Cooperation skills between curl_upkeep() and curl_setopt()

In PHP, cURL is a very powerful library for sending requests between servers and capable of efficiently handling HTTP requests and responses. When it comes to the need to maintain long connections, curl_setopt() and some other configuration options can greatly improve connection stability and performance.

This article will discuss how to configure cURL through curl_setopt() and use curl_upkeep() correctly to improve stability when maintaining long connections.

1. Understand curl_setopt() and curl_upkeep()

1. Introduction to curl_setopt()

curl_setopt() is an important function in the PHP cURL function library, and its function is to set various options for cURL sessions. By setting these options, you can control various aspects of HTTP requests, such as request method, timeout time, request header, etc.

Common curl_setopt() configuration options include:

• CURLOPT_URL : Sets the requested URL.

• CURLOPT_RETURNTRANSFER : Returns the response result as a string, rather than output directly.

• CURLOPT_TIMEOUT : Sets the request timeout time.

• CURLOPT_HTTPHEADER : Sets the HTTP request header.

2. Introduction to curl_upkeep()

curl_upkeep() is a helper function for cURL when handling long connections and is usually used to maintain the stability of persistent connections. This function ensures that the connection is not closed when it is not used for a period of time and is suitable for scenarios where requests are frequently sent but do not want to establish connections frequently.

2. Steps to use curl_setopt() with curl_upkeep()

1. Initialize the cURL session

First, you need to initialize a cURL session and create a session handle via curl_init() .

 $ch = curl_init();

2. Set the requested URL and other configurations

Next, you can use curl_setopt() to set necessary options such as URL, request method, connection timeout, etc.

 curl_setopt($ch, CURLOPT_URL, "https://m66.net/someapi");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_TIMEOUT, 30);
curl_setopt($ch, CURLOPT_HTTPHEADER, array(
    "Authorization: Bearer YOUR_ACCESS_TOKEN"
));

3. Use curl_upkeep() in conjunction with

To improve the stability of long connections, curl_upkeep() can be used in conjunction with it. This function ensures the stability of the connection during the session, avoiding the connection timeout or interruption.

 curl_upkeep($ch);

This will help cURL maintain a stable connection, ensuring that multiple requests are not frequently disconnected and reconnected.

4. Execute the request and get the response

Execute the request through curl_exec() and get the returned response result.

 $response = curl_exec($ch);
if(curl_errno($ch)) {
    echo 'Error:' . curl_error($ch);
}

5. Close the cURL session

After all operations are completed, remember to close the cURL session.

 curl_close($ch);

3. Practical skills to improve long connection stability

To maximize the stability and performance of cURL, you can refer to the following tips:

1. Set a longer timeout

For long connections, appropriately increasing the timeout time can effectively prevent the connection from closing prematurely.

 curl_setopt($ch, CURLOPT_TIMEOUT, 60);  // Increase timeout

2. Use Keep-Alive header

The HTTP Keep-Alive header tells the server to maintain a persistent connection, avoiding re-establishing the connection every time you request.

 curl_setopt($ch, CURLOPT_HTTPHEADER, array(
    "Connection: keep-alive"
));

3. Adjust CURLOPT_MAXREDIRS

When redirects are encountered, you can use the CURLOPT_MAXREDIRS option to control the maximum number of redirects, thereby avoiding the dead loop of infinite redirects.

 curl_setopt($ch, CURLOPT_MAXREDIRS, 5);

4. Send heartbeat packets regularly

Send requests to the server regularly to maintain the connection active. The heartbeat mechanism can be implemented using a timed task or a short request interval.

 // Example：Every5Send a request once in minutes to keep the connection active
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, "https://m66.net/heartbeat");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$response = curl_exec($ch);
curl_close($ch);