The PHP programmer who was tricked into crying by swoole

This article mainly records the process of learning swoole, the pitfalls that have been filled, and how powerful swoole is!

First, let me talk about my understanding of swoole: a C program dressed in PHP. Many PHPer friends saw the powerful functions provided by swoole and the admiration of the outside world, so they eagerly installed, debugged its demo, wrote new functions, and then rushed to tell each other excitedly. After a few days, when you continue to use swoole according to your own understanding, you find that the code does not run as you expected, and then you start to curse, what a crap thing, the code is basically the same as the demo, why doesn't it work? What nonsense work, tasks, shared memory, ipcs, asynchronous, all kinds of problems emerged, and then I quickly checked the official documents and found that there was no mention of these in the documents. It just briefly introduced how to use it. At this time, I almost lost hope in swoole. .

Several problems encountered:

1: Regarding why the global variable (global) commonly used in phper cannot be used in the onRequest function.

Because swoole is multi-threaded programming, global cannot be shared between multiple processes. Example

<ol>
<li><span><span>global $i = </span><span>0</span><span>; </span></span></li>
<li><span> </span></li>
<li><span>function onRequest() { </span></li>
<li><span> </span></li>
<li><span>    echo $i++; </span></li>
<li><span> </span></li>
<li><span>} </span></li>
</ol>

If you write the above program in swoole, it will not output an increasing number every time it is accessed. If you want to achieve the expected effect, you need to use the related functions of swoole_table.

2: What is asynchronous and what is callback

For phper, the understanding of asynchronous and callback is probably ajax. When I saw the explanation of asynchrony and callbacks in swoole, it seemed very simple, so I rashly used swoole without any experience in multi-threaded editing. As a result, I was tricked into secretly coding for several nights to fill my own pitfalls.

3: Why is the data received by onReceive so large?

The server can receive multiple requests sent by the client at once. It’s not that the client sends it once and the server receives it once

4: Homemade httpserve

Write an http server, then access this home-made server through the browser, refresh the browser, why does the server receive Two requests? This problem probably troubles many friends who are using swoole to write httpserver for the first time. Because the browser will send one more favicon.ico request.

Reason

The reason for this situation is actually very simple. Most phpers only know php. Their main purpose is to make web and write business logic. Few people understand the development of server programs. Once, a friend used swoole to write a simple server and a client. He came to me and asked me why I couldn’t receive data even though I started it. I briefly looked at the code and found that all connections were successful. Both ends were successful. The onReceive callback was set up, and the code was fine. At the end, I discovered that both the server and the client had set callback functions for receiving messages, but neither end sent a message to the other, and the two ends were in a stalemate. Then swoole officials did not give any explanation on this common sense issue, they just talked about how to set up callbacks, how to send messages, how to do this, and how to do that. For students who have server-side development experience, they will definitely not encounter this problem, and the swoole document does not need to specify the need to do this, because it is common sense. But for phper, it is very important to indicate this point, because as mentioned above, phper does not have this knowledge. Only programmers with server-side development experience can. Swoole’s features: network communication framework, asynchronous, multi-threading. These features are exactly the imperfect functions of PHP (although the official provides many basic functions to realize these functions, but there is a lack of Chinese documentation, and few people use PHP to implement these functions). Ordinary PHP does not have the basic understanding of these features. You know, so if you use swoole rashly, you will inevitably encounter some common sense problems that cannot be found on the swoole official website.

Skills that must be mastered to use swoole

Multi-threaded programming
2. Inter-process communication

Cognition of network protocol TCP/UDP
Basic skills of PHP
Personal experience of learning swoole

A long time ago, I was also a programmer who only knew PHP. Then I needed to use httpsqs by chance. After using it for a while, I found that I had some unique needs, so I started to look at the source code. This is really hard to see, and it is shocking at first glance. httpsqs is just a simple packaging, and inside is a Tokyo Cabinet database. In my impression, the packaged code is only more than a hundred lines. The main idea is to use libevent in C language to make an http server to receive requests to read and write the Tokyo Cabinet database. At that time, there were indeed many programs based on this idea. Later, I suddenly thought that since C language can use the libevent function, then PHP can definitely use libevent to monitor the network, read and write the database to provide queueservice after receiving the request. Later, after checking the official PHP documentation, I found that PHP does provide a complete system of functions to complete these functions, and even a full set of multi-threaded functions are provided. However, there are too few Chinese documents, and mature codes are rarely found online. Under forced circumstances, I learned the basic principles of linux-C multi-thread development, the common methods of inter-process communication, and also used it to make some simple demos. The only feeling is that writing a simple function is really complicated to design. Just when I was about to give up, swoole appeared. The functions provided by swoole are exactly the functions missing in php, which is simply great. As a network communication framework, swoole only requires a few simple lines of settings to set up a server. From now on, we will continue to improve the business code. I learned in the libevent exchange group that swoole's design is not the best framework design in cc++, but its highlight is that the basic functions are encapsulated in C, and the business functions are written in PHP, the best language in the world. Since then, Swoole's journey of filling holes has begun.

Summary

swoole is not a simple PHP framework, just like the first sentence of the swoole official homepage "Redefine PHP", never use the old PHP thinking to write swoole code! swoole reactivates PHP, and php makes swoole!

The above introduces the PHP programmers who were tricked by swoole, including the content. I hope it will be helpful to friends who are interested in PHP tutorials.