Wrapping an object in a method

[NotionCommotion]

I have a class for streaming text.  My question has nothing to do with this particular, but how to modify an object.  Originally, I had functionality to deal JSON, but decided to remove that functionality as I felt it didn't belong there.  The class now looks like the following:

<?php
namespace Server;

use Evenement\EventEmitterInterface;
use Evenement\EventEmitterTrait;
use React\Stream\DuplexStreamInterface;

class LengthPrefixStream implements EventEmitterInterface {
    use EventEmitterTrait;

    private $socket=false,
    $buffer='';

    public function __construct(DuplexStreamInterface $socket){
        $this->socket = $socket;
        $this->socket->on('data', function($data){
            $this->buffer .= $data;
            $this->parseBuffer();
        });
    }

    public function send($message){
        //Still need to implement drain
        if($this->isConnected()) {
            $this->socket->write(pack("V", strlen($message)).$message);
            return true;
        }
        else {
            return false;
        }
    }

    private function parseBuffer(){
        do {
            $checkAgain = false;
            $bufferLength = strlen($this->buffer);
            $length = unpack('Vlen', substr($this->buffer, 0, 4))['len'];
            if($bufferLength >= $length + 4){
                $this->emit('data', [substr($this->buffer, 4, $length)]);
                $this->buffer = substr($this->buffer, $length+4);
                $checkAgain = strlen($this->buffer)>=4;
            } 
        } while ($checkAgain);
    }

    public function isConnected()
    {
        return $this->socket?true:false;
    }

    public function close()
    {
        $this->socket->close();
    }
}

I use it something like this:

    protected function sendCommand($text)
    {
        $data = false;
        $loop = new \React\EventLoop\StreamSelectLoop();
        $socket = new \React\SocketClient\TimeoutConnector(new \React\SocketClient\TcpConnector($loop), 15, $loop);
        $socket->create($this->host['url'], $this->host['port'])->then(function($stream) use (&$data, $loop, $text){
            $client = new \DataLogger\Server\LengthPrefixStream($stream);
            $client->on('data', function($data) use (&$data, $loop, $stream){
                //Passed by reference $data will be set.  Maybe need to use a separate variable?
                $stream->close();
                $loop->stop();
            });
            $client->send($text);
        });
        $loop->run();
        return $data;   //False on failure
    }

But now I wish to send and return variables other than text, and will need to convert them to JSON.

 

I still don't wish to put this functionality in the class.  Furthermore, I use this class more than one place, so don't wish to duplicate the JSON conversion and checking that it is valid JSON each time.

 

I am thinking I might be able to wrap the object in another method.

//$client = new \DataLogger\Server\LengthPrefixStream($stream);
$client = $this->wrapClient(new \DataLogger\Server\LengthPrefixStream($stream));

protected function wrapClient($client)
{
    /*
    Turn messages sent into JSON and verify that it is valid.
    Turn responses received into JSON and verify that it is valid.
    */
}

But I am kind of at a lose where to go next.

 

Any suggestions?

[NotionCommotion]

Or maybe I should be wrapping it not in a method, but another class?  The send() method seems okay, but not the on() method.

 

The reason I tried to get away from having the json scope in the LengthPrefixStream class is I wish to log json errors, and didn't want to pass a logger into a generic class.  Guess I will need to do the same if I use this approach...

$client = new wrapClient(new \DataLogger\Server\LengthPrefixStream($stream));

class wrapClient
{
    public function __construct($client){
        $this->client = $client;
    } 
    public function send($msg)
    {
        $this->client->send(json_encode($msg));
    }

    public function on($msg)
    {
        $o = json_decode($msg);
        if (json_last_error() != JSON_ERROR_NONE){
            $rsp='ERROR: Invalid JSON provided';
        }
        return o;
    }
}

 

[kicken]

You could try implementing a stream wrapper but not sure how well that'd work with react/json.

 

Your wrapping class sounds more or less like my JSONStream class from an earlier example.

[NotionCommotion]

Your wrapping class sounds more or less like my JSONStream class from an earlier example.

 

Almost...  Yours worked!

 

Maybe I put the on method in the constructor like you did.

 

Or maybe I just go back to putting this json functionality in the class like you did, and pass back some message if json isn't valid.

[NotionCommotion]

Actually, what I will do is put the json scope in the class, but through an exception upon invalid json.