PHP implements open source Redis driver

Redis is an open source in-memory data structure storage system that is usually used for caching, message queues, and real-time data analysis. In modern applications and Internet systems, Redis has become an indispensable component and is widely used.

As a PHP developer, how to use Redis and get the most out of it? A good starting point is to use the Redis driver and integrate it into your PHP application. This article explores the process of implementing an open source Redis driver using PHP to help developers better understand its principles and uses.

Operations supported by the Redis driver

The Redis driver supports a variety of operations, including strings, lists, hashes, sets, and ordered sets, etc. The following are some common operations:

String operations: used to set and get string values, modify string values, and perform operations on strings (such as appending certain characters before or after the string).

List operations: used to add, delete and get list elements, and support blocking operations to block the client when there are no elements in the list.

Hash operation: used to set, get and delete fields in the hash table, similar to an associative array.

Set operations: used to add, delete and obtain elements in the set, supporting operations such as set intersection, union and difference.

Ordered set operation: similar to a set, but each element has a score to support sorting of elements.

PHP extension

The way to implement the Redis driver using PHP is to use a PHP extension. In other words, we need to write a C language extension that converts the Redis protocol into a format that PHP can recognize, and passes the request executed by PHP to the Redis server. These extensions allow PHP applications to communicate with Redis through library function calls.

To write a PHP extension for Redis, you need to know some basic knowledge of the C language and the internal principles of PHP. In addition, you need to use APIs such as Zend API and Redis C API provided by PHP. These APIs are libraries of functions for building PHP extensions. Ultimately, we will compile the extension into a dynamic link library so that PHP applications can dynamically load it and use its functionality.

Steps to implement Redis driver in PHP

Next, we will introduce the steps to write Redis driver using PHP:

1. Install Redis server and PHP extension

First, you need to install the Redis server and PHP extension. It can be installed on Ubuntu with the following command:

sudo apt-get install redis-server php-redis

2. Write a C language extension

C Language extensions are the bridge between PHP and Redis servers. We need to use the API provided by PHP to convert the call into a format that Redis can understand. The following example shows code that inserts a string value into Redis:

PHP_FUNCTION(redis_set) {

char *key, *value;
zval *redis_obj;

if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "oss", &redis_obj, &key, &value) == FAILURE) {
    RETURN_NULL();
} 

redisContext *redis = redis_obj->redis;
redisReply *reply = redisCommand(redis, "SET %s %s", key, value);

RETURN_BOOL(reply->type == REDIS_REPLY_STATUS);

}

This code parses the parameters, including the Redis object used , keys and values ​​and send them to the Redis server. After the response is returned by the Redis server, the type of the response is checked and the result is returned accordingly.

3. Define PHP extension

PHP extension is where C language extensions are bound to PHP functions and constants. The following example shows how to bind the redis_set function into the Redis class in PHP:

PHP_METHOD(Redis, set) {

char *key, *value;
int key_len, val_len;

if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "ss", &key, &key_len, &value, &val_len) == FAILURE) {
    RETURN_NULL();
}

zval *redis_obj = getThis();
zend_update_property_stringl(redis_ce, redis_obj, ZEND_STRL("_reply"), "", 0 TSRMLS_CC);

zend_call_method_with_3_params(&redis_obj, zend_get_class_entry(redis_obj TSRMLS_CC), NULL, "redis_set", NULL, key, key_len, value, val_len);

char *reply = zend_read_property(redis_ce, redis_obj, ZEND_STRL("_reply"), 0 TSRMLS_CC);
RETVAL_STRINGL(reply, strlen(reply), 1);

}

This code parses the parameters , and use the zend_call_method_with_3_params function to call the redis_set function. The SUCCESS constant indicates that the operation was successful and the response is set to the properties of the Redis object.

4. Compile the extension program

Finally, the C language code needs to be compiled into a dynamic link library. The code can be compiled into a file named redis.so using the following command:

gcc -shared -o redis.so -I/path/to/php/include/php -I/path/to/php/ include/php/main -I/path/to/php/include/php/TSRM -I/path/to/php/include/php/Zend -lphp5 -L/usr/local/lib -l hiredis redis.c

First, we need to use the gcc compiler to compile the code into a shared library. The first parameter shared tells gcc to generate a shared library. The -I/path/to/php/include/php option is to tell the compiler the location of the PHP header files to be included. Finally, the libraries required for compilation are specified.

5. Using the Redis Driver

Finally, the Redis driver is ready for use in PHP applications. The following example shows how to connect to a Redis server and store a string value:

$redis = new Redis();
$redis->connect('127.0.0.1', 6379);

$redis->set('key', 'value');

echo $redis->get('key');

This code creates a New Redis object and use the connect method to connect to the Redis server. Next, use the set method to store the string value and retrieve it in the get method.

Conclusion

In this article, we explored how to implement a Redis driver using PHP. Using a PHP extension as an entry point, we can convert the Redis protocol into a format that PHP understands and pass the request to the Redis server via the Redis C API. This makes Redis operations in PHP applications more efficient and reliable.

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