NAME
    JSON::Schema - validate JSON against a schema

SYNOPSIS
     my $validator = JSON::Schema->new($schema, %options);
     my $json      = from_json( ... );
     my $result    = $validator->validate($json);
 
     if ($result)
     {
       print "Valid!\n";
     }
     else
     {
       print "Errors\n";
       print " - $_\n" foreach $result->errors;
     }

STATUS
    This module offers good support for JSON Schema as described by draft
    specifications circa 2012.

    However, since then the JSON Schema draft specifications have changed
    significantly. It is planned for this module to be updated to support the
    changes, however this work will not be undertaken until the JSON Schema
    specifications become more stable. (Being published as an IETF RFC will be
    seen as sufficient stability.)

DESCRIPTION
  Constructors
    `JSON::Schema->new($schema, %options)`
        Given a JSON (or equivalent Perl nested hashref/arrayref structure)
        Schema, returns a Perl object capable of checking objects against that
        schema.

        Note that some schemas contain '$ref' properties which act as
        inclusions; this module does not expand those, but the JSON::Hyper
        module can.

        The only option currently supported is 'format' which takes a hashref
        of formats (section 5.23 of the current JSON Schema draft) such that
        the keys are the names of the formats, and the values are regular
        expressions or callback functions. %JSON::Schema::FORMATS provides a
        library of useful format checkers, but by default no format checkers
        are used.

         my $s = JSON::Schema->new($schema,
                                   format => \%JSON::Schema::FORMATS);

    `JSON::Schema->detect($url)`
        Given the URL for a JSON instance (or an HTTP::Response object)
        returns a list of schemas (as JSON::Schema objects) that the JSON
        instance claims to conform to, detected from the HTTP response
        headers.

  Methods
    `validate($object)`
        Validates the object against the schema and returns a
        JSON::Schema::Result.

    `schema`
        Returns the original schema as a hashref/arrayref structure.

    `format`
        Returns the hashref of format checkers.

    `ua`
        Returns the LWP::UserAgent that this schema object has used or would
        use to retrieve content from the web.

  Perl Specifics
    Perl uses weak typing. This module largely gives JSON instances the
    benefit of the doubt. For example, if something looks like a number (e.g.
    a string which only includes the digits 0 to 9) then it will validate
    against schemas that require a number.

    The module extends JSON Schema's native set of types ('string', 'number',
    'integer', 'boolean', 'array', 'object', 'null', 'any') with any Perl
    package name. i.e. the following is valid:

      my $validator = JSON::Schema->new({
        properties => { 
          'time' => { type => ['DateTime','string'] },
        },
      });
      my $object = {
        'time' => DateTime->now;
      };
      my $result = $schema->validate($object);

    This extension makes JSON::Schema useful not just for validating JSON
    structures, but acyclic Perl structures generally.

    Acyclic. Yes, acyclic. You don't want an infinite loop.

BUGS
    Please report any bugs to <http://rt.cpan.org/>.

SEE ALSO
    JSON::Schema::Result, JSON::Schema::Error, JSON::Schema::Helper,
    JSON::Schema::Null, JSON::Schema::Examples.

    Related modules: JSON::T, JSON::Path, JSON::GRDDL, JSON::Hyper.

    <http://tools.ietf.org/html/draft-zyp-json-schema>.

AUTHOR
    Toby Inkster <tobyink@cpan.org>.

    This is largely a port of Kris Zyp's Javascript JSON Schema validator
    <http://code.google.com/p/jsonschema/>.

COPYRIGHT AND LICENCE
    Copyright 2007-2009 Kris Zyp.

    Copyright 2010-2012 Toby Inkster.

    This module is tri-licensed. It is available under the X11 (a.k.a. MIT)
    licence; you can also redistribute it and/or modify it under the same
    terms as Perl itself.

  a.k.a. "The MIT Licence"
    Permission is hereby granted, free of charge, to any person obtaining a
    copy of this software and associated documentation files (the "Software"),
    to deal in the Software without restriction, including without limitation
    the rights to use, copy, modify, merge, publish, distribute, sublicense,
    and/or sell copies of the Software, and to permit persons to whom the
    Software is furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included in
    all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
    DEALINGS IN THE SOFTWARE.

