Re^2: Outputting JSON with sorted names/keys

Thanks! By using Tie::Hash::MultiValueOrdered to create the initial hash, and then JSON::MultiValueOrdered to serialize it into JSON, the serialized output was in the right order.

use warnings;
use strict;
use autodie;
use JSON;
use Data::Dumper;
use 5.010;

my @order = qw/id disp ver auth/;

my $dat = [ ({ id => 'a', disp => 'a', ver => 'a', auth => 'a' })x2 ];
+ # dummy data

local $\ = "\n";

print 'Unsorted => ', JSON->new->indent->space_after->encode( $dat );
print 'Alpha Sorted => ', JSON->new->indent->space_after->canonical->e
+ncode( $dat );
print 'My Order => ', my $pryrtstr = manual_ordered_json( $dat, \@orde
+r );

{
    # [tobyink][id://11111911]
    use JSON::MultiValueOrdered;
    use Tie::Hash::MultiValueOrdered;
    my $tied = tie my %hash, 'Tie::Hash::MultiValueOrdered';
    $hash{id} = 'a';
    $hash{disp} = 'a';
    $hash{ver} = 'a';
    $hash{auth} = 'a';

    #my $d2 = [ {%hash}, {%hash} ];     # didn't maintain order -- oh,
+ right, because that made a normal hashref from an ordered hash; duh!
    my $d2 = [ \%hash, \%hash ];        # does maintain order

    print 'tobyink => ', my $tobyinkstr = JSON::MultiValueOrdered->new
+(pretty=>1)->encode($d2);

    use Test::More tests => 1;
    $tobyinkstr =~ s/\s//g;
    $pryrtstr =~ s/\s//g;
    is_deeply $tobyinkstr, $pryrtstr, 'serialization match';
    done_testing;

}


sub manual_ordered_json{
    my @list = @{$_[0]};
    my @ordr = @{$_[1]};
    my $out = "[\n";
    for my $i ( 0 .. $#list ) {
        my $h = $list[$i];
        $out .= "    {\n";
        for my $j ( 0 .. $#ordr ) {
            my $k = $ordr[$j];
            next unless defined $k;
            next unless exists $h->{$k};
            $out .= sprintf qq|        "%s": "%s"|, $k, $h->{$k} // '<
+undef>';
            $out .= ',' if $j < $#ordr;
            $out .= "\n";
        }
        $out .= "    }";
        $out .= "," if $i < $#list;
        $out .= "\n";
    }
    $out .= "]\n";
    return $out;
}
[download]

(As you can tell from my commented-out line, I had a brain failure in my first attempt, and converted the ordered hash into a plain hashref, thus losing the original order. Once I realized that, I got it working.)

Comment on Re^2: Outputting JSON with sorted names/keys Download Code

Replies are listed 'Best First'.
Re^3: Outputting JSON with sorted names/keys by tobyink (Canon) on Jan 27, 2020 at 09:07 UTC
You may find a wrapper like this helpful: `sub h { tie my %hash, 'Tie::Hash::MultiValueOrdered'; while (my ($k, $v) = splice @_, 0, 2) { $hash{$k} = $v; } \%hash; }` [download] That way you can build your data structure pretty naturally, just using `h(...)` for a hashref instead of `{...}`: `my $people = [ h( name => "Alice", age => 21 ), h( name => "Bob", name => "Robert", age => 22 ), ]; print JSON::MultiValueOrdered->new(pretty=>1)->encode($people);` [download] toby döt ink	[reply] [d/l] [select]
Re^4: Outputting JSON with sorted names/keys by pryrt (Abbot) on Jan 27, 2020 at 14:12 UTC
>You may find a wrapper like this helpful Ooh, that is nice. I'd even recommend adding it to the POD or the `examples/` folder (or both) of the JSON-MultiValueOrdered distro.	[reply] [d/l]


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