.. _library_ids:

ids

This library generates random identifiers given the number of bytes of randomness. The identifiers are Base64 encoded. By default, 20 bytes (160 bits) are used.

The generation of random identifiers uses the /dev/urandom random number generator when available. This includes macOS, Linux, \*BSD, and other POSIX operating-systems. On Windows, a pseudo-random generator is used but randomized using the current wall time.

Identifiers can be generated as atoms, lists of characters, or lists of character codes.

See also the uuid and ulid libraries.

API documentation

Open the `../../docs/library_index.html#ids <../../docs/library_index.html#ids>`__ link in a web browser.

Loading

To load all entities in this library, load the loader.lgt file:

::

| ?- logtalk_load(ids(loader)).

Testing

To test this library predicates, load the tester.lgt file:

::

| ?- logtalk_load(ids(tester)).

Usage

To generate an identifier using the default 160 bits of randomness:

::

| ?- ids::generate(Identifier). Identifier = '2gpMzqAFXBO5mYFIPX1qMkHxgGE=' yes

To generate an identifier represented by an atom using 240 bits (30 bytes) of randomness:

::

| ?- ids(atom, 30)::generate(Identifier). Identifier = 'ie/jYcLsqo8ZguCOF1ZNPFDRvJ03Ww5Qa9e0FxRB' yes

To generate an identifier represented by a list of characters using 64 bits (8 bytes) of randomness:

::

| ?- ids(chars, 8)::generate(Identifier). Identifier = ['5','0','8','V',d,'S',c,y,n,o,'A',=] yes

To generate an identifier represented by a list of character codes using 64 bits (8 bytes) of randomness:

::

| ?- ids(codes, 8)::generate(Identifier). Identifier = [111,81,86,55,99,79,70,77,65,74,103,61] yes