redis内存数据库C客户端hiredis API 中文说明

A)编译安装

makemake install (/usr/local)make install PREFIX=$HOME/progs(可以自由指定安装路径)

B)同步的API接口

redisContext *redisConnect(const char *ip, int port);void *redisCommand(redisContext *c, const char *format, ...);void freeReplyObject(void *reply);

1)建立连接

redisContext *c = redisConnect("127.0.0.1", 6379);if (c != NULL && c->err) {        printf("Error: %s\n", c->errstr);            // handle error}

redisConnect函数用来创建一个叫redisContext的东西，它包含了连接相关的信息，它里面有个err字段，0表示正常，其他表示出错了！通过errstr字段可以知晓错误信息。

2)执行命令

reply = redisCommand(context, "SET key value");reply = redisCommand(context, "SET key %s", value);reply = redisCommand(context, "SET key %b", value, (size_t) valuelen);reply = redisCommand(context, "SET key:%s %s", myid, value);

redisCommand的调用格式类似printf函数，上面的第二条调用语句的作用在于输入二进制格式的value内容，其后必须表明二进制的字节长度!

3)redisCommand函数返回一个东西叫redisReply，我们需要通过判断它的type字段来知道返回了具体什么样的内容：

REDIS_REPLY_STATUS      表示状态，内容通过str字段查看，字符串长度是len字段REDIS_REPLY_ERROR       表示出错，查看出错信息，如上的str,len字段REDIS_REPLY_INTEGER    返回整数，从integer字段获取值REDIS_REPLY_NIL            没有数据返回REDIS_REPLY_STRING      返回字符串，查看str,len字段REDIS_REPLY_ARRAY       返回一个数组，查看elements的值（数组个数），通过element[index]的方式访问数组元素，每个数组元素是 一个redisReply对象的指针

4)另外有一个类似的函数，批量执行命令：

void *redisCommandArgv(redisContext *c, int argc, const char **argv, const size_t *argvlen);

5)redisReply使用完毕后，需要使用函数freeReplyObject进行释放销毁

void redisFree(redisContext *c)的作用是断开连接，并释放redisContext的内容

6)redisCommand的函数执行流程说明：
　　a.格式化redis command
　　b.格式化后的命令内容放入redisContext的输出缓冲区
　　c.调用redisGetReply函数执行命令，得到结果

7)管道的使用方式：
a.填入需要执行的命令

void redisAppendCommand(redisContext *c, const char *format, ...);void redisAppendCommandArgv(redisContext *c, int argc, const char **argv, const size_t *argvlen);

b.获取命令的输出结果

int redisGetReply(redisContext *c, void **reply);

c.释放输出结果

void freeReplyObject(void *reply);

例子:

redisReply *reply = NULL;redisAppendCommand(context,"set key1 value");redisAppendCommand(context,"get key2");redisGetReply(context,&reply); // reply for setfreeReplyObject(reply);redisGetReply(context,&reply); // reply for getfreeReplyObject(reply);

订阅模式：

reply = redisCommand(context,"SUBSCRIBE test");freeReplyObject(reply);while(redisGetReply(context,&reply) == REDIS_OK) {        // consume message        freeReplyObject(reply);}

8)redisReply返回结果处理：
REDIS_OK                    正常
REDIS_ERR_IO        　　IO读/写出现异常，通过errno查看原因
REDIS_ERR_EOF            服务器关闭了链接，读结束
REDIS_ERR_PROTOCOL  分析redis协议内容出错
EDIS_ERR_OTHER          其他未知的错误
上述错误类型都可以通过redisReply的errstr字段查看简短的描述

C)异步API(异步API的使用方式和同步API差不多，在这儿列出不同的函数吧)
1.连接redis服务器

redisAsyncContext *c = redisAsyncConnect("127.0.0.1", 6379);if (c->err) {        printf("Error: %s\n", c->errstr);            // handle error}

2.设置连接、断开的钩子函数

int redisAsyncSetConnectCallback(redisAsyncContext *ac, redisConnectCallback *fn);int redisAsyncSetDisconnectCallback(redisAsyncContext *ac, redisDisconnectCallback *fn);

3.插入命令信息

int redisAsyncCommand(redisAsyncContext *ac, redisCallbackFn *fn, void *privdata,const char *format, ...);int redisAsyncCommandArgv( redisAsyncContext *ac, redisCallbackFn *fn, void *privdata, int argc, const char **argv, const size_t *argvlen);

获取命令输出和同步API相同

4.关闭连接

void redisAsyncDisconnect(redisAsyncContext *ac);

D)辅助API
下面的API主要用于其他编程语言绑定的术后，可以读取分析数据

redisReader *redisReaderCreate(void);void redisReaderFree(redisReader *reader);int redisReaderFeed(redisReader *reader, const char *buf, size_t len);int redisReaderGetReply(redisReader *reader, void **reply);

 官方例子：

 1 #include <stdio.h> 2 #include <stdlib.h> 3 #include <string.h> 4  5 #include <hiredis.h> 6  7 int main(int argc, char **argv) { 8     unsigned int j; 9     redisContext *c;10     redisReply *reply;11     const char *hostname = (argc > 1) ? argv[1] : "127.0.0.1";12     int port = (argc > 2) ? atoi(argv[2]) : 6379;13 14     struct timeval timeout = { 1, 500000 }; // 1.5 seconds15     c = redisConnectWithTimeout(hostname, port, timeout);16     if (c == NULL || c->err) {17         if (c) {18             printf("Connection error: %s\n", c->errstr);19             redisFree(c);20         } else {21             printf("Connection error: can't allocate redis context\n");22         }23         exit(1);24     }25 26     /* PING server */27     reply = redisCommand(c,"PING");28     printf("PING: %s\n", reply->str);29     freeReplyObject(reply);30 31     /* Set a key */32     reply = redisCommand(c,"SET %s %s", "foo", "hello world");33     printf("SET: %s\n", reply->str);34     freeReplyObject(reply);35 36     /* Set a key using binary safe API */37     reply = redisCommand(c,"SET %b %b", "bar", (size_t) 3, "hello", (size_t) 5);38     printf("SET (binary API): %s\n", reply->str);39     freeReplyObject(reply);40 41     /* Try a GET and two INCR */42     reply = redisCommand(c,"GET foo");43     printf("GET foo: %s\n", reply->str);44     freeReplyObject(reply);45 46     reply = redisCommand(c,"INCR counter");47     printf("INCR counter: %lld\n", reply->integer);48     freeReplyObject(reply);49     /* again ... */50     reply = redisCommand(c,"INCR counter");51     printf("INCR counter: %lld\n", reply->integer);52     freeReplyObject(reply);53 54     /* Create a list of numbers, from 0 to 9 */55     reply = redisCommand(c,"DEL mylist");56     freeReplyObject(reply);57     for (j = 0; j < 10; j++) {58         char buf[64];59 60         snprintf(buf,64,"%d",j);61         reply = redisCommand(c,"LPUSH mylist element-%s", buf);62         freeReplyObject(reply);63     }64 65     /* Let's check what we have inside the list */66     reply = redisCommand(c,"LRANGE mylist 0 -1");67     if (reply->type == REDIS_REPLY_ARRAY) {68         for (j = 0; j < reply->elements; j++) {69             printf("%u) %s\n", j, reply->element[j]->str);70         }71     }72     freeReplyObject(reply);73 74     /* Disconnects and frees the context */75     redisFree(c);76 77     return 0;78 }

 

整理自：http://www.mamicode.com/info-detail-501902.html

FROM:  http://www.cnblogs.com/houjun/p/4875116.html