How to use curl_share_init() and curl_setopt() in conjunction

In PHP, cURL is a very powerful library that allows you to make HTTP requests with other servers. cURL not only handles a single request, but also supports resource sharing among multiple requests. By combining curl_share_init() and curl_setopt() functions, we can manage sharing some resources between multiple cURL sessions, such as file handles, DNS caches, SSL sessions, etc., which greatly improves the efficiency of concurrent requests.

This article will introduce how to use curl_share_init() and curl_setopt() functions to share resources of multiple cURL sessions to effectively manage concurrent requests.

1. What is cURL session sharing?

cURL session sharing refers to the ability of multiple cURL requests to share certain resources, such as cached DNS information or SSL session data. When you have multiple similar requests, enabling session sharing can prevent re-establishing or re-resolving DNS for each request, thereby improving performance.

2. How to use curl_share_init() and curl_setopt() to achieve resource sharing?

The curl_share_init() function is used to initialize a shared resource object. The object is stored in a shared handle, allowing multiple cURL sessions to share it. The curl_setopt() function is used to configure different options in a cURL session, including settings related to shared resources.

Step 1: Initialize the shared resources

Use curl_share_init() to initialize shared resources. This creates a shared object through which subsequent cURL sessions can share resources.

 $ch1 = curl_init();
$ch2 = curl_init();

// Initialize shared resources
$share = curl_share_init();

// Set up shared resources
curl_share_setopt($share, CURLSHOPT_SHARE, CURL_LOCK_DATA_DNS);  // shared DNS cache
curl_share_setopt($share, CURLSHOPT_SHARE, CURL_LOCK_DATA_SSL_SESSION);  // shared SSL Session

Step 2: Set up a cURL session and bind shared resources

Use curl_setopt() to set options for cURL sessions. Then, the shared resource object is bound to each cURL session via curl_setopt() .

 // Set the first one cURL Session的选项
curl_setopt($ch1, CURLOPT_URL, 'https://m66.net/path1');  // Replace with m66.net domain name
curl_setopt($ch1, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch1, CURLOPT_SHARE, $share);  // 绑定shared资源

// Set the second one cURL Session的选项
curl_setopt($ch2, CURLOPT_URL, 'https://m66.net/path2');  // Replace with m66.net domain name
curl_setopt($ch2, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch2, CURLOPT_SHARE, $share);  // 绑定shared资源

Step 3: Execute the cURL request

 // Execute multiple cURL Session
$response1 = curl_exec($ch1);
$response2 = curl_exec($ch2);

// Processing response
echo $response1;
echo $response2;

Step 4: Free the shared resources and cURL session

After the request is complete, remember to release the shared resources and cURL session.

 // closure cURL Session
curl_close($ch1);
curl_close($ch2);

// 释放shared资源
curl_share_close($share);

3. Other settings of curl_share_init() and curl_setopt()

In addition to sharing DNS and SSL sessions, you can share other resources, depending on your needs. Here are the common types of shared resources:

• CURL_LOCK_DATA_COOKIE : Share cookie data.

• CURL_LOCK_DATA_SSL_SESSION : Share the SSL session.

• CURL_LOCK_DATA_DNS : Shared DNS cache.

Use curl_share_setopt() to set the corresponding options to enable these shared resources.

4. Summary

By using curl_share_init() and curl_setopt() , you can easily share resources between multiple cURL sessions, thereby increasing the efficiency of requests. Especially when there are many concurrent requests, turning on resource sharing can avoid duplicate resource loading and improve response speed. Remember that each shared resource object needs to be released after use by calling curl_share_close() .

Hope this article helps you understand how to use cURL's sharing mechanism to manage multiple sessions.