DBIx::Class::DigestColumns(3)

NAME
DBIx::Class::DigestColumns - Automatic digest columns

SYNOPSIS
In your DBIx::Class table class:

  __PACKAGE__->load_components(qw/DigestColumns ... Core/);

  #automatically generate a method "check_password" in result class
  __PACKAGE__->add_columns(
    'password' => {
      data_type => 'char',
      size      => 32,
      digest_check_method => 'check_password',
  }
  __PACKAGE__->digestcolumns(
      columns   => [qw/ password /],
      algorithm => 'MD5',
      encoding  => 'base64',
      dirty     => 1,
      auto      => 1,
  );

Note: The component needs to be loaded before Core.

Alternatively you could call each method individually

  __PACKAGE__->digest_columns(qw/ password /);
  __PACKAGE__->digest_algorithm('MD5');
  __PACKAGE__->digest_encoding('base64');
  __PACKAGE__->digest_dirty(1);
  __PACKAGE__->digest_auto(1);

DESCRIPTION
This DBIx::Class component can be used to automatically insert a message digest of selected columns. By default DigestColumns will use Digest::MD5 to insert a 128-bit hexadecimal message digest of the column value.

The length of the inserted string will be 32 and it will only contain characters from this set: '0'..'9' and 'a'..'f'.

If you would like to use a specific digest module to create your message digest, you can set "digest_algorithm":

  __PACKAGE__->digest_algorithm('SHA-1');

Options added to add_column

  digest_check_method => $method_name
By using the digest_check_method attribute when you declare a column you can create a check method for that column. The check method accepts a plain text string, performs the correct digest on it and returns a boolean value indicating whether this method matches the currently_stored value.

  $row->password('old_password');
  $row->update;
  $row->password('new_password');
  $row->check_password('new_password'); #returns true
  $row->check_password('old_password'); #returns false
  $row->update;

METHODS

  digestcolumns
  __PACKAGE__->digestcolumns(
      columns   => [qw/ password /],
      algorithm => $algorithm',
      encoding  => $encoding,
      dirty     => 1,
      auto      => 1,
  );

Calls "digest_columns", "digest_algorithm", and "digest_encoding" and "digest_auto" if the corresponding argument is defined.

  register_column
Override the original register_column to handle the creation of check methods.

  digest_columns
Takes a list of columns to be convert to a message digest during insert.

  __PACKAGE__->digest_columns(qw/ password /);

  digest_algorithm
Takes the name of a digest algorithm to be used to calculate the message digest.

  __PACKAGE__->digest_algorithm('SHA-1');

If a suitible digest module could not be loaded an exception will be thrown.

Supported digest algorithms are:

  MD5
  MD4
  MD2
  SHA-1
  SHA-256
  SHA-384
  SHA-512
  CRC-16
  CRC-32
  CRC-CCITT
  HMAC-SHA-1
  HMAC-MD5
  Whirlpool
  Adler-32

digest_algorithm defaults to "MD5".

  digest_encoding
Selects the encoding to use for the message digest.

  __PACKAGE__->digest_encoding('base64');

Possilbe encoding schemes are:

  binary
  hex
  base64

digest_encoding defaults to "hex".

  _get_digest_string $value
Handles the actual encoding of column values into digests. When given a $value it will return the digest string for that value. This is the method used by "_digest_column_values" So you can use it to create an identical digest if you need one for comparison (e.g. password authentication).

  _digest_column_values
Go through the columns and digest the values that need it.

This method is called by insert and update when automatic digests are turned on. If dirty is enabled it will only digest the values of dirtied columns.

  digest_auto
  __PACKAGE__->digest_auto(1);

Turns on and off automatic digest columns. When on, this feature makes all UPDATEs and INSERTs automatically insert a message digest of selected columns.

The default is for digest_auto is to be on.

  digest_dirty
  __PACKAGE__->digest_dirty(1);

Turns on and off the limiting of automatic digests to only dirty columns. When on, only columns that have been dirtied will have their values digested during UPDATEs and INSERTs. If auto is set to off this option does nothing.

The default is for digest_dirty is to be off to mantain compatibility with older versions of this module.

EXTENDED METHODS
The following DBIx::Class::Row methods are extended by this module:-

insert
update

SEE ALSO
DBIx::Class, Digest

AUTHOR
Tom Kirkpatrick (tkp) <tkp@cpan.org>

With contributions from Guillermo Roditi (groditi) <groditi@cpan.org> and Marc Mims <marc@questright.com>

LICENSE
You may distribute this code under the same terms as Perl itself.