In order to use Redis with C you will need a C Redis client. In following sections, we will demonstrate the use of hiredis, a simple C client for Redis. Additional C clients for Redis can be found under the C section of the Redis Clients page.

Installing hiredis

Download the latest hiredis release from the GitHub repository.

Opening a Connection to Redis Using hiredis

The following code creates a connection to Redis using hiredis' synchronous API:

#include "hiredis.h"

redisContext *c = redisConnect("hostname", port);
if (c != NULL && c->err) {
    printf("Error: %s\n", c->errstr);
    // handle error
} else {
    printf("Connected to Redis\n");
}

redisReply *reply;
reply = redisCommand(c, "AUTH password");
freeReplyObject(reply);

...

redisFree(c);

To adapt this example to your code, make sure that you replace the following values with those of your database:

  • In line 1, the first argument to redisConnect should be your database's hostname or IP address
  • In line 1, the second argument to redisConnect should be your database's port
  • In line 6, replace "password" with your database's password

Using SSL and hiredis

hiredis does not support SSL connections natively. For an added security measure, you can secure the connection using stunnel.

Reading and Writing Data with hiredis

Once connected to Redis, you can start reading and writing data. The following code snippet writes the value bar to the Redis key foo, reads it back, and prints it:

// open a connection to Redis
...

redisReply *reply;

reply = redisCommand(c,"SET %s %s","foo","bar");
freeReplyObject(reply);

reply = redisCommand(c,"GET %s","foo");
printf("%s\n",reply->str);
freeReplyObject(reply);

The output of the above code should be:

$ gcc example_hiredis.c -o example_hiredis
$ ./example_hiredis
Connected to Redis
bar