ngx.re - Lua API for convenience utilities for ngx.re.
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This Lua module is production ready.
local ngx_re = require "ngx.re"
-- split
local res, err = ngx_re.split("a,b,c,d", ",")
--> res is now {"a", "b", "c", "d"}
-- opt
ngx_re.opt("jit_stack_size", 128 * 1024)
--> the PCRE jit stack can now handle more complex regular expressionsThis Lua module provides a Lua API which implements convenience utilities for
the ngx.re API.
All the methods of this module are static (or module-level). That is, you do not need an object (or instance) to call these methods.
syntax: res, err = ngx_re.split(subject, regex, options?, ctx?, max?, res?)
Splits the subject string using the Perl compatible regular expression
regex with the optional options.
This function returns a Lua (array) table (with integer keys) containing the split values.
In case of error, nil will be returned as well as a string describing the
error.
When regex contains a sub-match capturing group, and when such a match is
found, the first submatch capture will be inserted in between each split
value, like so:
local ngx_re = require "ngx.re"
local res, err = ngx_re.split("a,b,c,d", "(,)")
-- res is now {"a", ",", "b", ",", "c", ",", "d"}When regex is empty string "", the subject will be split into chars,
like so:
local ngx_re = require "ngx.re"
local res, err = ngx_re.split("abcd", "")
-- res is now {"a", "b", "c", "d"}The optional ctx table argument can be a Lua table holding an optional pos
field. When the pos field in the ctx table argument is specified,
ngx_re.split will start splitting the subject from that index:
local ngx_re = require "ngx.re"
local res, err = ngx_re.split("a,b,c,d", ",", nil, {pos = 5})
-- res is now {"c", "d"}The optional max argument is a number that when specified, will prevent
ngx_re.split from adding more than max matches to the res array:
local ngx_re = require "ngx.re"
local res, err = ngx_re.split("a,b,c,d", ",", nil, nil, 3)
-- res is now {"a", "b", "c,d"}Specifying max <= 0 disables this behavior, meaning that the number of
results won't be limited.
The optional 6th argument res can be a table that ngx_re.split will re-use
to hold the results instead of creating a new one, which can improve
performance in hot code paths. It is used like so:
local ngx_re = require "ngx.re"
local my_table = {"hello world"}
local res, err = ngx_re.split("a,b,c,d", ",", nil, nil, nil, my_table)
-- res/my_table is now {"a", "b", "c", "d"}When provided with a res table, ngx_re.split won't clear the table
for performance reasons, but will rather insert a trailing nil value
when the split is completed:
local ngx_re = require "ngx.re"
local my_table = {"W", "X", "Y", "Z"}
local res, err = ngx_re.split("a,b", ",", nil, nil, nil, my_table)
-- res/my_table is now {"a", "b", nil, "Z"}When the trailing nil is not enough for your purpose, you should
clear the table yourself before feeding it into the split function.
syntax: ngx_re.opt(option, value)
Allows changing of regex settings. Currently, it can only change the
jit_stack_size of the PCRE engine, like so:
init_by_lua_block { require "ngx.re".opt("jit_stack_size", 200 * 1024) }
server {
location /re {
content_by_lua_block {
-- full regex and string are taken from https://github.com/JuliaLang/julia/issues/8278
local very_long_string = [[71.163.72.113 - - [30/Jul/2014:16:40:55 -0700] ...]]
local very_complicated_regex = [[([\d\.]+) ([\w.-]+) ([\w.-]+) (\[.+\]) ...]]
local from, to, err = ngx.re.find(very_long_string, very_complicated_regex, "jo")
-- with the regular jit_stack_size, we would get the error 'pcre_exec() failed: -27'
-- instead, we get a match
ngx.print(from .. "-" .. to) -- prints '1-1563'
}
}
}The jit_stack_size cannot be set to a value lower than PCRE's default of 32K.
This method requires the PCRE library enabled in Nginx.
This feature was first introduced in the v0.1.12 release.
The openresty-en mailing list is for English speakers.
The openresty mailing list is for Chinese speakers.
Please report bugs or submit patches by
- creating a ticket on the GitHub Issue Tracker,
- or posting to the OpenResty community.
Thibault Charbonnier - (@thibaultcha)
This module is licensed under the BSD license.
Copyright (C) 2016-2017, by Yichun "agentzh" Zhang, 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.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- the lua-resty-core library.
- the ngx_lua module: https://github.com/openresty/lua-nginx-module
- OpenResty: https://openresty.org