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CGI::Compress::Gzip::FileHandle(3pm) User Contributed Perl Documentation CGI::Compress::Gzip::FileHandle(3pm)


CGI::Compress::Gzip::FileHandle - CGI::Compress::Gzip helper package


Copyright 2006-2007 Clotho Advanced Media, Inc., <>

Copyright 2007-2008 Chris Dolan <>

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.


   use CGI::Compress::Gzip;
   my $cgi = new CGI::Compress::Gzip;
   print $cgi->header();
   print "<html> ...";


This is intended for internal use only! Use CGI::Compress::Gzip instead.

This CGI::Compress::Gzip helper class subclasses IO::Zlib. It is is needed to make sure that output is not compressed until the CGI header is emitted. This filehandle delays the ignition of the zlib filter until it sees the exact same header generated by CGI::Compress::Gzip::header() pass through it's WRITE() method. If you change the header before printing it, this class will throw an exception.

This class holds one global variable representing the previous default filehandle used before the gzip filter is put in place. This filehandle, usually STDOUT, is replaced after the gzip stream finishes (which is usually when the CGI object goes out of scope and is destroyed).


Overrides IO::Zlib::OPEN. This method doesn't actually do anything -- it just stores it's arguments for a later call to SUPER::OPEN in WRITE(). The reason is that we may not have seen the header yet, so we don't yet know whether to compress output.
Emit the uncompressed header followed by the compressed body.
Flush the compressed output.


Clotho Advanced Media,

Primary developer: Chris Dolan

2022-06-09 perl v5.34.0