json2tsv.pl

#!/usr/bin/perl

=head1 USAGE

  cat data.json-lines | ./json2tsv.pl

Reads individual lines which *each* contain a separate json structure
and saves the data in TSV format.

This is useful to save data from MongoDB find() statement using
cut'n'paste.

=cut

use strict;

use Data::Dumper;
$Data::Dumper::Indent= 1;
use JSON;
use Util::tsv;

my $tsv_fnm= 'data.tsv';
my @column_names;

my @PARS;
my $arg;
while (defined ($arg= shift (@ARGV)))
{
  if ($arg eq '--') { push (@PARS, @ARGV); @ARGV= (); }
  elsif ($arg =~ /^--(.+)/)
  {
    my ($opt, $val)= split ('=', $1, 2);

       if ($opt eq 'help') { usage(); }
    elsif ($opt eq 'out') { $tsv_fnm= $val || shift (@ARGV); }
    elsif ($opt eq 'col')
    {
      $val= shift (@ARGV) unless ($val);
      push (@column_names, split (',', $val));
    }
    else { usage(); }
  }
  elsif ($arg =~ /^-(.+)/)
  {
    foreach my $opt (split ('', $1))
    {
         if ($opt eq 'h') { usage(); exit (0); }
      # elsif ($opt eq 'x') { $x_flag= 1; }
      else { usage(); }
    }
  }
  else
  {
    push (@PARS, $arg);
  }
}

my @rows;
my %cols;

if (@PARS)
{
  foreach my $fnm (@PARS)
  {
    if (open (FI, '<:utf8', $fnm))
    {
      parse_stream(*FI, \@rows, \%cols);
      close (FI);
    } # TODO: else complain
  }