else {
            url += WEBSOCKETS_STRING("&transport=websocket&sid=");
            url += client->cSessionId;
        }
    }

    handshake = WEBSOCKETS_STRING("GET ");
    handshake += url + WEBSOCKETS_STRING(" HTTP/1.1\r\n"
            "Host: ");
    handshake += _host + ":" + _port + NEW_LINE;

    if(ws_header) {
        handshake += WEBSOCKETS_STRING("Connection: Upgrade\r\n"
                "Upgrade: websocket\r\n"
                "Sec-WebSocket-Version: 13\r\n"
                "Sec-WebSocket-Key: ");
        handshake += client->cKey + NEW_LINE;

        if(client->cProtocol.length() > 0) {
            handshake += WEBSOCKETS_STRING("Sec-WebSocket-Protocol: ");
            handshake += client->cProtocol + NEW_LINE;
        }

        if(client->cExtensions.length() > 0) {
            handshake += WEBSOCKETS_STRING("Sec-WebSocket-Extensions: ");
            handshake += client->cExtensions + NEW_LINE;
        }
    } else {
        handshake += WEBSOCKETS_STRING("Connection: keep-alive\r\n");
    }

    // add extra headers; by default this includes "Origin: file://"