aebe5a93dc
That completes the json_format() function for now. At least, it now does everything I had planned for it. Ended up at a bit over 300 LOC. That's larger than I had expected, but still alright.
88 lines
3 KiB
Text
88 lines
3 KiB
Text
=head1 NAME
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FU::Util - Miscellaneous utility functions that really should have been part of
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a core Perl installation but aren't for some reason because the Perl community
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doesn't believe in the concept of a "batteries included" standard library.
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</rant>
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=head1 SYNOPSIS
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use FU::Util qw/json_format/;
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my $data = json_format [1, 2, 3];
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=head1 DESCRIPTION
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=head2 JSON parsing & formatting
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This module comes with a custom C-based JSON parser and formatter. These
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functions conform strictly to L<RFC-8259|https://tools.ietf.org/html/rfc8259>,
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non-standard extensions are not supported and never will be. It also happens to
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be pretty fast, refer to L<FU::Benchmarks> for some numbers.
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JSON booleans are decoded into C<builtin::true> and C<builtin::false>. When
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formatting, those builtin constants are the I<only> recognized boolean values -
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alternative representations such as C<JSON::PP::true> and C<JSON::PP::false>
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are not recognized and attempting to format such values will croak.
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=over
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=item json_format($scalar, %options)
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Format a Perl value as JSON.
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With the default options, this function behaves roughly similar to:
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JSON::PP->new->allow_nonref->core_bools->convert_blessed->encode($scalar);
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This function croaks when attempting to format a floating point C<NaN> or
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C<Inf>.
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Some modules escape the slash character in encoded strings to prevent a
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potential XSS vulnerability when embedding JSON inside C<< <script> ..
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</script> >> tags. This function does I<not> do that because it might not even
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be sufficient. The following is probably an improvement:
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json_format($data) =~ s{</}{<\\/}rg =~ s/<!--/<\\u0021--/rg;
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The following C<%options> are supported:
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=over
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=item canonical
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Boolean, write hash keys in deterministic (sorted) order. This option currently
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has no effect on tied hashes.
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=item pretty
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Boolean, format JSON with newlines and indentation for easier reading. Beauty
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is in the eye of the beholder, this option currently follows the convention
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used by L<JSON::XS> and others: 3 space indent and one space around the C<:>
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separating object keys and values. The exact format might change in later
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versions.
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=item utf8
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Boolean, returns a UTF-8 encoded byte string instead of a Perl Unicode string.
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=item max_size
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Maximum permitted size, in bytes, of the generated JSON string. Defaults to 1 GiB.
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=item max_depth
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Maximum permitted nesting depth of Perl values. Defaults to 512.
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=back
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=back
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(Why the hell yet another JSON codec when CPAN is already full of them!? Well,
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L<JSON::XS> is pretty cool but isn't going to be updated to support Perl's new
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builtin booleans. L<JSON::PP> is slow and while L<Cpanel::JSON::XS> is
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perfectly adequate, its codebase is a little too messy for my taste - too many
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unnecessary features and C<#ifdef>s to support ancient perls and esoteric
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configurations. Still, if you need anything not provided by these functions,
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L<JSON::PP> and L<Cpanel::JSON::XS> are perfectly fine alternatives.
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L<JSON::SIMD> and L<Mojo::JSON> also look like good and maintained candidates.)
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