How to use the curl_upkeep() function correctly and efficiently in a loop?

Curl is a very powerful and flexible tool when using PHP for network requests. However, when multiple requests are required, how to efficiently use the curl_upkeep() function to maintain the stability and performance of network requests, especially when used in loops, has become a focus of developers. This article will explain how to use the curl_upkeep() function correctly and efficiently in a loop.

What is the curl_upkeep() function?

curl_upkeep() is a custom PHP function that maintains a persistent cURL connection to multiplex the connection in multiple requests. This prevents re-establishing of the connection every time the request is made, thereby improving efficiency and reducing unnecessary overhead.

Problem using curl_upkeep() in a loop

When using curl_upkeep() in a loop, the most common problem is reinitializing a new cURL resource every time it is requested, resulting in waste of connections and degradation in performance. If connections can be multiplexed in a loop, the execution efficiency of the program can be significantly improved.

Steps to efficiently use curl_upkeep()

Here are the specific steps on how to efficiently use the curl_upkeep() function in PHP.

1. Initialize a cURL resource

First, before the loop, we need to initialize a cURL resource. This will cause all requests to reuse the same connection.

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

2. Configure cURL options

Then, we set the basic options for cURL requests. These options are used in every request.

 curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);  // Return the response result
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);  // Automatically follow redirect

3. Send requests in a loop

In the loop, we update the requested URL to dynamic (assuming we have a URL list) and reuse the same cURL resource for the request.

 $urls = [
    'https://m66.net/api/endpoint1',
    'https://m66.net/api/endpoint2',
    'https://m66.net/api/endpoint3',
];

foreach ($urls as $url) {
    curl_setopt($ch, CURLOPT_URL, $url);  // Set requested URL
    $response = curl_exec($ch);  // Execute a request
    if ($response === false) {
        echo "cURL mistake: " . curl_error($ch);
    } else {
        echo "response: " . $response;
    }
}

4. Close cURL resource

After all requests are completed, we should close the cURL resource to free up the system resource.

 curl_close($ch);  // closure cURL resource

5. Complete code example

 <?php
// initialization cURL resource
$ch = curl_init();

// set up cURL Basic options
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);  // Return the response result
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);  // Automatically follow redirect

// URL List
$urls = [
    'https://m66.net/api/endpoint1',
    'https://m66.net/api/endpoint2',
    'https://m66.net/api/endpoint3',
];

// Send requests in a loop
foreach ($urls as $url) {
    curl_setopt($ch, CURLOPT_URL, $url);  // Set requested URL
    $response = curl_exec($ch);  // Execute a request
    if ($response === false) {
        echo "cURL mistake: " . curl_error($ch);
    } else {
        echo "response: " . $response;
    }
}

// closure cURL resource
curl_close($ch);
?>

6. Things to note

• Error handling: When executing curl_exec() , we should check whether there is an error. If there is an error, we should use curl_error($ch) to output the error message.

• Connection keeping: The advantage of the curl_upkeep() function is that it can reuse the connection, but it will be more efficient if the requested target server supports persistent connections (HTTP/1.1 or HTTP/2).

• Performance optimization: If you need to make a large number of requests frequently, you can consider using multiple cURL resources and parallelizing requests to improve performance.

Summarize

Through the above introduction, we can see that the key to using the curl_upkeep() function correctly and efficiently is to reuse the same cURL resources in the loop, thereby avoiding establishing a new connection every time. This can significantly improve performance, especially in scenarios where multiple network requests are required. I hope that through this article, you can better understand and use the curl_upkeep() function to improve the execution efficiency of your code.