Connecting to Redis on phpredis (PHP)

This section describes how to connect to Redis on phpredis. For more information about how to use other Redis clients, visit the Redis official website.

The following operations are based on an example of accessing a Redis instance on a client on an elastic cloud server (ECS).

The operations described in this section apply only to single-node, master/standby, and Proxy Cluster instances. To use phpredis to connect to a Redis Cluster instance, see the phpredis description.

Prerequisites

A Redis instance is created, and is in the Running state.
An ECS has been created. For details about how to create an ECS, see Elastic Cloud Server User Guide
If the ECS runs the Linux OS, ensure that the GCC compilation environment has been installed on the ECS.

Connecting to Redis on phpredis

View the IP address/domain name and port number of the DCS Redis instance to be accessed.

For details, see Distributed Cache Service User Guide > "Getting Started" > "Viewing Details of a DCS Instance".
Log in to the ECS.

The following uses CentOS as an example to describe how to access an instance through phpredis.
Install GCC-C++ and Make compilation components.

yum install gcc-c++ make
Install the PHP development package and CLI tool.

Run the following yum command to install the PHP development package:

yum install php-devel php-common php-cli

After the installation is complete, run the following command to query the PHP version and check whether the installation is successful:

php --version
Install the phpredis client.
1. Download the source phpredis package.
  wget http://pecl.php.net/get/redis-5.3.7.tgz
  
  This version is used as an example. To download phpredis clients of other versions, visit the Redis or PHP official website.
2. Decompress the source phpredis package.
  tar -zxvf redis-5.3.7.tgz
  
  cd redis-5.3.7
3. Command before compilation.
  phpize
4. Configure the php-config file.
  ./configure --with-php-config=/usr/bin/php-config
  
  The location of the file varies depending on the OS and PHP installation mode. You are advised to locate the directory where the file is saved before the configuration.
  
  find / -name php-config
5. Compile and install the phpredis client.
  make && make install
6. After the installation, add the extension configuration in the php.ini file to reference the Redis module.
  vim /etc/php.ini
  
  Add the following configuration:
```
extension = "/usr/lib64/php/modules/redis.so"
```
  The redis.so file may be saved in a different directory from php.ini. Run the following command to locate the directory:
  
  find / -name php.ini
7. Save the configuration and exit. Then, run the following command to check whether the extension takes effect:
  php -m |grep redis
  
  If the command output contains redis, the phpredis client environment has been set up.
Access the DCS instance by using phpredis.
1. Edit a redis.php file.
```
<?php
    $redis_host = "{redis_instance_address}";
    $redis_port = {port};
    $user_pwd = "{password}";
    $redis = new Redis();
    if ($redis->connect($redis_host, $redis_port) == false) {
       die($redis->getLastError());
    }
    if ($redis->auth($user_pwd) == false) {
        die($redis->getLastError());
    }
    if ($redis->set("welcome", "Hello, DCS for Redis!") == false) {
        die($redis->getLastError());
    }
    $value = $redis->get("welcome");
    echo $value;
    $redis->close();
?>
```
  {redis_instance_address} indicates the example IP address/domain name of the DCS instance and {port} indicates the port number of the DCS instance. For details about how to obtain the IP address/domain name and port, see 1. Change them as required. {password} indicates the password used to log in to the chosen DCS Redis instance. This password is defined during DCS Redis instance creation. If password-free access is enabled, shield the if statement for password authentication.
2. Run the php redis.php command to access the DCS instance.