# HIREDIS
Hiredis is a minimalistic C client library for the [Redis](http://redis.io/) database.
It is minimalistic because it just adds minimal support for the protocol, but
at the same time it uses an high level printf-alike API in order to make it
much higher level than otherwise suggested by its minimal code base and the
lack of explicit bindings for every Redis command.
Apart from supporting sending commands and receiving replies, it comes with
a reply parser that is decoupled from the I/O layer. It
is a stream parser designed for easy reusability, which can for instance be used
in higher level language bindings for efficient reply parsing.
Hiredis only supports the binary-safe Redis protocol, so you can use it with any
Redis version >= 1.2.0.
The library comes with multiple APIs. There is the
*synchronous API*, the *asynchronous API* and the *reply parsing API*.
## UPGRADING
Version 0.9.0 is a major overhaul of hiredis in every aspect. However, upgrading existing
code using hiredis should not be a big pain. The key thing to keep in mind when
upgrading is that hiredis >= 0.9.0 uses a `redisContext*` to keep state, in contrast to
the stateless 0.0.1 that only has a file descriptor to work with.
## Synchronous API
To consume the synchronous API, there are only a few function calls that need to be introduced:
redisContext *redisConnect(const char *ip, int port);
void *redisCommand(redisContext *c, const char *format, ...);
void freeReplyObject(void *reply);
### Connecting
The function `redisConnect` is used to create a so-called `redisContext`. The
context is where Hiredis holds state for a connection. The `redisContext`
struct has an integer `err` field that is non-zero when an the connection is in
an error state. The field `errstr` will contain a string with a description of
the error. More information on errors can be found in the **Errors** section.
After trying to connect to Redis using `redisConnect` you should
check the `err` field to see if establishing the connection was successful:
redisContext *c = redisConnect("127.0.0.1", 6379);
if (c->err) {
printf("Error: %s\n", c->errstr);
// handle error
}
### Sending commands
There are several ways to issue commands to Redis. The first that will be introduced is
`redisCommand`. This function takes a format similar to printf. In the simplest form,
it is used like this:
reply = redisCommand(context, "SET foo bar");
The specifier `%s` interpolates a string in the command, and uses `strlen` to
determine the length of the string:
reply = redisCommand(context, "SET foo %s", value);
When you need to pass binary safe strings in a command, the `%b` specifier can be
used. Together with a pointer to the string, it requires a `size_t` length argument
of the string:
reply = redisCommand(context, "SET foo %b", value, valuelen);
Internally, Hiredis splits the command in different arguments and will
convert it to the protocol used to communicate with Redis.
One or more spaces separates arguments, so you can use the specifiers
anywhere in an argument:
reply = redisCommand(context, "SET key:%s %s", myid, value);
### Using replies
The return value of `redisCommand` holds a reply when the command was
successfully executed. When an error occurs, the return value is `NULL` and
the `err` field in the context will be set (see section on **Errors**).
Once an error is returned the context cannot be reused and you should set up
a new connection.
The standard replies that `redisCommand` are of the type `redisReply`. The
`type` field in the `redisReply` should be used to test what kind of reply
was received:
* **`REDIS_REPLY_STATUS`**:
* The command replied with a status reply. The status string can be accessed using `reply->str`.
The length of this string can be accessed using `reply->len`.
* **`REDIS_REPLY_ERROR`**:
* The command replied with an error. The error string can be accessed identical to `REDIS_REPLY_STATUS`.
* **`REDIS_REPLY_INTEGER`**:
* The command replied with an integer. The integer value can be accessed using the
`reply->integer` field of type `long long`.
* **`REDIS_REPLY_NIL`**:
* The command replied with a **nil** object. There is no data to access.
* **`REDIS_REPLY_STRING`**:
* A bulk (string) reply. The value of the reply can be accessed using `reply->str`.
The length of this string can be accessed using `reply->len`.
* **`REDIS_REPLY_ARRAY`**:
* A multi bulk reply. The number of elements in the multi bulk reply is stored in
`reply->elements`. Every element in the multi bulk reply is a `redisReply` object as well
and can be accessed via `reply->element[..index..]`.
Redis may reply with nested arrays but this is fully supported.
Replies should be freed using the `freeReplyObject()` function.
Note that this function will take care of freeing sub-replies objects
contained in arrays and nested arrays, so there is no need for the user to
free the sub replies (it is actually harmful and will corrupt the memory).
**Important:** the current version of hiredis (0.10.0) free's replies when the
asynchronous API is used. This means you should not call `freeReplyObject` when
you use this API. The reply is cleaned up by hiredis _after_ the callback
returns. This behavior will probably change in future releases, so make sure to
keep an eye on the changelog when upgrading (see issue #39).
### Cleaning up
To disconnect and free the context the following function can be used:
void redisFree(redisContext *c);
This function immediately closes the socket and then free's the allocations done in
creating the context.
### Sending commands (cont'd)
Together with `redisCommand`, the function `redisCommandArgv` can be used to issue commands.
It has the following prototype:
void *redisCommandArgv(redisContext *c, int argc, const char **argv, const size_t *argvlen);
It takes the number of arguments `argc`, an array of strings `argv` and the lengths of the
arguments `argvlen`. For convenience, `argvlen` may be set to `NULL` and the function will
use `strlen(3)` on every argument to determine its length. Obviously, when any of the arguments
need to be binary safe, the entire array of lengths `argvlen` should be provided.
The return value has the same semantic as `redisCommand`.
### Pipelining
To explain how Hiredis supports pipelining in a blocking connection, there needs to be
understanding of the internal execution flow.
When any of the functions in the `redisCommand` family is called, Hiredis first formats the
command according to the Redis protocol. The formatted command is then put in the output buffer
of the context. This output buffer is dynamic, so it can hold any number of commands.
After the command is put in the output buffer, `redisGetReply` is called. This function has the
following two execution paths:
1. The input buffer is non-empty:
* Try to parse a single reply from the input buffer and return it
* If no reply could be parsed, continue at *2*
2. The input buffer is empty:
* Write the **entire** output buffer to the socket
* Read from the socket until a single reply could be parsed
The function `redisGetReply` is exported as part of the Hiredis API and can be used when a reply
is expected on the socket. To pipeline commands, the only things that needs to be done is
filling up the output buffer. For this cause, two commands can be used that are identical
to the `redisCommand` family, apart from not returning a reply:
void redisAppendCommand(redisContext *c, const char *format, ...);
void redisAppendCommandArgv(redisContext *c, int argc, const char **argv, const size_t *argvlen);
After calling either function one or more times, `redisGetReply` can be used to receive the
subsequent replies. The return value for this function is either `REDIS_OK` or `REDIS_ERR`, where
the latter means an error occurred while reading a reply.
没有合适的资源?快使用搜索试试~ 我知道了~
带有详细注释的 Redis 3.0 代码.zip
共427个文件
c:141个
h:96个
tcl:62个
需积分: 3 1 下载量 186 浏览量
2023-11-07
18:06:29
上传
评论
收藏 1.51MB ZIP 举报
温馨提示
redis 带有详细注释的 Redis 3.0 代码.zip带有详细注释的 Redis 3.0 代码.zip带有详细注释的 Redis 3.0 代码.zip带有详细注释的 Redis 3.0 代码.zip带有详细注释的 Redis 3.0 代码.zip带有详细注释的 Redis 3.0 代码.zip
资源推荐
资源详情
资源评论
收起资源包目录
带有详细注释的 Redis 3.0 代码.zip (427个子文件)
00-RELEASENOTES 633B
lua.1 4KB
luac.1 4KB
jemalloc.3 49KB
configure.ac 38KB
luavs.bat 1KB
BUGS 52B
cluster.c 221KB
sentinel.c 193KB
redis.c 157KB
t_zset.c 116KB
replication.c 92KB
config.c 79KB
ziplist.c 77KB
networking.c 77KB
arena.c 69KB
aof.c 65KB
redis-cli.c 62KB
rdb.c 59KB
hyperloglog.c 56KB
t_list.c 53KB
dict.c 52KB
db.c 51KB
scripting.c 51KB
ctl.c 45KB
t_set.c 45KB
sds.c 43KB
jemalloc.c 43KB
lua_cjson.c 37KB
hiredis.c 36KB
lparser.c 36KB
debug.c 35KB
linenoise.c 35KB
t_hash.c 33KB
object.c 30KB
prof.c 29KB
sds.c 28KB
intset.c 27KB
redis-benchmark.c 27KB
zipmap.c 27KB
sort.c 27KB
bitops.c 25KB
lstrlib.c 23KB
lvm.c 23KB
test.c 23KB
lua_cmsgpack.c 22KB
lapi.c 22KB
redis-check-dump.c 22KB
async.c 21KB
lcode.c 21KB
ae.c 21KB
t_string.c 20KB
pubsub.c 20KB
lgc.c 20KB
loadlib.c 19KB
anet.c 18KB
util.c 17KB
lauxlib.c 17KB
multi.c 17KB
lbaselib.c 17KB
stats.c 17KB
ldebug.c 16KB
ltable.c 16KB
ckh.c 15KB
ldo.c 15KB
adlist.c 15KB
util.c 13KB
liolib.c 13KB
tcache.c 13KB
llex.c 12KB
bio.c 11KB
lua_struct.c 11KB
ae_evport.c 11KB
chunk.c 10KB
crc64.c 10KB
dict.c 10KB
lua.c 10KB
ldblib.c 10KB
zmalloc.c 10KB
rio.c 10KB
memtest.c 9KB
net.c 9KB
redis-check-aof.c 9KB
lzf_c.c 9KB
slowlog.c 9KB
ltablib.c 7KB
sha1.c 7KB
zone.c 7KB
blocked.c 7KB
huge.c 7KB
notify.c 6KB
strbuf.c 6KB
quarantine.c 6KB
loslib.c 6KB
lmathlib.c 6KB
ae_epoll.c 6KB
lstate.c 6KB
setproctitle.c 6KB
syncio.c 5KB
pqsort.c 5KB
共 427 条
- 1
- 2
- 3
- 4
- 5
资源评论
z同学的编程之路
- 粉丝: 2499
- 资源: 2135
上传资源 快速赚钱
- 我的内容管理 展开
- 我的资源 快来上传第一个资源
- 我的收益 登录查看自己的收益
- 我的积分 登录查看自己的积分
- 我的C币 登录后查看C币余额
- 我的收藏
- 我的下载
- 下载帮助
最新资源
- tensorflow-gpu-2.5.0-cp39-cp39-manylinux2010-x86-64.whl
- tensorflow-gpu-2.5.2-cp39-cp39-manylinux2010-x86-64.whl
- 内含方正小标宋简体、仿宋-Gb2312、黑体、楷体、宋体,五个公文常用字体
- 记忆卡牌游戏源码及可运行文件
- 利用wps的js宏编写的一键格式修改辅助工具
- 基于matlab实现训练RBF网络的,但用的算法是梯度下降法,算法仍然是自己写的.rar
- 基于matlab实现小波分析改造后,可以分析脑电数据的程序,出现32个导联每个通道的功率谱.rar
- 基于matlab实现物体的应力和应变DIC-通过识别一系列图像的变形得到物体的应力和应变
- 基于matlab实现文档+程序NSGA-II多目标优化的matlab代码.rar
- 基于matlab实现文档+程序 多目标优化,NSGA2算法实现.rar
资源上传下载、课程学习等过程中有任何疑问或建议,欢迎提出宝贵意见哦~我们会及时处理!
点击此处反馈
安全验证
文档复制为VIP权益,开通VIP直接复制
信息提交成功