(PHP 4, PHP 5, PHP 7, PHP 8)

pfsockopenOpen persistent Internet or Unix domain socket connection


    string $hostname,
    int $port = -1,
    int &$error_code = null,
    string &$error_message = null,
    ?float $timeout = null
): resource|false

This function behaves exactly as fsockopen() with the difference that the connection is not closed after the script finishes. It is the persistent version of fsockopen().


For parameter information, see the fsockopen() documentation.

Return Values

pfsockopen() returns a file pointer which may be used together with the other file functions (such as fgets(), fgetss(), fwrite(), fclose(), and feof()), or false on failure.


Version Description
8.0.0 timeout is nullable now.

See Also

  • fsockopen() - Open Internet or Unix domain socket connection

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User Contributed Notes 6 notes

11 years ago
pfsockopen() works great on IIS/Windows7 installation, it keeps connection open which is good for performance. However, there is one caveat: when connection is broken because of physical net failure, pfsockopen() returns handle as if connection was working. Subsequent call to fwrite() returns false so you have information about error. The problem is that after physical net connection is restored the situation doesn't change: pfsockopen() still returns handle and fwrite() returns false. In other words, PHP sticks to old connection that is not working (if you use fsockopen() instead, it will connect properly). Situation goes back to normal after 30 minutes when PHP closes unused connection.
The solution to this problem is to call fclose() on socket handle when fwrite() returns false.
k dot andris at gmail dot com
14 years ago
To see if it's really a new connection, or a reused one, you can use ftell() - and see if ther's been any traffic on the connection. If it's more than 0, then it's a reused connection.
php dot net at domainofdarkness dot com
22 years ago
OK, WRT to the p* functions opening a new connection when one already exists. It is my understanting that (under Apache anyways) this is on a per-process basis. If you do a 'ps auxw|grep httpd' on your server you will see more than one process. What p* does is make a p-connection on one of those processes only, the one that actually handles your request. Chances are that when you hit the page again it will be answered by a different process. I'm guessing if you keep hitting reload you'll get around to the original process again and there will be no error message or second connection open. Anyhow, this is true of all p* functions; they open not one connection per server, but one connection per server _process_.
pulstar at ig dot com dot br
20 years ago
Persistent connections either in socket or databases should be used only in servers where the limits are well defined. For example, the number of allowed connections in a database must be greater than the number of Apache's processes, or the connections will be refused by the database (this will surely occur if you use persistent connections). The same may occur with socket connections. This is up to the service configuration. In my opinion, persistent connections are useful only if you have total control over the one or more servers involved, like on a heavy loaded dedicated server for example, where the little gain in performance worth the use of such connections. Never use them in a shared server.
bimal dot das at maxartists dot com
17 years ago
Here is how to POST a form action to a SSL server's cgi and retrieve output with pfsockopen


= gethostbyaddr($_SERVER['REMOTE_ADDR']);

# working vars
$host = '';
$service_uri = '/cgi-bin/processACT';
$vars ='code=22&act=TEST';

# compose HTTP request header
$header = "Host: $host\r\n";
$header .= "User-Agent: PHP Script\r\n";
$header .= "Content-Type: application/x-www-form-urlencoded\r\n";
$header .= "Content-Length: ".strlen($vars)."\r\n";
$header .= "Connection: close\r\n\r\n";

$fp = pfsockopen("ssl://".$host, 443, $errno, $errstr);
if (!
$fp) {
"$errstr ($errno)<br/>\n";
} else {
fputs($fp, "POST $service_uri HTTP/1.1\r\n");
fputs($fp, $header.$vars);
fwrite($fp, $out);
while (!
feof($fp)) {
fgets($fp, 128);

ludvig dot ericson at gmail dot com
16 years ago
Confusion arises as to when PHP starts a new connection using all the
"persistent" versions of any function, and this depends entirely on how you
run your PHP.

In real CGI mode, that is, one process per script, persistent functions do the
exact same as their "temporary" equivalents. If you have a threaded Apache
MPM, this persistence will open a connection per thread, but not immediately.
Think of it as a single PHP instance for each thread.

If you run prefork, the MPM that forks the Apache server into several
accept()ing subprocesses, you'll have one PHP instance per process.

This isn't always true as I might've missed some gotchas, but in general, do
know that a persistent can only try to be persistent.

As for grey at greywyvern dot moc: A cronjob would be a lot better suited
for this, and have it periodically update the index rather than request ~200
pages each time somebody searches, at least from what you describe it as.
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