Greetings everyone!
Currently, I am utilizing long polling. Initially, I worked on Open Server (Windows) locale; however, once I uploaded the script to the hosting, it ceased working.
My approach involved an infinite loop while (true) with a sleep(2) delay. This methodology functioned correctly on the local machine but not on the web hosting platform.
Upon seeking assistance from hosting tech support, they noted that the issue may be due to the hosting running on Linux while Windows was used previously. Is this truly the root cause? If so, what options do I have to remedy this issue?
Moreover, included below is a code example:
$set_time_limit = 5;
register_shutdown_function("fatal_handler");
function fatal_handler()
{
global $new_count, $set_time_limit;
$error = error_get_last();
if ($error["message"] == "Maximum execution time of $set_time_limit seconds exceeded")
{
// header('HTTP/1.1 200 OK');
exit("OK");
}
else
{
print_r($error);
}
}
date_default_timezone_set("Asia/Aqtau");
set_time_limit($set_time_limit);
while (true)
{
sleep(2); // If sleep is removed, then everything works (after 5 seconds it displays OK)
}
What type of web server is being utilized for hosting?
What is the current max_execution_time that has been set?
May I ask why an eternal cycle is required? This type of code can often lead to issues with most hosting providers (especially if running it through a web server in multiple processes).
What is the server's response code, and is there a combination of nginx + apache? If so, what connection timeouts have been configured?
Additionally, after how long of a period will your hosting provider terminate processes? And what output can be found in errors_log?
While more questions could be asked to provide a thorough answer, it's essential to ask well-formulated questions to receive a valuable response.
Furthermore, it's not recommended to create daemons on virtual hosting since it can disrupt other users and result in restrictions to your site or account.
In the provided code example, the register_shutdown_function is used to define a callback function called "fatal_handler". This function is executed when the script is about to terminate due to a fatal error.
The purpose of the "fatal_handler" function is to check for a specific error message: "Maximum execution time of $set_time_limit seconds exceeded". If this error is detected, it means that the script has exceeded the maximum allowed execution time set by the $set_time_limit variable.
In that case, the script sends a response with the message "OK" and terminates. It seems that this code is designed to prevent the script from timing out if it runs for too long.
However, it's worth noting that using an infinite loop with sleep in a web hosting environment might not be the best approach for long polling. Long polling typically involves making an asynchronous request, keeping the connection open until there is new data available, and then receiving that data in the response.
Using an infinite loop with sleep may consume unnecessary server resources and can be less efficient compared to other technologies like WebSockets or Server-Sent Events that are specifically designed for real-time communication.
Here are more details about alternative approaches to long polling that you can consider:
1. WebSockets: WebSockets is a communication protocol that enables full-duplex, real-time communication between a client and a server. Unlike traditional HTTP requests, WebSockets allow bi-directional communication, meaning the server can push data to clients without the need for continuous requests. It provides a more efficient and real-time solution for long polling scenarios.
2. Server-Sent Events (SSE): SSE is another technology that enables servers to push data to clients over HTTP in a streaming fashion. It establishes a persistent connection between the client and the server, allowing the server to send events to the client whenever new data is available. SSE is well-suited for scenarios where the server needs to continuously send updates or notifications to the client.
3. AJAX Polling: AJAX polling is a simpler alternative to long polling. Instead of an infinite loop with sleep, the client periodically sends requests to the server to check for new data. The server responds immediately, either with the new data or a signal indicating no new data is available. While this method is less efficient than WebSockets or SSE, it can still be effective for scenarios with low update frequencies.
Each of these alternatives has its own advantages and considerations. Choosing the most appropriate option depends on your specific requirements, the capabilities of your hosting environment, and the level of real-time interactivity you need.