【转】redis C接口hiredis 简单函数使用介绍

from : http://blog.csdn.net/kingqizhou/article/details/8104693

hiredis是redis数据库的C接口，目前只能在linux下使用，几个基本的函数就可以操作redis数据库了。

函数原型：redisContext *redisConnect(const char *ip, int port)

说明：该函数用来连接redis数据库，参数为数据库的ip地址和端口，一般redis数据库的端口为6379

该函数返回一个结构体redisContext。

函数原型：void *redisCommand(redisContext *c, const char *format, ...);

说明：该函数执行命令，就如sql数据库中的SQL语句一样，只是执行的是redis数据库中的操作命令，第一个参数为连接数据库时返回的redisContext，剩下的参数为变参，就如C标准函数printf函数一样的变参。返回值为void*，一般强制转换成为redisReply类型的进行进一步的处理。

函数原型void freeReplyObject(void *reply);

说明：释放redisCommand执行后返回的redisReply所占用的内存

函数原型：void redisFree(redisContext *c);

说明：释放redisConnect()所产生的连接。

下面用一个简单的例子说明：

#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <stdarg.h>
#include <string.h>
#include <assert.h>
#include "hiredis.h"

void doTest()
{
    //redis默认监听端口为6387 可以再配置文件中修改
    redisContext* c = redisConnect("127.0.0.1", 6379);
    if ( c->err)
    {
        printf("Connect to redisServer faile:%s
",c->errstr);
        redisFree(c);
        return ;
    }
    printf("Connect to redisServer Success
");

    const char* command1 = "set stest1 value1";
    redisReply* r = (redisReply*)redisCommand(c, command1);

    if( NULL == r)
    {
        printf("Execut command1 failure
");
        redisFree(c);
        return;
    }
    if( !(r->type == REDIS_REPLY_STATUS && (strcmp(r->str,"OK")==0 || strcmp(r->str,"ok")==0 ) ))
    {
        printf("Failed to execute command[%s]
",command1);
        freeReplyObject(r);
        redisFree(c);
        return;
    }    
    freeReplyObject(r);
    printf("Succeed to execute command[%s]
", command1);

    const char* command2 = "strlen stest1";
    r = (redisReply*)redisCommand(c, command2);
    if ( r->type != REDIS_REPLY_INTEGER)
    {
        printf("Failed to execute command[%s]
",command2);
        freeReplyObject(r);
        redisFree(c);
        return;
    }
    int length =  r->integer;
    freeReplyObject(r);
    printf("The length of 'stest1' is %d.
", length);
    printf("Succeed to execute command[%s]
", command2);


    const char* command3 = "get stest1";
    r = (redisReply*)redisCommand(c, command3);
    if ( r->type != REDIS_REPLY_STRING)
    {
        printf("Failed to execute command[%s]
",command3);
        freeReplyObject(r);
        redisFree(c);
        return;
    }
    printf("The value of 'stest1' is %s
", r->str);
    freeReplyObject(r);
    printf("Succeed to execute command[%s]
", command3);

    const char* command4 = "get stest2";
    r = (redisReply*)redisCommand(c, command4);
    if ( r->type != REDIS_REPLY_NIL)
    {
        printf("Failed to execute command[%s]
",command4);
        freeReplyObject(r);
        redisFree(c);
        return;
    }
    freeReplyObject(r);
    printf("Succeed to execute command[%s]
", command4);    


    redisFree(c);

}

int main()
{
    WSADATA wsaData;
    int nRet;
    if((nRet = WSAStartup(MAKEWORD(2,2),&wsaData)) != 0){
        printf("WSAStartup failed
");
        exit(0);
    }
    doTest();
    return 0;
}

执行结果为：