CODEWITHSUNDEEP
phpwebsocket
Oliver M Grech
Oliver M Grech

Reputation: 3181

PHP Websocket Client - Keep connection open

I am using PHP-WSS in a laravel application and need to keep a websocket client open to receive various messages from the websocket server.

So far I built a CLI php script that I can execute and wait for messages to arrive.

I built the following function to test...

The question is, to keep the connection open for any messages that might be sent from the server, is it a good approach to do it as below using a while(true) loop? Is there anyway I can do this better? (To me it looks dirty and wish to improve it and do it properly)

function testWebsocketClient() {
    $url = 'wss://example.com/?token=xyz123456';
    $client = new WebSocketClient($url, new ClientConfig());
    while(true){
        sleep(5);
        $client->send('test');
        $return = $client->receive(); // test received OK
    }
    return $return;
}

UPDATE: Anyone using PHP-WSS I found a bug in Connection.php in broadCast method.

Original function tries to send on a dead connection, which shows the following error Empty read; connection dead? (Note the EOF = true)

public function broadCast(string $data): void
{
    foreach ($this->clients as $client) {
        if (is_resource($client) ) { // check if not yet closed/broken etc
            fwrite($client, $this->encode($data));
        } else {
            echo 'Skipping a closed connection';
        }
    }
}

I changed it to

public function broadCast(string $data): void
{
    foreach ($this->clients as $client) {
        //echo PHP_EOL. stream_get_status($client) .PHP_EOL;
        $clientMeta = ( stream_get_meta_data($client) );
        $clientEof = $clientMeta['eof'];
        if (is_resource($client) && $clientEof == false ) { // check if not yet closed/broken etc
            fwrite($client, $this->encode($data));
        } else {
            echo 'Skipping a closed connection';
        }
    }
}

Upvotes: 1

Views: 5203

Answers (2)

Oliver M Grech
Oliver M Grech

Reputation: 3181

After an entire week struggling with this I found a solution...

There is an error handler that throws an exception if the buffer is empty, thus bring the client to an end.

In WscMain.php file, inside protected function read method, remove/comment out (or change to your liking and needs) the following error handler (approx line 302)

if(false){ // added a false condition so the code within doesn't execute
    if (false && $buff === false ) {
        $metadata = stream_get_meta_data($this->socket);
        throw new ConnectionException(
            'Broken frame, read ' . strlen($data) . ' of stated '
            . $len . ' bytes.  Stream state: '
            . json_encode($metadata),
            CommonsContract::CLIENT_BROKEN_FRAME
        );
    }

    if (false && $buff === '') {
        //print_r($this->socket);
        
        $metadata = stream_get_meta_data($this->socket);
        throw new ConnectionException(
            'Empty read; connection dead?  Stream state: ' . json_encode($metadata). ' '.PHP_EOL.( (int) $this->socket ) ,
            CommonsContract::CLIENT_EMPTY_READ
        );
    }
}

PS: For my case, I also made a very small (1 sec) read timeout in the config, as follows. (This test function is being executed from a CLI PHP script)

function runWebsocketClientTest(){

    echo PHP_EOL;
    echo __FUNCTION__;
    echo PHP_EOL;
    $timeout = 1;
    $return = '';
    $config = new ClientConfig();
    $config->setTimeout($timeout);
    $client = new WebSocketClient('ws://localhost:8000', $config);

    while($client->isConnected()){
        if($client->isConnected()){ // this might be unnecessary 
            echo $client->receive();
        }
    }
    
}

Hope this helps someone and thanks to all those that assisted.

Upvotes: 0

Daniil Loban
Daniil Loban

Reputation: 4381

Since the php script that renders the page finishes execution, you need to implement websockets on the client itself using a js script

<?php 
   // here output your page
   wss_path = 'wss://example.com/?token=xyz123456';
?>

// JS script (see its working results in console by pressing `F12`)
<script>
  let socket = new WebSocket(<?= wss_path ?>);

  socket.onopen = function(e) {
    console.log('[open] Connection opened');
    socket.send("Hi! I am a new web-socket client.");
  };

  socket.onmessage = function(event) {
    const message = JSON.parse(event.data);
    console.log('From the server:', message);
  };

  socket.onclose = function(event) {
    if (event.wasClean) {
      console.log(`[close] Connetion closed clearly, code=${event.code} reason=${event.reason}`);
    } else {
      console.log('[close] Сonnection closed unexpectedly');
    }
  };

  socket.onerror = function(error) {
    console.log(`[error] ${error}`);
  };
</script>

Upvotes: 2

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