CODEWITHSUNDEEP
phpsockets
Adrian Maire
Adrian Maire

Reputation: 14815

php: How to save the client socket (not closed), so a further script may retrieve it to send an answer?

I have a client-server application, in which the server may require to send information back to clients.

As the client-server pattern does not allow the server to "request" the client, there are 2 solutions:

Currently, the client (Web app with JavaScript and Html/Css) open a streaming connection to the server (A C++ server) which may send information back to the client.

I would like to implement a PHP version of this feature to allow low-cost hosting to work with my program (low-cost hosting usually does not provide access to install/run binaries). The idea is that the client make a request that establish the streaming socket, it save the socket and then, an other request may retrieve this socket and send new information through it.

So, my question is: How to save an http socket in PHP, so a further request may retrieve it?

I do not know even if that is possible, I read about pfsockopen, but it seem a bit different to what I need ( I may be wrong ).

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Upvotes: 3

Views: 1542

Answers (2)

vp_arth
vp_arth

Reputation: 14982

So, you need two connections for each client, one persist for get data from server, and other to send data to.

Something like:

in persist.php: 

$socket = stream_socket_server('unix:///tmp/unique.sock', $errno, $errstr);
if (!$socket) {
  echo "$errstr ($errno)<br />\n";
} else {
  while ($conn = stream_socket_accept($socket)) {
    $buffer = "";
    // Read until double CRLF
    while( !preg_match('/\r?\n\r?\n/', $buffer) )
        $buffer .= fread($client, 2046); 

    //Operate with our listener
    echo $buffer;
    flush();

    // Respond to socket client
    fwrite($conn,  "200 OK HTTP/1.1\r\n\r\n");
    fclose($conn);
  }
  fclose($socket);
}

in senddata.php:

$sock = stream_socket_client('unix:///tmp/unique.sock', $errno, $errstr);
fwrite($sock, $data);
fflush($sock);
fclose($sock);

Upvotes: 1

vp_arth
vp_arth

Reputation: 14982

One way to solve it - forget about sockets.

Pseudocode:

// receive request, set some session_id if not exists
// request contains last_timestamp, so we know which data client already have
// check have we any dataset for this session_id after last_timestamp
// return this dataset, or no_new_data signature

Data can be stored in database, for example.

Upvotes: 0

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