PHP socket_set_timeout Function
last modified April 4, 2025
The PHP socket_set_timeout function sets timeout values for socket
operations. It's essential for network programming to prevent hanging.
Basic Definition
socket_set_timeout configures timeout values for socket streams.
It affects operations like reading, writing, and connecting.
Syntax: socket_set_timeout(resource $socket, int $seconds, int $microseconds = 0): bool.
Returns true on success, false on failure. Works with stream sockets.
Setting Basic Socket Timeout
This example demonstrates setting a simple timeout for socket operations.
<?php
declare(strict_types=1);
$socket = fsockopen("example.com", 80);
if ($socket === false) {
die("Connection failed");
}
// Set 5 second timeout
socket_set_timeout($socket, 5);
// Perform socket operations...
fclose($socket);
This sets a 5-second timeout for all operations on the socket. After this period, operations will timeout if not completed. Prevents indefinite blocking.
Precise Timeout with Microseconds
This shows how to set a timeout with microsecond precision for exact timing.
<?php
declare(strict_types=1);
$socket = fsockopen("example.com", 80);
if ($socket === false) {
die("Connection failed");
}
// Set 2.5 second timeout (2 seconds + 500000 microseconds)
socket_set_timeout($socket, 2, 500000);
// Read operation with precise timeout
$data = fread($socket, 1024);
fclose($socket);
This sets a 2.5 second timeout by combining seconds and microseconds. Useful when you need more precise control over timeout durations.
Checking for Timeout Condition
This example demonstrates how to check if a timeout occurred during operations.
<?php
declare(strict_types=1);
$socket = fsockopen("example.com", 80);
if ($socket === false) {
die("Connection failed");
}
socket_set_timeout($socket, 3);
$data = fread($socket, 1024);
$info = stream_get_meta_data($socket);
if ($info['timed_out']) {
echo "Socket operation timed out";
} else {
echo "Operation completed successfully";
}
fclose($socket);
After socket operations, we check the stream metadata for timeout status. This helps identify if operations failed due to timeout conditions.
Different Timeouts for Read/Write
This shows how to set different timeout values for read and write operations.
<?php
declare(strict_types=1);
$socket = fsockopen("example.com", 80);
if ($socket === false) {
die("Connection failed");
}
// Set read timeout (5 seconds)
socket_set_timeout($socket, 5);
// Perform read operations...
// Set write timeout (2 seconds)
socket_set_timeout($socket, 2);
// Perform write operations...
fclose($socket);
Different operations may need different timeout values. This example shows how to adjust timeouts between read and write operations.
Handling Slow Connections
This demonstrates using timeouts to handle slow or unreliable connections.
<?php
declare(strict_types=1);
function fetchWithRetry($host, $port, $retries = 3) {
$timeout = 2; // Start with 2 second timeout
for ($i = 0; $i < $retries; $i++) {
$socket = fsockopen($host, $port);
if ($socket === false) continue;
socket_set_timeout($socket, $timeout);
$data = fread($socket, 1024);
$info = stream_get_meta_data($socket);
if (!$info['timed_out']) {
fclose($socket);
return $data;
}
fclose($socket);
$timeout *= 2; // Double timeout for next retry
}
return false;
}
$data = fetchWithRetry("example.com", 80);
This implements a retry mechanism with increasing timeouts. Useful for handling temporary network issues or slow connections.
Best Practices
- Reasonable Timeouts: Set appropriate values for your use case
- Error Handling: Always check for timeout conditions
- Resource Cleanup: Close sockets properly after use
- Context Awareness: Adjust timeouts based on network conditions
Source
PHP socket_set_timeout Documentation
This tutorial covered the PHP socket_set_timeout function with practical
examples for network programming and timeout management.