redis內存數據庫C客戶端hiredis API 中文說明

A)編譯安裝

make
make install (/usr/local)
make install PREFIX=$HOME/progs(可以自由指定安裝路徑)

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)建立連接

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

redisConnect函數用來創建一個叫redisContext的東西，它包含了連接相關的信息，它里面有個err字段，0表示正常，其他表示出錯了！通過errstr字段可以知曉錯誤信息。

2)執行命令

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的調用格式類似printf函數，上面的第二條調用語句的作用在於輸入二進制格式的value內容，其后必須表明二進制的字節長度!

3)redisCommand函數返回一個東西叫redisReply，我們需要通過判斷它的type字段來知道返回了具體什么樣的內容：

REDIS_REPLY_STATUS      表示狀態，內容通過str字段查看，字符串長度是len字段
REDIS_REPLY_ERROR       表示出錯，查看出錯信息，如上的str,len字段
REDIS_REPLY_INTEGER    返回整數，從integer字段獲取值
REDIS_REPLY_NIL            沒有數據返回
REDIS_REPLY_STRING      返回字符串，查看str,len字段
REDIS_REPLY_ARRAY       返回一個數組，查看elements的值（數組個數），通過element[index]的方式訪問數組元素，每個數組元素是 一個redisReply對象的指針

4)另外有一個類似的函數，批量執行命令：

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

5)redisReply使用完畢后，需要使用函數freeReplyObject進行釋放銷毀

void redisFree(redisContext *c)的作用是斷開連接，並釋放redisContext的內容

6)redisCommand的函數執行流程說明：
　　a.格式化redis command
　　b.格式化后的命令內容放入redisContext的輸出緩沖區
　　c.調用redisGetReply函數執行命令，得到結果

7)管道的使用方式：
a.填入需要執行的命令

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

b.獲取命令的輸出結果

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

c.釋放輸出結果

void freeReplyObject(void *reply);

例子:

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

訂閱模式：

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

8)redisReply返回結果處理：
REDIS_OK                    正常
REDIS_ERR_IO        　　IO讀/寫出現異常，通過errno查看原因
REDIS_ERR_EOF            服務器關閉了鏈接，讀結束
REDIS_ERR_PROTOCOL  分析redis協議內容出錯
EDIS_ERR_OTHER          其他未知的錯誤
上述錯誤類型都可以通過redisReply的errstr字段查看簡短的描述

C)異步API(異步API的使用方式和同步API差不多，在這兒列出不同的函數吧)
1.連接redis服務器

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

2.設置連接、斷開的鈎子函數

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);

獲取命令輸出和同步API相同

4.關閉連接

void redisAsyncDisconnect(redisAsyncContext *ac);

D)輔助API
下面的API主要用於其他編程語言綁定的術后，可以讀取分析數據

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：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <hiredis.h>

int main(int argc, char **argv) {
    unsigned int j;
    redisContext *c;
    redisReply *reply;
    const char *hostname = (argc > 1) ? argv[1] : "127.0.0.1";
    int port = (argc > 2) ? atoi(argv[2]) : 6379;

    struct timeval timeout = { 1, 500000 }; // 1.5 seconds
    c = redisConnectWithTimeout(hostname, port, timeout);
    if (c == NULL || c->err) {
        if (c) {
            printf("Connection error: %s\n", c->errstr);
            redisFree(c);
        } else {
            printf("Connection error: can't allocate redis context\n");
        }
        exit(1);
    }

    /* PING server */
    reply = redisCommand(c,"PING");
    printf("PING: %s\n", reply->str);
    freeReplyObject(reply);

    /* Set a key */
    reply = redisCommand(c,"SET %s %s", "foo", "hello world");
    printf("SET: %s\n", reply->str);
    freeReplyObject(reply);

    /* Set a key using binary safe API */
    reply = redisCommand(c,"SET %b %b", "bar", (size_t) 3, "hello", (size_t) 5);
    printf("SET (binary API): %s\n", reply->str);
    freeReplyObject(reply);

    /* Try a GET and two INCR */
    reply = redisCommand(c,"GET foo");
    printf("GET foo: %s\n", reply->str);
    freeReplyObject(reply);

    reply = redisCommand(c,"INCR counter");
    printf("INCR counter: %lld\n", reply->integer);
    freeReplyObject(reply);
    /* again ... */
    reply = redisCommand(c,"INCR counter");
    printf("INCR counter: %lld\n", reply->integer);
    freeReplyObject(reply);

    /* Create a list of numbers, from 0 to 9 */
    reply = redisCommand(c,"DEL mylist");
    freeReplyObject(reply);
    for (j = 0; j < 10; j++) {
        char buf[64];

        snprintf(buf,64,"%d",j);
        reply = redisCommand(c,"LPUSH mylist element-%s", buf);
        freeReplyObject(reply);
    }

    /* Let's check what we have inside the list */
    reply = redisCommand(c,"LRANGE mylist 0 -1");
    if (reply->type == REDIS_REPLY_ARRAY) {
        for (j = 0; j < reply->elements; j++) {
            printf("%u) %s\n", j, reply->element[j]->str);
        }
    }
    freeReplyObject(reply);

    /* Disconnects and frees the context */
    redisFree(c);

    return 0;
}

 

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