lua-redis-parser - Redis reply parser and request constructor library for Lua
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This document describes lua-redis-parser v0.13 released on 8 April 2017.
This lua library implements a thin and fast redis raw response parser that constructs corresponding lua data strucutres, as well as a function that constructs redis raw requests.
To maximize speed, this module is implemented in pure C.
This library is usually used by Lua code running atop lua-nginx-module to access redis backends though redis2-nginx-module.
The parser variable used below is referring to the variable holding the return value of require "redis.parser". In other words, we assume you have written the following code first:
local parser = require "redis.parser"syntax: res, typ = parser.parse_reply(raw_reply)
Parses the single (or the first) raw redis reply from the raw_reply string and returns the Lua data structure res, as well as the reply type typ.
Here is an example:
local parser = require 'redis.parser'
-- assuming the reply variable holds the (single) redis response
-- to be parsed:
local res, typ = parser.parse_reply(reply)
if typ == parser.BAD_REPLY then
-- res is the textual error message from the parser
elseif typ == parser.INTEGER_REPLY then
-- res is an integer, like 3, returned from the redis server
elseif typ == parser.ERROR_REPLY then
-- res is the error message from the redis2 server
elseif typ == parser.STATUS_REPLY then
-- res is the textual message from the redis server
elseif typ == parser.BULK_REPLY then
--- res is a string for the bulk data
elseif typ == parser.MULTI_BULK_REPLY then
-- res is a lua (array) table that holds the individual bulks
endsyntax: results = parser.parse_replies(raw_replies)
Similar to the parse_reply method, but parse multiple pipelined redis replies in the raw_replies string argument. Returns a table of all the parsed results where each result is an array-like table consists of two elements, res and typ, which have exactly the same meaning as the return values of the parse_reply function.
For instance,
local parser = require "redis.parser"
-- assuming the replies variable holds n redis responses
-- to be parsed:
local results = parser.parse_replies(replies, n)
for i, result in ipairs(results) do
local res = result[1]
local typ = result[2]
-- res and typ have exactly the same meaning as in
-- the parse_reply method documented above
endsyntax: str = parser.typename(typ)
Returns the textual representation of the reply type values returned by the parse_reply and parse_replies functions. Here's the correspondence:
parser.typename(parser.BAD_REPLY) == "bad reply"
parser.typename(parser.INTEGER_REPLY) == "integer reply"
parser.typename(parser.ERROR_REPLY) == "error reply"
parser.typename(parser.STATUS_REPLY) == "status reply"
parser.typename(parser.BULK_REPLY) == "bulk reply"
parser.typename(parser.MULTI_BULK_REPLY) == "multi-bulk reply"syntax: raw_request = parser.build_query(args)
Constructs a raw Redis request from simple Lua values. It simply accepts a Lua array-like table, a list of parameters including the command name.
Please check out the complete list of redis 2.0 commands,
The first command in that list, "APPEND key value", for example, we can just use
local parser = require "redis.parser"
local req = parser.build_query({'APPEND', 'some-key', 'some-value'})to construct a binary request in the return value. Because the Redis command is case insensitive, I usually just use 'append', the lower case form, as the first element of that list, as in
local parser = require "redis.parser"
local req = parser.build_query({'set', 'foo', 'some value'})
-- req is the raw TCP request ready to send to the remote redis server
-- over the TCP connectionNull values should be specified by parser.null rather than Lua's nil value.
Boolean values will be converted to 1 or 0, for true and false, respectively.
syntax: typ = parser.BAD_REPLY
syntax: typ = parser.INTEGER_REPLY
syntax: typ = parser.ERROR_REPLY
syntax: typ = parser.STATUS_REPLY
syntax: typ = parser.BULK_REPLY
syntax: typ = parser.MULTI_BULK_REPLY
syntax: val = parser.null
This module is originally written for lua-nginx-module and redis2-nginx-module:
Although a lot of effort has been put into testing and code tuning, there must be some serious bugs lurking somewhere in this module. So whenever you are bitten by any quirks, please don't hesitate to
- create a ticket on the issue tracking interface provided by GitHub,
- or send a bug report or even patches to
[email protected].
Available on GitHub at agentzh/lua-redis-parser.
- Lua (http://www.lua.org/)
- or LuaJIT (http://www.luajit.org/)
- Latest source tarball of this library downloaded from https://github.com/agentzh/lua-redis-parser/tags
Gnu make and gcc is required to build this module.
gmake CC=gcc
gmake install CC=gcc make LDFLAGS='-bundle -undefined dynamic_lookup' CC=gcc
make installIf your Lua or LuaJIT is not installed into the system, specify its include directory like this:
make LUA_INCLUDE_DIR=/opt/luajit/include/luajit-2.0You can specify a custom path for the installation target:
make install LUA_LIB_DIR=/opt/lualibThe DESTDIR variable is also supported, to ease RPM packaging.
This library is included and enabled by default in the OpenResty bundle.
- Yichun "agentzh" Zhang (章亦春) [email protected]
This module is licenced under the BSD license.
Copyright (C) 2009-2017, by Yichun "agentzh" Zhang (章亦春) [email protected], OpenResty Inc.
All rights reserved.
Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
-
Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
-
Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
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