Introduction to developing PHP extensions

PHP is a widely used open source scripting language that provides web developers with many feature-rich development frameworks and libraries. However, there are situations where using PHP's built-in functions and language features may not satisfy all development needs. In this case, developing PHP extensions can be a useful solution.

This article will provide you with basic concepts about developing PHP extensions, including how to write, compile and install PHP extensions, and how to use them.

1. What is a PHP extension?

PHP extension is a dynamic link library that can be written in C language. By writing PHP extensions, you can extend the PHP parser, add custom functions and classes, and change PHP's behavior. This makes PHP extensions very useful in high-performance, high-throughput web applications and toolboxes for extending PHP.

2. Writing PHP extensions

Developing PHP extensions is an advanced topic and requires knowledge and experience in C programming. When writing a PHP extension, you need to use PHP's C API to interact with the PHP parser and use a dynamic link library to create reusable binaries.

In order to create a simple PHP extension, we can follow the following steps:

1. Create a C source file and include the PHP header file

#include <php.h>

2. Define a Methods that get input parameters and add your custom logic in them

ZEND_FUNCTION(my_function){
    char *input_str;
    int input_len;
    if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s", &input_str, &input_len) == FAILURE) {
        RETURN_NULL();
    }
    // 添加自定义逻辑
    RETURN_STRINGL(input_str, input_len, 1);
}

3. Define parameters and return values ​​for PHP methods

ZEND_BEGIN_ARG_INFO(arginfo_my_function, 0)
    ZEND_ARG_INFO(0, input_str)
ZEND_END_ARG_INFO()

const zend_function_entry my_functions[] = {
    ZEND_FE(my_function, arginfo_my_function)
    { NULL, NULL, NULL }
};

4. Define global information for PHP extensions

zend_module_entry my_module_entry = {
    STANDARD_MODULE_HEADER,
    "my_extension",
    my_functions,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    "1.0",
    STANDARD_MODULE_PROPERTIES
};

5. Write the PHP extension initialization function to register the extension

ZEND_GET_MODULE(my_extension)

PHP_MINIT_FUNCTION(my_extension){
    return SUCCESS;
}

3. Compile and install the PHP extension

Through the above steps, we have created a PHP extension. Next, we need to compile it into a dynamic link library and install it into our PHP environment. This can be done by following the steps:

1. Generate the Makefile by running the following command in the PHP extension source code directory

/php-src-path$: phpize

2. Build the extension by running the following command

/php-src-path$: ./configure --enable-my_extension
/php-src-path$: make

3. Copy the generated dynamic link library to the PHP extension directory

/php-src-path$: sudo make install

4. Modify the php.ini file to enable the PHP extension

extension=my_extension.so

Now, we have successfully compiled and installed the PHP extension into in our PHP environment.

4. Using PHP extension

Using PHP extension is very simple. Once you have installed the PHP extension into your PHP environment, you can use the extension just like the built-in functions. For example, in our example, we can use the following PHP code to call the my_function function:

$input_str = "hello world";
$output_str = my_function($input_str);
echo $output_str; // 输出 hello world

Summary

This article introduced the basic concepts of developing PHP extensions. By writing, compiling and installing your own PHP extensions, web developers can easily extend the functionality of PHP, add custom functions and classes, and improve the performance of web applications. Additionally, extension development can serve as a great way to learn and gain insight into the inner workings of PHP.

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