How do I ensure that the connection is closed properly after curl_close when sending a POST request?

In PHP, cURL is a very powerful tool that allows you to send requests and receive responses via URLs. Through cURL, you can easily send HTTP requests such as GET, POST, PUT, DELETE, etc.

 $ch = curl_init();  // initialization cURL Session
curl_setopt($ch, CURLOPT_URL, "https://gitbox.net/your-api-endpoint");  // Set up a request URL
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);  // Set the return response as a string

// in the case of POST ask，set up POST data
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query(['key' => 'value']));

$response = curl_exec($ch);  // 执行ask并获取response

curl_close($ch);  // closure cURL Session

In the above code, we use curl_exec to execute the request, and call curl_close after executing the request to close the cURL session.

2. Make sure that the POST request has been sent completely

Before calling curl_close , PHP will wait for the request response after calling curl_exec . Therefore, as long as curl_exec executes successfully, the POST requested data has been sent. However, it is important to ensure that the request is sent completely before closing the connection, especially when a long request is executed.

To ensure that the POST request data is sent completely and the connection is closed normally, we can use curl_getinfo to check the status code or other response information of the response.

 $ch = curl_init();
curl_setopt($ch, CURLOPT_URL, "https://gitbox.net/your-api-endpoint");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query(['key' => 'value']));

$response = curl_exec($ch);

// 获取ask的详细信息
$info = curl_getinfo($ch);
if ($info['http_code'] == 200) {
    // Processing response
    echo "POST ask已成功发送，response：$response";
} else {
    echo "ask失败，HTTP Status code：" . $info['http_code'];
}

curl_close($ch);

The http_code information obtained through curl_getinfo can help us determine whether the request was successfully sent. If the HTTP status code is 200 (indicating that the request is successful), it can be determined that the POST request has been sent completely.

3. Handle timeouts and errors

Sometimes when sending a POST request, you may experience connection timeout or other network problems. In this case, it is very important to set the timeout parameter using curl_setopt .

 $ch = curl_init();
curl_setopt($ch, CURLOPT_URL, "https://gitbox.net/your-api-endpoint");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query(['key' => 'value']));
curl_setopt($ch, CURLOPT_TIMEOUT, 30);  // set up超时为 30 Second

$response = curl_exec($ch);

// Handling errors
if (curl_errno($ch)) {
    echo "cURL mistake: " . curl_error($ch);
} else {
    echo "response: $response";
}

curl_close($ch);

Setting CURLOPT_TIMEOUT ensures that the request is completed within a reasonable time and will immediately stop the request if the timeout.

4. Why do you need to close the connection?

After each cURL request is over, it is very important to call curl_close . It can free cURL-related resources and close HTTP connections. If curl_close is not called, it may lead to memory leaks or other resource waste.

 curl_close($ch);  // 必须closure连接以释放资源

In long-running applications, not closing the connection can cause excessive consumption of system resources, especially when you send a large number of requests. Therefore, every time you use cURL, make sure to call curl_close to close the connection.