Simple use of Redis database under Linux

I. Introduction of Redis

Redis is a key-value storage system. Similar to memcached, but solves the situation where the data is completely lost after a power outage, and she supports more untyped value types, in addition to string, supports lists (linked list), sets (collection), and Zsets (ordered collection) data types. These data types support Push/pop, Add/remove, and intersection-set and difference sets, and richer operations, and these operations are atomic.

Second, the installation of Redis

First download the Redis source installation package from the official website: https://github.com/antirez/redis.git

Currently the latest branch is 3.2

1 3.2  HTTPS://github.com/antirez/redis.git

After the download is complete, enter the Redis directory and the compiled installation is directly

Make

Make install

Compile and install to run directly

Redis-server can enable Redis service, you can use the Netstat command to see the Redis listening port (default is 6379)

After Redis service, I can test the database to see if it was installed successfully.

To enable the Redis client at the command line input REDIS-CLI:

Enter the command to test if Redis is installed successfully

127.0. 0.1:6379> pingpong127.0. 0.1:6379set  test Hellook127.0. 0.1:6379get  test"hello"127.0 . 0.1:6379>

For more Redis commands, refer to the Redis command manual, which details the usage of REDIS-CLI commands

http://doc.redisfans.com/

At this point, the Redis database installation is complete

Third, the installation of the Redis C interface Library

Redis is a high-performance Key-value database. The emergence of Redis, to a large extent, compensates for the lack of memcached such key/value storage, in some cases can be a good complement to the relational database. It provides the Java,c/c++,c#,php,javascript,perl,object-c,python,ruby,erlang and other clients, the use is very convenient

Here is a brief introduction to Redis's C interface library:

Hiredis is the C-interface Library of Redis, we need to download the installation before using Hiredis,:https://github.com/redis/hiredis.git

git clone https://github.com/redis/hiredis.git

Enter Hiredis directory after download

Make

Make install

Here are some common functions introduced in the Hredis library

(1) Redisconnect function

This function is used to connect a Redis database

Function Prototypes:

1  Rediscontext *redisconnect (constcharint  port); 2 // Note: This function is used to connect the Redis database with the IP address and port of the database, and the general Redis database has a port of 6379 which returns a struct rediscontext. 

The REDISCONTEXT structure is defined as follows:

1 /*Context for a connection to Redis*/2typedefstructRediscontext {3     intErr/*error flags, 0 when there is no Error*/4     Charerrstr[ -];/*String representation of error when applicable*/5     intFD;6     intflags;7     Char*obuf;/*Write Buffer*/8Redisreader *reader;/*Protocol Reader*/9 Ten     enumRedisconnectiontype Connection_type; One     structTimeval *timeout; A  -     struct { -         Char*host; the         Char*source_addr; -         intPort; - } TCP; -  +     struct { -         Char*path; + } unix_sock; A  at} Rediscontext;

(2) Rediscommand function

This function is used to execute REDIS commands;

Function Prototypes:

1 void Const Char *format, ...); 2 /* Description: The function executes a command, just like an SQL statement in a SQL database, only executes the operations command in the Redis database. 3 The first parameter is the Rediscontext returned when the database is connected, 4 followed by a mutable argument list, similar to the C language printf function, 5 The return value is void*, and the generic cast becomes the redisreply type for further processing. */

Usage:

Redisreply *reply = (redisreply*) rediscommand (c, CMD);

(3) Redisrelpyobject function

The function is also used to release the memory occupied by the Rediscommand return value redisreply

1 /*  */2void freereplyobject (void *reply)3//  This function is used to reclaim the memory occupied by releasing the Rediscommand return value redisreply

(4) Redisfree function

This function is used to release a connection to a Redis database

1 void redisfree (rediscontext *c)2// for releasing Redisconnect-generated connections

Below is a simple Redis test program for Hredis C interface:

#include <stdio.h>#include<string.h>#include<stddef.h>#include<stdarg.h>#include<string.h>#include<assert.h>#include#defineRedis_host "127.0.0.1"#defineRedis_port 6379voidredis_cli () {Rediscontext*c =NULL; Redisreply*r =NULL; C=Redisconnect (Redis_host, Redis_port); if(NULL = =c) {printf ("Connect Redis Server failure\n"); return; } printf ("redis Connect sucess IP:%s Port:%d\n", Redis_host, Redis_port); Char*CMD1 ="Set Test Hello"; R= (redisreply*) Rediscommand (c, CMD1); if(NULL = =r) {printf ("Redis Command Error [%s]\n", CMD1);          Redisfree (c); return; }       if(R->type = =redis_reply_error) {printf ("Redis command[%s], error:%s\n", CMD1, r->str);        Freereplyobject (R);          Redisfree (c); return; } printf ("redis Command Execute success[%s]\n", CMD1);    Freereplyobject (R); Char*CMD2 ="Get Test"; R= (redisreply*) Rediscommand (c, CMD2); if(NULL = =r) {printf ("Redis Command Error [%s]\n", CMD2);          Redisfree (c); return; }       if(R->type = =redis_reply_error) {printf ("Redis command[%s], error:%s\n", CMD2, r->str);        Freereplyobject (R);          Redisfree (c); return; } printf ("Get test value is:%s\n", r->str);    Freereplyobject (R); Const Char* Cmd3 ="strlen Test"; R= (redisreply*) Rediscommand (c, CMD3); if(R->type! =Redis_reply_integer) {printf ("Failed to execute command[%s]\n", CMD3);          Freereplyobject (R);          Redisfree (c); return; } printf ("The length of ' test ' is%d.\n", r->integer);      Freereplyobject (R);      Redisfree (c); return;}intMainintargcChar**argv)        {redis_cli (); return 0;}

Operation Result:

[Email protected] 3rd]#./127.0. 0.1  6379 redis Command Execute success[set  test Hello] Get  is  'test'is5

Simple use of Redis database under Linux