NAME

JSON::Hyper - extract links from JSON via a schema

SYNOPSIS

my $hyper = JSON::Hyper->new($hyperschema);
my $json  = from_json( ... );
my @links = $hyper->find_links($json->[1]->{some}->{object});
foreach my $link (@links)
{
  printf("<%s> (%s)", $link->{href}, $link->{rel});
}

DESCRIPTION

The JSON Hyper Schema proposal defines hypertext navigation through data structures represented by JSON.

Constructor

new($hyperschema)

Given a JSON (or equivalent Perl nested hashref/arrayref structure) Hyper Schema, returns a Perl object capable of interpreting that schema.

If the schema is omitted, defaults to the JSON Referencing hyper schema (described at http://json-schema.org/json-ref)

Methods

schema

Returns the original schema as a hashref/arrayref structure.

ua

Get/set the LWP::UserAgent instance used to retrieve things.

find_links($object, $base)

Given a JSON object (or equivalent Perl nested hashref/arrayref structure) and optionally a base URL for interpreting relative URI references, returns a list of links found on object node. Does not operate recursively.

Each link is a JSON::Hyper::Link object.

get($uri)

Performs an HTTP request for the given URI and returns a list of Perl nested hashref/arrayref structures corresponding to the JSON response. The URI may contain a fragment identifier, which will be interpreted according to the schema's fragment resolution method. Fragment resolution methods supported include:

• slash-delimited (default)

• dot-delimited

• jsonpath

For example, assuming the hyper schema specifies slash-delimited fragments, the following:

my $hyper    = JSON::Hyper->new($hyperschema);
my ($result) = $hyper->get('http://example.com/data.json#foo/bar/0');

Is roughly equivalent to:

use JSON;
use LWP::UserAgent;
my $ua       = LWP::UserAgent->new;
my $response = $ua->get('http://example.com/data.json');
my $object   = from_json($response->decoded_content);
my $result   = $object->{foo}{bar}[0];

Note, if called multiple times on the same URL will return not just equivalent objects, but the same object.

So, why does this method return a list of results instead of just a single result? In most cases, there will be either 0 or 1 items on the list; however, JSONPath allows a path to match multiple nodes, so there will occasionally be more than one result. (In scalar context, this method just returns the first result anyway.)

resolve_fragment($object, $fragment)

Used by get to resolve the fragment part of a URL against an object.

process_includes($object, $base, $recurse)

Given an JSON object (or equivalent Perl nested hashref/arrayref structure) and optional base URL, crawls the object finding rel="full" links, dereferences them using get and replaces the appropriate nodes with the retrieved content. $recurse is a boolean.

This has the effect of rel="full" behaving like inclusion does in various programming languages.

This modifies the given object rather than creating a new object.

Utilities

JSON::Hyper::json_ref()

Returns the JSON referencing hyperschema as a hashref.

BUGS

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

SEE ALSO

JSON::Hyper::Link.

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

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

AUTHOR

Toby Inkster <tobyink@cpan.org>.

COPYRIGHT AND LICENCE

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.