#!/usr/bin/perl -w # (C) Copyright 2010-2016 MET Norway # # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, but # WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU # General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program; if not, write to the Free Software # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA # 02110-1301, USA. # pod included at end of file use strict; use Getopt::Long; use Pod::Usage qw(pod2usage); use Geo::BUFR; # Parse command line options my %option = (); GetOptions( \%option, 'ahl=s', # Extract BUFR messages with AHL matching <ahl_regexp> only 'help', # Print help information and exit 'only_ahl', # Extract AHLs only 'outfile=s', # Print to file instead of STDOUT 'reuse_ahl=i', # Reuse last AHL if current BUFR message has no AHL 'verbose=i', # Set verbose level to n, 0<=n<=6 (default 0) 'without_ahl', # Print the BUFR messages only, skipping AHLs ) or pod2usage(-verbose => 0); # User asked for help pod2usage(-verbose => 1) if $option{help}; # only_ahl and without_ahl are mutually exclusive pod2usage( -message => "Options only_ahl and without_ahl are mutually exclusive", -exitval => 2, -verbose => 0) if $option{only_ahl} && $option{without_ahl}; # Make sure there is at least one input file pod2usage(-verbose => 0) unless @ARGV; # Set verbosity level Geo::BUFR->set_verbose($option{verbose}) if $option{verbose}; # Set whether last ahl should be reused if current BUFR message has no AHL Geo::BUFR->reuse_current_ahl($option{reuse_ahl}) if defined $option{reuse_ahl}; my $ahl_regexp; if ($option{ahl}) { eval { $ahl_regexp = qr/$option{ahl}/ }; die "Argument to --ahl is not a valid Perl regular expression: $@" if $@; } # Where to direct output (including verbose output, but not output to STDERR) my $OUT; if ($option{outfile}) { open($OUT, '>', $option{outfile}) or die "Cannot open $option{outfile} for writing: $!"; } else { $OUT = *STDOUT; } binmode($OUT); # No need to decode section 4 here Geo::BUFR->set_nodata(1); # Loop for processing of BUFR input files foreach my $inputfname ( @ARGV ) { my $bufr = Geo::BUFR->new(); $bufr->set_filter_cb(\&filter_on_ahl,$ahl_regexp) if $option{ahl}; # Open BUFR file $bufr->fopen($inputfname); # Process input file extract($bufr); $bufr->fclose(); } # Extract BUFR messages and/or AHLs from BUFR file sub extract { my $bufr = shift; # BUFR object my ($current_message_number, $current_ahl); READLOOP: while (not $bufr->eof()) { # Read next observation. If an error is encountered during # decoding, skip this observation while printing the error # message to STDERR, also displaying ahl of bulletin if found # (but skip error message if the message should be skipped on # --ahl anyway). eval { $bufr->next_observation(); }; if ($@) { $current_ahl = $bufr->get_current_ahl() || ''; next READLOOP if $option{ahl} && $current_ahl !~ $ahl_regexp; warn $@; # Try to extract message number and ahl of the bulletin # where the error occurred $current_message_number = $bufr->get_current_message_number(); if (defined $current_message_number) { my $error_msg = "In message $current_message_number"; $error_msg .= " contained in bulletin with ahl $current_ahl\n" if $current_ahl; warn $error_msg if $error_msg; } next READLOOP; } next if $option{ahl} && $bufr->is_filtered(); # Skip messages where stated length of BUFR message is sure to # be erroneous, unless we want ahls only (or should we skip # message in this case also? Hard choice...) next if !$option{only_ahl} && $bufr->bad_bufrlength(); my $current_subset_number = $bufr->get_current_subset_number(); # If next_observation() did find a BUFR message, subset number # should have been set to at least 1 (even in a 0 subset message) last READLOOP if $current_subset_number == 0; $current_message_number = $bufr->get_current_message_number(); $current_ahl = $bufr->get_current_ahl() || ''; if ($current_ahl && !$bufr->ahl_is_reused()) { if ($option{only_ahl}) { print $OUT $current_ahl, "\n"; } elsif (!$option{without_ahl}) { # Use \r\r\n after AHL, since this is the standard # sequence used in GTS bulletins print $OUT $current_ahl . "\r\r\n"; } } next READLOOP if $option{only_ahl}; my $msg = $bufr->get_bufr_message(); print $OUT $msg; } } # Filter routines sub filter_on_ahl { my $bufr = shift; my $ahl_regexp = shift; my $ahl = $bufr->get_current_ahl() || ''; return $ahl =~ $ahl_regexp ? 0 : 1; } =pod =encoding utf8 =head1 SYNOPSIS bufrextract.pl <bufr file(s)> [--ahl <ahl_regexp>] [--only_ahl] | [--without_ahl] [--outfile <filename>] [--reuse_ahl n] [--help] [--verbose n] =head1 DESCRIPTION Extract all BUFR messages and/or corresponding AHLs from BUFR file(s), possibly filtering on AHL. The AHL (Abbreviated Header Line) is recognized as the TTAAii CCCC DTG [BBB] immediately preceding the BUFR message. Execute without arguments for Usage, with option C<--help> for some additional info. See also L<https://wiki.met.no/bufr.pm/start> for examples of use. =head1 OPTIONS --ahl <ahl_regexp> Extract BUFR messages and/or AHLs with AHL matching <ahl_regexp> only --only_ahl Extract AHLs only --without_ahl Extract BUFR messages only --outfile <filename> Will print to <filename> instead of STDOUT --reuse_ahl n n=0 (default) AHL is considered belonging to a BUFR message only if immediately preceding n=1 When filtering using --ahl: Reuse last AHL found if current BUFR message has no immediately preceding AHL --help Display Usage and explain the options used. For even more info you might prefer to consult perldoc bufrextract.pl --verbose n Set verbose level to n, 0<=n<=6 (default 0) Options may be abbreviated, e.g. C<--h> or C<-h> for C<--help>. For option C<--ahl> the <ahl_regexp> should be a Perl regular expression. E.g. C<--ahl 'ISS... ENMI'> will decode only BUFR SHIP (ISS) from CCCC=ENMI. If the BUFR file(s) are known to consist solely of GTS bulletins, you might consider setting C<--reuse 1> when applying C<--ahl>, in order to extract all (and not only the first) BUFR messages in multi message bulletins. Such bulletins are very rare nowadays, however, and see also the L</"CAVEAT"> for more on this option. Note that the corresponding AHL is still extracted (and printed) only once. No bufrtables are needed for running bufrextract.pl, since section 4 in BUFR message will not be decoded (which also speeds up execution quite a bit). =head1 HINTS With a little knowledge of Perl you could easily extend bufrextract.pl to extract BUFR messages based on whatever information is available in section 0-3, by making your own copy of bufrextract.pl and then employing one of the many C<get_> subroutines in BUFR.pm. For example, to extract only BUFR messages with data category 1, add the following line just before calling C<is_filtered()> in code: next if $bufr->get_data_category() != 1; Or to extract BUFR messages with TM315009 only: next if bufr->get_descriptors_unexpanded() ne '315009'; =head1 CAVEAT Sometimes GTS bulletins are erroneously issued with extra characters between the GTS AHL and the start of BUFR message (besides the standard character sequence CRCRLF), likely leading bufrextract.pl to miss the AHL. Also, if applying C<--reuse 1>, the BUFR message of such a GTS bulletin will then be wrongly associated with the AHL of the previous GTS bulletin when filtering on AHL. If bulletins with this kind of error is more of a concern than multi message bulletins, you should probably refrain from making use of the C<--reuse 1> option. =head1 AUTHOR Pål Sannes E<lt>pal.sannes@met.noE<gt> =head1 COPYRIGHT Copyright (C) 2010-2016 MET Norway =cut