NAME

Mojo::JSON::MaybeXS - use JSON::MaybeXS as the JSON encoder for Mojolicious

SYNOPSIS

 use Mojo::JSON::MaybeXS;
 use Mojo::JSON qw/encode_json decode_json true false/;
 
 # Preload for scripts using Mojo::JSON
 $ perl -MMojo::JSON::MaybeXS $(which morbo) myapp.pl
 
 # Must be set in environment for hypnotoad
 $ PERL5OPT=-MMojo::JSON::MaybeXS hypnotoad myapp.pl

DESCRIPTION

Mojo::JSON::MaybeXS is a monkey-patch module for using JSON::MaybeXS as the JSON encoder for a Mojolicious application, or anything else using Mojo::JSON. It must be loaded before Mojo::JSON so the new functions will be properly exported.

CAVEATS

JSON::MaybeXS may load different modules behind the scenes depending on what is available, and these modules have slightly different behavior from Mojo::JSON and occasionally from each other. References to the behavior of JSON::MaybeXS below are actually describing the behavior shared among the modules it loads.

JSON::MaybeXS is used with the options allow_nonref, allow_unknown, allow_blessed, and convert_blessed. allow_nonref allows encoding and decoding of bare values outside of hash/array references, since Mojo::JSON does not prevent this, in accordance with RFC 7159. The other options prevent the encoder from blowing up when encountering values that cannot be represented in JSON to better match the behavior of Mojo::JSON; in most cases, where Mojo::JSON would stringify a reference, JSON::MaybeXS with these settings will encode it to null. See below for more specifics.

If Cpanel::JSON::XS version 3.0112 or greater is loaded, it will be used with the option stringify_infnan as well, to match the behavior of Mojo::JSON.

As of this writing, the author has found the following incompatibilities:

Object Conversion

Both JSON::MaybeXS and Mojo::JSON will attempt to call the TO_JSON method of a blessed reference to produce a JSON-friendly structure. If that method does not exist, JSON::MaybeXS will encode the object to null, while Mojo::JSON will stringify the object.

 print encode_json([DateTime->now]);
 # Mojo::JSON: ["2014-11-30T04:31:13"]
 # JSON::MaybeXS: [null]

Unblessed References

JSON::MaybeXS does not allow unblessed references other than to hashes, arrays, or the scalar values 0 and 1, and will encode them to null. Mojo::JSON will treat all scalar references the same as references to 0 or 1 and will encode them to true or false depending on their boolean value. Other references (code, filehandle, etc) will be stringified.

 print encode_json([\'asdf', sub { 1 }]);
 # Mojo::JSON: [true,"CODE(0x11d1650)"]
 # JSON::MaybeXS: [null,null]

Escapes

Mojo::JSON currently escapes the slash character / for security reasons, as well as the unicode characters u2028 and u2029, while JSON::MaybeXS does not. This does not affect decoding of the resulting JSON.

 print encode_json(["/\x{2028}/\x{2029}"]);
 # Mojo::JSON: ["\/\u2028\/\u2029"]
 # JSON::MaybeXS: ["/ / "]
 # Both decode to arrayref containing: "/\x{2028}/\x{2029}"

inf and nan

Mojo::JSON encodes inf and nan to strings, whereas JSON::MaybeXS will encode them differently depending which module is loaded. If it loads Cpanel::JSON::XS (the default if available) version 3.0112 or greater, it will also stringify inf and nan. However, JSON::XS or JSON::PP will encode them as numbers (barewords) producing invalid JSON.

 print encode_json([9**9**9, -sin 9**9**9]);
 # Mojo::JSON or Cpanel::JSON::XS >= 3.0112: ["inf","nan"] (on Linux)
 # JSON::XS or JSON::PP: [inf,nan]

Upgraded Numbers

JSON::MaybeXS, if using JSON::XS or JSON::PP, will attempt to guess if a value to be encoded is numeric or string based on its last usage. Therefore, using a variable containing 13 in a string will cause it to be encoded as "13" even if the variable itself was not changed. Mojo::JSON or Cpanel::JSON::XS version 3.0109 or greater will encode 13 as 13 regardless of whether it has been used as a string.

 my ($num1, $num2) = (13, 14);
 my $str = "$num1";
 print encode_json([$num1, $num2, $str]);
 # Mojo::JSON or Cpanel::JSON::XS >= 3.0109: [13,14,"13"]
 # JSON::XS or JSON::PP: ["13",14,"13"]

BUGS

This is a monkey-patch of one of a few possible modules into another, and they have incompatibilities, so there will probably be bugs. Report any issues on the public bugtracker.

AUTHOR

Dan Book, dbook@cpan.org

CREDITS

Sebastian Riedel, author of Mojolicious, for basic implementation.

COPYRIGHT AND LICENSE

Copyright 2014, Dan Book.

This library is free software; you may redistribute it and/or modify it under the terms of the Artistic License version 2.0.

SEE ALSO

Mojo::JSON, JSON::MaybeXS, Cpanel::JSON::XS, JSON::XS, JSON::PP

cpanm Mojo::JSON::MaybeXS

perl -MCPAN -e shell
install Mojo::JSON::MaybeXS