Bio::Graphics::Browser2::GFFhelper -- Helps gbrowse plugins handle GFF

       Email smckay@bcgsc.bc.ca

       This package and its accompanying libraries is free software; you can redistribute it and/or modify it
       under the terms of the GPL (either version 1, or at your option, any later version) or the Artistic
       License 2.0.  Refer to LICENSE for the full license text. In addition, please see DISCLAIMER.txt for
       disclaimers of warranty.

perl v5.40.0                                       2024-10-20             Bio::Graphics::...ser2::GFFhelper(3pm)

       This modules helps process GFF prior to loading into the database and provides rollback capability for
       feature editors/loaders

   GFFhelp
       This module deals with the different GFF2 dialects and changes them to GFF3 format. It also allows
       conversion of Bio::DB::GFF::Feature objects to Bio::SeqFeature::Generic objects, which is required for
       consistent feature and attribute handling across different input/output formats.

   SequenceExtraction
       If DNA is appended to the GFF, it will be extracted.  The read_gff method returns a string containing
       processed GFF and also a sequence string.

   Rollbacks
       The state of a segment can be captured and saved in case the user wishes to revert to an earlier version
       of the segment after editing/deleting features.  The last 10 modified segments are saved in a round-robin
       rotation.  In plugins that inherit methods from this module, the $ROLLBACK variable must be defined with
       a string containing the path to a directory where the web user ('apache', 'nobody', etc.) has write
       access.  If $ROLLBACK is undefined, the rollback functionality is disabled.

       See the GMOD website for information on bug submission http://www.gmod.org

       Bio::Graphics::Browser2::GFFhelper -- Helps gbrowse plugins handle GFF

         package Bio::Graphics::Browser2::Plugin::MyPlugin;

         use vars qw/@ISA $ROLLBACK/;

         @ISA = qw/ Bio::Graphics::Browser2::Plugin
                    Bio::Graphics::Browser2::GFFhelper /;

         $ROLLBACK = '/tmp/';

         # other plugin subs skipped...

         sub save_segment {
           my ($self, $segment) = @_;
           return 0 unless $ROLLBACK;
           $self->{rb_loc} ||= $ROLLBACK;
           $self->save_state($segment);
           1;
         }

         sub gff_from_rollback {
           my $self = shift;
           my $conf = $self->configuration;

           # don't save a persistent rb_id, look for a CGI param each time
           my $rollback = $self->config_param('rb_id');

           my $gff = $self->rollback($rollback);

           # this is a rollback to an earlier version of an existing segment
           # we don't need DNA, just the GFF
           $gff;
         }

         # read GFF2 dialects
         sub gff {
           my $self = shift;
           my $gff  = shift;

           # set a flag to add a header to the GFF
           $self->{header} = 1;

           # set sequence name in case the GFF does not have it
           $self->refseq('L16622');

           # process the GFF, convert it to GFF3, get the sequence
           my ($newGFF, $dna) = $self->read_gff($gff);
           return ($newGFF, $dna);
         }