SYNOPSIS
use String::Random;
my $string_gen = String::Random->new;
print $string_gen->randregex('\d\d\d'); # Prints 3 random digits
# Prints 3 random printable characters
print $string_gen->randpattern("...");
or
use String::Random qw(random_regex random_string); print random_regex('\d\d\d'); # Also prints 3 random digits print random_string("..."); # Also prints 3 random printable characters
DESCRIPTION
This module makes it trivial to generate random strings.As an example, let's say you are writing a script that needs to generate a random password for a user. The relevant code might look something like this:
use String::Random; my $pass = String::Random->new; print "Your password is ", $pass->randpattern("CCcc!ccn"), "\n";
This would output something like this:
Your password is UDwp$tj5
NOTE!!!: currently, String::Random uses Perl's built-in predictable random number generator so the passwords generated by it are insecure.
If you are more comfortable dealing with regular expressions, the following code would have a similar result:
use String::Random; my $pass = String::Random->new; print "Your password is ", $pass->randregex('[A-Z]{2}[a-z]{2}.[a-z]{2}\d'), "\n";
Patterns
The pre-defined patterns (for use with "randpattern()" and "random_pattern()") are as follows:
c Any Latin lowercase character [a-z] C Any Latin uppercase character [A-Z] n Any digit [0-9] ! A punctuation character [~`!@$%^&*()-_+={}[]|\:;"'.<>?/#,] . Any of the above s A "salt" character [A-Za-z0-9./] b Any binary data
These can be modified, but if you need a different pattern it is better to create another pattern, possibly using one of the pre-defined as a base. For example, if you wanted a pattern "A" that contained all upper and lower case letters ("[A-Za-z]"), the following would work:
my $gen = String::Random->new; $gen->{'A'} = [ 'A'..'Z', 'a'..'z' ];
or
my $gen = String::Random->new; $gen->{'A'} = [ @{$gen->{'C'}}, @{$gen->{'c'}} ];
The random_string function, described below, has an alternative interface for adding patterns.
Methods
- new
- new max => number
- new rand_gen => sub
-
Create a new String::Random object.
Optionally a parameter "max" can be included to specify the maximum number of characters to return for "*" and other regular expression patterns that do not return a fixed number of characters.
Optionally a parameter "rand_gen" can be included to specify a subroutine coderef for generating the random numbers used in this module. The coderef must accept one argument "max" and return an integer between 0 and "max - 1". The default rand_gen coderef is
sub { my ($max) = @_; return int rand $max; }
- randpattern LIST
-
The randpattern method returns a random string based on the concatenation
of all the pattern strings in the list.
It will return a list of random strings corresponding to the pattern strings when used in list context.
- randregex LIST
-
The randregex method returns a random string that will match the regular
expression passed in the list argument.
Please note that the arguments to randregex are not real regular expressions. Only a small subset of regular expression syntax is actually supported. So far, the following regular expression elements are supported:
\w Alphanumeric + "_". \d Digits. \W Printable characters other than those in \w. \D Printable characters other than those in \d. . Printable characters. [] Character classes. {} Repetition. * Same as {0,}. ? Same as {0,1}. + Same as {1,}.
Regular expression support is still somewhat incomplete. Currently special characters inside [] are not supported (with the exception of ``-'' to denote ranges of characters). The parser doesn't care for spaces in the ``regular expression'' either.
Functions
- random_string PATTERN,LIST
- random_string PATTERN
-
When called with a single scalar argument, random_string returns a random
string using that scalar as a pattern. Optionally, references to lists
containing other patterns can be passed to the function. Those lists will
be used for 0 through 9 in the pattern (meaning the maximum number of lists
that can be passed is 10). For example, the following code:
print random_string("0101", ["a", "b", "c"], ["d", "e", "f"]), "\n";
would print something like this:
cebd
BUGS
This is Bug FreeX code. (At least until somebody finds oneX)Please report bugs here:
<https://rt.cpan.org/Public/Dist/Display.html?Name=String-Random> .
AUTHOR
Original Author: Steven Pritchard "[email protected]"Now maintained by: Shlomi Fish ( <http://www.shlomifish.org/> ).