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Pieter Noordhuis 2011-04-21 23:50:26 +02:00
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README.md
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@ -303,33 +303,41 @@ See the `adapters/` directory for bindings to *libev* and *libevent*.
## Reply parsing API
Hiredis comes with a reply parsing API that makes it easy for writing higher level language bindings.
Hiredis comes with a reply parsing API that makes it easy for writing higher
level language bindings.
The reply parsing API consists of the following functions:
void *redisReplyReaderCreate(void);
void redisReplyReaderFeed(void *reader, const char *buf, size_t len);
int redisReplyReaderGetReply(void *reader, void **reply);
int redisReplyReaderSetReplyObjectFunctions(void *reader, redisReplyObjectFunctions *fn);
redisReader *redisReaderCreate(void);
void redisReaderFree(redisReader *reader);
int redisReaderFeed(redisReader *reader, const char *buf, size_t len);
int redisReaderGetReply(redisReader *reader, void **reply);
### Creating redisReader
### Usage
The function `redisReplyReaderCreate` creates `redisReader` struct variable that primarily holds data read from the socket.
The function `redisReaderCreate` creates a `redisReader` structure that holds a
buffer with unparsed data and state for the protocol parser.
### Reading data
Incoming data -- most likely from a socket -- can be placed in the internal
buffer of the `redisReader` using `redisReaderFeed`. This function will make a
copy of the buffer pointed to by `buf` for `len` bytes. This data is parsed
when `redisReaderGetReply` is called. This function returns an integer status
and a reply object (as described above) via `void **reply`. The returned status
can be either `REDIS_OK` or `REDIS_ERR`, where the latter means something went
wrong (either a protocol error, or an out of memory error).
The function `redisReplyReaderFeed` populates `buf` and `len` fields of `redisReader` with the data read from socket and it's length respectively.
### Customizing replies
### Creating reply objects from the data in the socket
The function `redisReaderGetReply` creates `redisReply` and makes the function
argument `reply` point to the created `redisReply` variable. For instance, if
the response of type `REDIS_REPLY_STATUS` then the `str` field of `redisReply`
will hold the status as a vanilla C string. However, the functions that are
responsible for creating instances of the `redisReply` can be customized by
setting the `fn` field on the `redisReader` struct. This should be done
immediately after creating the `redisReader`.
The function `redisReplyReaderGetReply` creates `redisReply` and makes the function argument `reply` point to the created `redisReply` variable. For instance,
if the response of type `REDIS_REPLY_STATUS` then the `str` field of `redisReply` will hold the status as a C string. However, `redisReply` variables are not
directly created by `redisReplyReaderGetReply`. `redisReader` has a field `fn` of type `redisReplyObjectFunctions` that is essentially a set of pointers to functions.
So the function pointer `createString` points to a function that is called when a response of type `REDIS_REPLY_STATUS` is received.
Thus, the function `redisReplyReaderSetReplyObjectFunctions` can be used to tell hiredis to use a custom set of functions instead of the provided default.
For example, the hiredis-rb [client](https://github.com/pietern/hiredis-rb/blob/master/ext/hiredis_ext/reader.c) calls `redisReplyReaderSetReplyObjectFunctions` to set the function pointers to custom functions that create Ruby objects.
For example, [hiredis-rb](https://github.com/pietern/hiredis-rb/blob/master/ext/hiredis_ext/reader.c)
uses customized reply object functions to create Ruby objects.
## AUTHORS