PerlIO::via::MD5 - PerlIO layer for creating an MD5 digest of a file

 use PerlIO::via::MD5;

 PerlIO::via::MD5->method( 'hexdigest' ); # default, return 32 hex digits
 PerlIO::via::MD5->method( 'digest' );    # return 16-byte binary value
 PerlIO::via::MD5->method( 'b64digest' ); # return 22-byte base64 (MIME) value

 open( my $in,'<:via(MD5)','file' )
  or die "Can't open file for digesting: $!\n";
 my $digest = <$in>;

This module implements a PerlIO layer that can only read files and return an MD5 digest of the contents of the file.

There is one class method.

 $method = PerlIO::via::MD5->method;  # obtain current setting
 PerlIO::via::MD5->method( $method ); # set new digest method

Calling this class method with a new value will cause all subsequently opened files to assume that new setting. The method however is remembered within the layer, so that it becomes part of the information that is associated with that file.

If it were possible to pass parameters such as this to the layer while opening the file, that would have been the approach taken. Since that is not possible yet, this way of doing it seems to be the next best thing.

 Digest::MD5 (any)

PerlIO::via, Digest::MD5, PerlIO::via::StripHTML, PerlIO::via::QuotedPrint, PerlIO::via::Base64, PerlIO::via::Rotate.

Copyright (c) 2002-2003 Elizabeth Mattijsen. All rights reserved. This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.