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lib/Algorithm/CouponCode.pm  view on Meta::CPAN

=item *

The 4th character of each part is a checkdigit, so client-side scripting can
be used to highlight parts which have been mis-typed, before the code is even
submitted to the application's back-end validation.

=item *

The checkdigit algorithm takes into account the position of the part being
keyed.  So for example '1K7Q' might be valid in the first part but not in the
second so if a user typed the parts in the wrong boxes then their error could
be highlighted.

=item *

The code generation algorithm avoids 'undesirable' codes. For example any code
in which transposed characters happen to result in a valid checkdigit will be
skipped.  Any generated part which happens to spell an 'inappropriate' 4-letter
word (e.g.: 'P00P') will also be skipped.

=back

The Algorithm-CouponCode distribution includes a Javascript implementation of
the validator function, in the form of a jQuery plugin.  You can include this
in your web application to do client-side validation and highlighting of
errors.

I<Note> the cc_validate function and the Javascript plugin only validate that
the code is 'well-formed' (i.e.: each part has a valid checkdigit).  Checking
whether the code is in fact 'valid' is left up to your application and would
typically involve looking for the code in a database.  If you use the
Javascript plugin, you might choose to tweak the CSS to keep the red
highlighting of checksum errors but remove the green highlighting which might
imply the code was correct.

=head2 Randomness and Uniqueness

The code returned by C<cc_generate()> is random, but not necessarily unique.
If your application requires unique codes, it is your responsibility to
avoid duplicates (for example by using a unique index on your database column).

The codes are generated using a SHA1 cryptographic hash of a plaintext.  If you
do not supply a plaintext, one will be generated for you (using /dev/urandom if

lib/Algorithm/CouponCode.pm  view on Meta::CPAN

You can supply a regular expression for matching 4-letter words which should
not appear in generated output.  The C<make_bad_regex()> helper function can
be used to turn a list of words into a suitable regular expression.

=back

=head2 cc_validate( options )

Takes a code, cleans it up and validates the checkdigits.  Returns the
normalised (and untainted) version of the code on success or undef on error.
The following named parameters may be supplied:

=over 4

=item code

The code to be validated.  The parameter is mandatory.

=item parts