Provided by: libjson-path-perl_0.431-1_all 
NAME
JSON::Path - search nested hashref/arrayref structures using JSONPath
VERSION
version 0.431
SYNOPSIS
my $data = {
"store" => {
"book" => [
{ "category" => "reference",
"author" => "Nigel Rees",
"title" => "Sayings of the Century",
"price" => 8.95,
},
{ "category" => "fiction",
"author" => "Evelyn Waugh",
"title" => "Sword of Honour",
"price" => 12.99,
},
{ "category" => "fiction",
"author" => "Herman Melville",
"title" => "Moby Dick",
"isbn" => "0-553-21311-3",
"price" => 8.99,
},
{ "category" => "fiction",
"author" => "J. R. R. Tolkien",
"title" => "The Lord of the Rings",
"isbn" => "0-395-19395-8",
"price" => 22.99,
},
],
"bicycle" => [
{ "color" => "red",
"price" => 19.95,
},
],
},
};
use JSON::Path 'jpath_map';
# All books in the store
my $jpath = JSON::Path->new('$.store.book[*]');
my @books = $jpath->values($data);
# The author of the last (by order) book
my $jpath = JSON::Path->new('$..book[-1:].author');
my $tolkien = $jpath->value($data);
# Convert all authors to uppercase
jpath_map { uc $_ } $data, '$.store.book[*].author';
DESCRIPTION
This module implements JSONPath, an XPath-like language for searching JSON-like
structures.
JSONPath is described at <http://goessner.net/articles/JsonPath/>.
Constructor
"JSON::Path->new($string)"
Given a JSONPath expression $string, returns a JSON::Path object.
Methods
"values($object)"
Evaluates the JSONPath expression against an object. The object $object can be either
a nested Perl hashref/arrayref structure, or a JSON string capable of being decoded by
JSON::MaybeXS::decode_json.
Returns a list of structures from within $object which match against the JSONPath
expression. In scalar context, returns the number of matches.
"value($object)"
Like "values", but returns just the first value. This method is an lvalue sub, which
means you can assign to it:
my $person = { name => "Robert" };
my $path = JSON::Path->new('$.name');
$path->value($person) = "Bob";
TAKE NOTE! This will create keys in $object. E.G.:
my $obj = { foo => 'bar' };
my $path = JSON::Path->new('$.baz');
$path->value($obj) = 'bak'; # $obj->{baz} is created and set to 'bak';
"paths($object)"
As per "values" but instead of returning structures which match the expression,
returns canonical JSONPaths that point towards those structures.
"get($object)"
In list context, identical to "values", but in scalar context returns the first
result.
"set($object, $value, $limit)"
Alters $object, setting the paths to $value. If set, then $limit limits the number of
changes made.
TAKE NOTE! This will create keys in $object. E.G.:
my $obj = { foo => 'bar' };
my $path = JSON::Path->new('$.baz');
$path->set($obj, 'bak'); # $obj->{baz} is created and set to 'bak'
Returns the number of changes made.
"map($object, $coderef)"
Conceptually similar to Perl's "map" keyword. Executes the coderef (in scalar
context!) for each match of the path within the object, and sets a new value from the
coderef's return value. Within the coderef, $_ may be used to access the old value,
and $. may be used to access the curent canonical JSONPath.
"to_string"
Returns the original JSONPath expression as a string.
This method is usually not needed, as the JSON::Path should automatically stringify
itself as appropriate. i.e. the following works:
my $jpath = JSON::Path->new('$.store.book[*].author');
print "I'm looking for: " . $jpath . "\n";
Functions
The following functions are available for export, but are not exported by default:
"jpath($object, $path_string)"
Shortcut for "JSON::Path->new($path_string)->values($object)".
"jpath1($object, $path_string)"
Shortcut for "JSON::Path->new($path_string)->value($object)". Like "value", it can be
used as an lvalue.
"jpath_map { CODE } $object, $path_string"
Shortcut for "JSON::Path->new($path_string)->map($object, $code)".
NAME
JSON::Path - search nested hashref/arrayref structures using JSONPath
PERL SPECIFICS
JSONPath is intended as a cross-programming-language method of searching nested object
structures. There are however, some things you need to think about when using JSONPath in
Perl...
JSONPath Embedded Perl Expressions
JSONPath expressions may contain subexpressions that are evaluated using the native host
language. e.g.
$..book[?($_->{author} =~ /tolkien/i)]
The stuff between "?(" and ")" is a Perl expression that must return a boolean, used to
filter results. As arbitrary Perl may be used, this is clearly quite dangerous unless used
in a controlled environment. Thus, it's disabled by default. To enable, set:
$JSON::Path::Safe = 0;
There are some differences between the JSONPath spec and this implementation.
• JSONPath uses a variable '$' to refer to the root node. This is not a legal variable
name in Perl, so '$root' is used instead.
• JSONPath uses a variable '@' to refer to the current node. This is not a legal
variable name in Perl, so '$_' is used instead.
Blessed Objects
Blessed objects are generally treated as atomic values; JSON::Path will not follow paths
inside them. The exception to this rule are blessed objects where:
Scalar::Util::blessed($object)
&& $object->can('typeof')
&& $object->typeof =~ /^(ARRAY|HASH)$/
which are treated as an unblessed arrayref or hashref appropriately.
BUGS
Please report any bugs to <http://rt.cpan.org/>.
SEE ALSO
Specification: <http://goessner.net/articles/JsonPath/>.
Implementations in PHP, Javascript and C#: <http://code.google.com/p/jsonpath/>.
Related modules: JSON, JSON::JOM, JSON::T, JSON::GRDDL, JSON::Hyper, JSON::Schema.
Similar functionality: Data::Path, Data::DPath, Data::SPath, Hash::Path,
Path::Resolver::Resolver::Hash, Data::Nested, Data::Hierarchy... yes, the idea's not
especially new. What's different is that JSON::Path uses a vaguely standardised syntax
with implementations in at least three other programming languages.
AUTHOR
Toby Inkster <tobyink@cpan.org>.
MAINTAINER
Kit Peters <popefelix@cpan.org>
CONTRIBUTORS
Szymon Nieznański <s.nez@member.fsf.org>
Kit Peters <popefelix@cpan.org>
Heiko Jansen <hjansen@cpan.org>.
Mitsuhiro Nakamura <m.nacamura@gmail.com>
COPYRIGHT AND LICENCE
Copyright 2007 Stefan Goessner.
Copyright 2010-2013 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.
AUTHOR
Kit Peters <popefelix@gmail.com>
COPYRIGHT AND LICENSE
This software is copyright (c) 2021 by Kit Peters.
This is free software; you can redistribute it and/or modify it under the same terms as
the Perl 5 programming language system itself.