Using curl_multi_getcontent() to Retrieve Content from Multiple cURL Sessions in PHP

In PHP development, network requests to other servers are often needed, and the cURL extension provides powerful functions for such communication; among them, curl_multi_getcontent() retrieves the content of a cURL session.

The curl_multi_getcontent() function obtains the response data from handles created by curl_multi_init() after they have been executed with curl_multi_exec(). It simply requires the cURL handle resource as its argument.

Below is a complete example demonstrating how to initialize two cURL handles, add them to a multi‑handle, execute them concurrently, fetch each handle’s content with curl_multi_getcontent(), and finally clean up the resources.

// Initialize cURL sessions
$ch1 = curl_init('http://www.example.com/api1');
$ch2 = curl_init('http://www.example.com/api2');

// Create a multi‑handle
$mh = curl_multi_init();

// Add the two handles to the multi‑handle
curl_multi_add_handle($mh, $ch1);
curl_multi_add_handle($mh, $ch2);

// Execute the multi‑handle
do {
    $status = curl_multi_exec($mh, $active);
} while ($status === CURLM_CALL_MULTI_PERFORM || $active);

// Retrieve each session’s content
$contents = array();
foreach([$ch1, $ch2] as $ch) {
    $content = curl_multi_getcontent($ch);
    $contents[] = $content;
}

// Remove handles and close the multi‑handle
curl_multi_remove_handle($mh, $ch1);
curl_multi_remove_handle($mh, $ch2);
curl_multi_close($mh);

// Output the retrieved contents
var_dump($contents);

The example first creates two individual cURL sessions with curl_init(), adds them to a multi‑handle, runs them with curl_multi_exec(), then uses curl_multi_getcontent() to collect each response into an array before cleaning up with curl_multi_remove_handle() and curl_multi_close().

It is important to ensure that the multi‑handle execution has finished before calling curl_multi_getcontent(), otherwise the function may not return the expected data.

In summary, curl_multi_getcontent() is a useful function for obtaining the results of multiple concurrent cURL requests, simplifying the handling of parallel API calls in PHP backend development.