Use curl_upkeep() to extend the connection life of HTTP/2

M66 2025-05-27

In modern web development, the HTTP/2 protocol has gradually become the mainstream due to its efficient multiplexing characteristics. However, in order to make full use of the advantages of HTTP/2, connection management and maintenance are particularly important. As a tool used to extend the HTTP/2 connection life cycle, the curl_upkeep() function can effectively reduce frequent connection establishment and destruction and further improve request efficiency. This article will explore in-depth how to optimize HTTP/2 connections using curl_upkeep() function.

What are HTTP/2 and its advantages?

HTTP/2 is the second major version of the HTTP protocol. Compared with HTTP/1.1, it has many optimizations, mainly including:

Multiplexing : HTTP/2 can send multiple requests and responses in parallel on a single connection, avoiding head-of-line blocking in HTTP/1.1.
Header Compression : HTTP/2 uses HPACK compression technology to compress request and response headers, reducing the burden of network transmission.
Server Push : Allows the server to actively send resources to the client before the client requests.

These features allow HTTP/2 to significantly improve page loading speed and reduce latency.

The function of curl_upkeep() function

curl_upkeep() is a function in the PHP extension library. It reduces the performance overhead caused by frequent connection establishment and closing by keeping HTTP/2 connections active. By extending the life cycle of the connection, curl_upkeep() can effectively improve the efficiency of requests, especially when a large number of requests are required.

In the HTTP/2 protocol, it is important to maintain a persistent connection because each connection requires additional time and compute resources. curl_upkeep() enables connections to survive, avoiding frequent re-establishment of connections, thereby reducing latency and resource consumption.

How to use curl_upkeep() function in PHP

To optimize HTTP/2 requests using the curl_upkeep() function in PHP, we first need to ensure that the PHP environment supports HTTP/2 and curl extensions. Next, we will explain how to implement this function through code.

Install and configure curl extensions

Make sure that curl extension is enabled in your PHP installation. If not enabled, you can install it with the following command:

 sudo apt-get install php-curl

Enable curl extension in PHP configuration file php.ini :

 extension=curl.so

Writing PHP scripts using curl_upkeep()

Here is a simple PHP example showing how to use the curl_upkeep() function to extend the life cycle of an HTTP/2 connection.

 <?php

// initialization cURL Session
$ch = curl_init();

// set up URL，Make sure to use HTTPS protocol
curl_setopt($ch, CURLOPT_URL, "https://m66.net/api/data");

// Enable HTTP/2
curl_setopt($ch, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_2_0);

// set up超时时间，Avoid long-term request hang
curl_setopt($ch, CURLOPT_TIMEOUT, 30);

// Enable持久连接，Reduce the time overhead of frequent connection establishment
curl_setopt($ch, CURLOPT_FORBID_REUSE, false); // Allow connection multiplexing

// Open keep-alive Mechanism to extend connection life cycle
curl_setopt($ch, CURLOPT_TCP_KEEPALIVE, true);
curl_setopt($ch, CURLOPT_TCP_KEEPIDLE, 60); // Stay idle 60 Second
curl_setopt($ch, CURLOPT_TCP_KEEPINTVL, 30); // Every 30 Second发送一次保持活动包

// Send a request
$response = curl_exec($ch);

// Check for errors
if(curl_errno($ch)) {
    echo 'Curl error: ' . curl_error($ch);
} else {
    echo "Response: " . $response;
}

// closure cURL Session
curl_close($ch);

?>

Key parameter description:

CURL_HTTP_VERSION_2_0 : Enable the HTTP/2 protocol.
CURL_FORBID_REUSE : Allows multiplexing of connections to avoid creating new connections every time you request.
CURL_TCP_KEEPALIVE : Enable keep-alive function to keep the connection active.
CURL_TCP_KEEPIDLE : Sets the timeout time (unit: seconds) for the connection to be idle, that is, if no data is sent within this time, the connection will be maintained.
CURL_TCP_KEEPINTVL : Sets the time between sending keep-alive packets.

Benefits of Extended Connection

By configuring the retention policy of HTTP/2 connections reasonably, the curl_upkeep() function can help improve request efficiency, especially when frequent access to the same host, which can reduce the time overhead of establishing a new connection. In this way, you can not only reduce network latency, but also save server computing resources and improve user experience.

in conclusion

When using the HTTP/2 protocol, extending the connection life cycle through the curl_upkeep() function can effectively reduce the frequency of connection establishment and closing, thereby improving request efficiency. PHP's curl extension provides flexible configuration options, allowing developers to fine-tune connection management policies and take advantage of the performance benefits of HTTP/2.

Hope the introduction in this article can help you better understand and use the curl_upkeep() function to improve HTTP/2 performance in PHP applications.

curl_upkeep