CUID

CUID generator for Lua.

For more information, see: http://usecuid.org

Installation

If available on LuaRocks:

$ luarocks --local install cuid

Otherwise, you could install through this root project directory:

$ luarocks --local make

Usage

To load this library, just type:

local cuid = require ("cuid")

Once loaded, you can generate fresh CUIDs through:

local id = cuid.generate ( )

As an example of CUID, we have c00p6qup20000ckkzslahp5pn, where:

• c is the CUID prefix (so it’s a valid variable).
• 00p6qup2 is a timestamp/continuous number.
• 0000 is the internal sequential counter.
• ckkz is the machine/host fingerprint.
• slahp5pn are pseudo-random numbers.

To generate slugs (shorter and collision-weak CUIDs), just type the following:

local slug = cuid.slug ( )

Slugs are made of 8 characters, and there’s no prefix (as is the case of CUIDs - “c” in the case). So, slugs are often used as suffixes, for instance, on URLs.

Configuration

You could as well set a custom fingerprint for CUID generation by an environment variable. This environment variable is called LUA_CUID_FINGERPRINT.

Whenever the cuid library is loaded, it will lookup such environment variable to generate a fingerprint if it is indeed defined.

It’s also possible to set a custom fingerprint prior CUID/slug generation, just type the following for both cases:

local cuid = require 'cuid'

local fingerprint_input = "It's me, Mario!"

local id   = cuid.generate (fingerprint_input)
local slug = cuid.slug (fingerprint_input)

Such fingerprint text is used only once per function call, that is, on the next function call, everything remains the same of previous state prior custom fingerprint’s function call.

Credits

• Eric Elliott (author of the spec & maintainer of the original JS implementation)

Remarks

Pull requests and issues are welcome! Happy hacking!