Karen Etheridge > JSON-MaybeXS > JSON::MaybeXS



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Module Version: 1.002006   Source  


JSON::MaybeXS - Use Cpanel::JSON::XS with a fallback to JSON::XS and JSON::PP


  use JSON::MaybeXS;

  my $data_structure = decode_json($json_input);

  my $json_output = encode_json($data_structure);

  my $json = JSON->new;

  my $json_with_args = JSON::MaybeXS->new(utf8 => 1); # or { utf8 => 1 }


This module first checks to see if either Cpanel::JSON::XS or JSON::XS is already loaded, in which case it uses that module. Otherwise it tries to load Cpanel::JSON::XS, then JSON::XS, then JSON::PP in order, and either uses the first module it finds or throws an error.

It then exports the encode_json and decode_json functions from the loaded module, along with a JSON constant that returns the class name for calling new on.

If you're writing fresh code rather than replacing JSON.pm usage, you might want to pass options as constructor args rather than calling mutators, so we provide our own new method that supports that.


encode_json, decode_json and JSON are exported by default; is_bool is exported on request.

To import only some symbols, specify them on the use line:

  use JSON::MaybeXS qw(encode_json decode_json is_bool); # functions only

  use JSON::MaybeXS qw(JSON); # JSON constant only

To import all available symbols, use :all:

  use JSON::MaybeXS ':all';


This is the encode_json function provided by the selected implementation module, and takes a perl data structure which is serialised to JSON text.

  my $json_text = encode_json($data_structure);


This is the decode_json function provided by the selected implementation module, and takes a string of JSON text to deserialise to a perl data structure.

  my $data_structure = decode_json($json_text);


The JSON constant returns the selected implementation module's name for use as a class name - so:

  my $json_obj = JSON->new; # returns a Cpanel::JSON::XS or JSON::PP object

and that object can then be used normally:

  my $data_structure = $json_obj->decode($json_text); # etc.


  $is_boolean = is_bool($scalar)

Returns true if the passed scalar represents either true or false, two constants that act like 1 and 0, respectively and are used to represent JSON true and false values in Perl.

Since this is a bare sub in the various backend classes, it cannot be called as a class method like the other interfaces; it must be called as a function, with no invocant. It supports the representation used in all JSON backends.



With JSON::PP, JSON::XS and Cpanel::JSON::XS you are required to call mutators to set options, such as:

  my $json = $class->new->utf8(1)->pretty(1);

Since this is a trifle irritating and noticeably un-perlish, we also offer:

  my $json = JSON::MaybeXS->new(utf8 => 1, pretty => 1);

which works equivalently to the above (and in the usual tradition will accept a hashref instead of a hash, should you so desire).


To include JSON-aware booleans (true, false) in your data, just do:

    use JSON::MaybeXS;
    my $true = JSON->true;
    my $false = JSON->false;


mst - Matt S. Trout (cpan:MSTROUT) <mst@shadowcat.co.uk>



Copyright (c) 2013 the JSON::MaybeXS "AUTHOR" and "CONTRIBUTORS" as listed above.


This library is free software and may be distributed under the same terms as perl itself.

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