Analyze how php extension calls existing methods

In PHP development, extension is a useful tool that can provide programmers with special function expansions such as encryption, database storage, network communication, etc. to meet various needs. However, when using extensions, we often need to call existing methods to achieve the necessary functions. Therefore, this article will analyze how PHP extensions call existing methods.

1. Understand the extension definition

In the process of using extensions, we must first understand the definition and basic structure of extensions. Generally speaking, the extension definition includes the name of the module, the version number of the module, and the constants of the module. For calling existing methods, we need to check the external methods contained in the module and find the corresponding function names and parameters before calling them.

2. Loading extension

In order to call an existing method, you first need to load the extension. In PHP, extensions can be loaded through the php.ini configuration file or dynamically loaded using the dl() function in the code. Using dynamic loading, extensions can be loaded in real time in the code to avoid occupying system resources when they are not needed.

For example, to load the openssl extension, you can add the following content to the code:

if(!extension_loaded("openssl")){
    dl("php_openssl.dll");
}

3. View the function definition and parameters

After loading the extension, we You need to view the function definition and parameter list before calling it. In the installation package of the extension library, there is usually a corresponding API document or official manual, and you can view the detailed information of the extension function.

For example, in the openssl extension, to use the encryption function openssl_encrypt(), you can view the function definition and parameters in the official manual, for example:

string openssl_encrypt ( string $data , string $method , string $password [, int $options = 0 [, string $iv = "" [, string $tag = "" [, string $aad = "" ]]]] )

Among them, $data means to encrypt In plain text, $method represents the encryption algorithm, $password represents the encryption password, $options represents the encryption options, $iv represents the initialization vector, $tag represents the authentication tag, and $aad represents additional authentication data.

4. Call existing methods

By viewing the function definition and parameter list, we can use existing methods in the extension. In the specific implementation, we need to reference the extension library in the code, then call the existing method and pass the corresponding parameters. For example, use openssl_encrypt() method for encryption:

// 加载openssl扩展
if(!extension_loaded("openssl")){
    dl("php_openssl.dll");
}

// 要加密的明文
$data = "Hello, World!";

// 加密算法
$method = "aes-128-cbc";

// 加密密码
$password = "123456";

// 初始化向量
$iv = "1234567890123456";

// 加密
$ciphertext = openssl_encrypt($data, $method, $password, OPENSSL_RAW_DATA, $iv);

// 输出加密结果
echo base64_encode($ciphertext);

When calling existing methods, you need to pay attention to the type, value and order of parameters to avoid calling errors. At the same time, we can also implement specific functions through the methods provided by the extension library. For example, in the redis extension, you can use the redis_get() method to obtain the value in redis.

5. Summary

Through the above analysis, we can understand how the PHP extension calls existing methods. First, you need to understand the definition and basic structure of the extension library, then load the corresponding extension, check the function definition and parameter list, and finally call the existing methods in the extension library through code. In actual development, we can call different extensions according to needs and use existing methods as much as possible to improve the operating efficiency and stability of the program.

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