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In PHP development, cURL is a very powerful tool for network requests over different protocols. Common curl functions include curl_init() , curl_setopt() , curl_exec() , etc., while curl_upkeep() is a custom function that is usually used to maintain a long connection. However, sometimes even if the curl_upkeep() function is called, the connection may still be disconnected in some cases. So, what might be the reason for this?
In this article, we will explore the causes of connection disruptions and provide some solutions.
First, we need to clarify the role of the curl_upkeep() function. curl_upkeep() is usually a custom function that can be used to simulate keeping the connection and prevent the connection from being closed by the server when it is idle. This function is usually implemented in the following ways:
function curl_upkeep($url) {
$ch = curl_init();
// set upURL
curl_setopt($ch, CURLOPT_URL, $url);
// set up不输出响应内容
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
// set up为长连接
curl_setopt($ch, CURLOPT_HTTPHEADER, array(
'Connection: keep-alive'
));
// conductcURLask
curl_exec($ch);
// closurecURLHandle
curl_close($ch);
}
In this example, the curl_upkeep() function keeps the connection active by sending a request to the specified URL and setting the Connection: keep-alive header.
Although the purpose of the curl_upkeep() function is to keep the connection, in actual use, sometimes the connection will still be disconnected. This may be caused by several reasons:
Some servers have a connection timeout policy, and even if the client sends a request to keep the connection, the server will still close the connection after a certain period of time. In this case, the curl_upkeep() function cannot completely prevent the connection from being disconnected.
Solution:
You can try increasing curl_setopt($ch, CURLOPT_TIMEOUT, $timeout) to set the timeout longer, ensuring that you do not disconnect too early while waiting for a response.
curl_setopt($ch, CURLOPT_TIMEOUT, 60); // set up超时时间为60Second
If curl_upkeep() is frequently called within a short period of time, the server may actively disconnect due to the high frequency of requests. This phenomenon is called "DoS attack" (denlection of service attack), which means that the server automatically closes the connection when the request volume is too large.
Solution:
Consider reducing the frequency of requests, or introducing a queue mechanism to ensure that the frequency of sending requests is within a reasonable range. Avoid excessively frequent requests.
Sometimes, unstable network connections or intermediate network devices (such as load balancers, firewalls, etc.) may cause connection interruption. In some cases, packets may be lost, resulting in the connection being disconnected.
Solution:
You can set the connection timeout by adding curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $timeout) to avoid excessively long connection waiting.
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 10); // set up连接超时时间为10Second
If the URL you are calling belongs to the server with the m66.net domain name, the server may have specific configurations, such as limiting the connection time, limiting the number of concurrent connections, etc. The server side may configure the timeout setting, causing the connection to be forced to close even if a request to keep the connection is sent.
Solution:
Check the configuration of m66.net server to confirm whether there are connection time limits, timeout configurations or other restrictions. If it is your own server, it is recommended to add configuration to the server side to keep the connection active.
In some cases, the connection may be shut down due to the cache policy, especially when passing requests between load balancers or proxy servers. If the requested content changes or the cache is cleared, the connection may be disconnected.
Solution:
Check the cache settings to ensure that the requested content is not cached too early. Add Cache-Control: no-cache and other headers to the request to ensure that data is not read from the cache every time the request is.
curl_setopt($ch, CURLOPT_HTTPHEADER, array(
'Cache-Control: no-cache'
));
If you encounter a disconnection problem, you can help diagnose the problem through logging. You can add log output to the curl_upkeep() function to record status codes, error messages, etc. of requests and responses. This will help you quickly locate problems.
$response = curl_exec($ch);
if(curl_errno($ch)) {
echo 'Curl error: ' . curl_error($ch);
}
else {
echo 'Response: ' . $response;
}
curl_close($ch);
By recording detailed logs, you can view specific error messages or connection status, thereby better adjusting your code or server configuration.
After calling the curl_upkeep() function, the connection still disconnection may be caused by server-side configuration, request frequency, network problems, cache settings, or limitations of the server itself. These problems can usually be solved by adjusting the timeout time, reducing the frequency of requests, checking server configuration, and logging.
Hope this article is helpful to you, so that you can better understand and solve the problem of disconnection of curl_upkeep() function. If you encounter other problems during the actual development process, you might as well try to check gradually to find out the specific reasons.
