lua-resty-random

lua-resty-random is a random library for OpenResty.

This library works only in OpenResty (or Nginx with Lua module) that has OpenSSL support.

Hello World with lua-resty-random

    local random = require "resty.random"
    -- Get two random bytes
    local bytes = random.bytes(2)
    -- Get two random bytes hexadecimal encoded
    local hxbts = random.bytes(2, 'hex')
    -- Get random number
    local numbr = random.number(1, 10)
    -- Get random token (by default uses A-Z, a-z, and 0-9 chars)
    local token = random.token(10)

About The Internals

For random bytes lua-resty-random uses OpenSSL RAND_bytes that is included in OpenResty (or Nginx) when compiled with OpenSSL. For random numbers the library uses Lua's math.random, and math.randomseed. You should note that on LuaJIT environment, LuaJIT uses a Tausworthe PRNG with period 2^223 to implement math.random and math.randomseed. Hexadecimal dumps are implemented using ngx_hex_dump.

Lua API

string random.bytes(len, format)

Returns len number of random bytes using OpenSSL RAND_bytes. You may optionally pass "hex" as format argument if you want random bytes hexadecimal encoded.

Example

    local random = require "resty.random"
    print(random.bytes(10))
    print(random.bytes(10, "hex")

number random.number(min, max, reseed)

Returns random number between min and max (including min and max). You may optionally pass true as reseed argument if you want to reseend random number generator (normally not needed, and random number generator is seeded once when you do require "resty.random".

Example

    local random = require "resty.random"
    print(random.number(1, 10))
    print(random.number(1, 10, true))

string random.token(len, chars, sep)

Returns random token consisting of chars (by default it uses A-Z, a-z, and 0-9 as chars). You may also pass a string as a separator with sep argument.

Example

    local random = require "resty.random"
    print(random.token(10))
    print(random.token(10, "ABCD"))
    print(random.token(10, { "A", "B", "C", "D" }))
    print(random.token(10, { "Ford", "Audi", "Mustang", "A6" }, " "))

License

lua-resty-random uses two clause BSD license.

    Copyright (c) 2013, Aapo Talvensaari
    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.