NAME
JSON::Validator - Validate data against a JSON schema
VERSION
1.04
SYNOPSIS
use JSON::Validator;
my $validator = JSON::Validator->new;
# Define a schema - http://json-schema.org/examples.html
# You can also load schema from disk or web
$validator->schema(
{
type => "object",
required => ["firstName", "lastName"],
properties => {
firstName => {type => "string"},
lastName => {type => "string"},
age => {type => "integer", minimum => 0, description => "Age in years"}
}
}
);
# Validate your data
@errors = $validator->validate({firstName => "Jan Henning", lastName => "Thorsen", age => -42});
# Do something if any errors was found
die "@errors" if @errors;
DESCRIPTION
JSON::Validator is a class for validating data against JSON schemas. You
might want to use this instead of JSON::Schema if you need to validate
data against draft 4
<https://github.com/json-schema/json-schema/tree/master/draft-04> of the
specification.
This module can be used standalone, but if you want to define a
specification for your webserver's API, then have a look at
Mojolicious::Plugin::OpenAPI, which will replace
Mojolicious::Plugin::Swagger2.
Supported schema formats
JSON::Validator can load JSON schemas in multiple formats: Plain perl
data structured (as shown in "SYNOPSIS") or files on disk/web in the
JSON/YAML format. The JSON parsing is done using Mojo::JSON, while the
YAML parsing is done with an optional modules which need to be installed
manually. JSON::Validator will look for the YAML modules in this order:
YAML::XS, YAML::Syck. The order is set by which module that performs the
best, so it might change in the future.
Resources
Here are some resources that are related to JSON schemas and validation:
* <http://json-schema.org/documentation.html>
* <http://spacetelescope.github.io/understanding-json-schema/index.htm
l>
* <https://github.com/json-schema/json-schema/>
* Swagger2
Bundled specifications
This module comes with some JSON specifications bundled, so your
application don't have to fetch those from the web. These specifications
should be up to date, but please submit an issue if they are not.
Files referenced to an URL will automatically be cached if the first
element in "cache_paths" is a writable directory. Note that the cache
headers for the remote assets are not honored, so you will manually need
to remove any cached file, should you need to refresh them.
To download and cache an online asset, do this:
JSON_VALIDATOR_CACHE_PATH=/some/writable/directory perl myapp.pl
Here is the list of the bundled specifications:
* JSON schema, draft 4
Web page: <http://json-schema.org>
$ref: <http://json-schema.org/draft-04/schema#>
* JSON schema for JSONPatch files
Web page: <http://jsonpatch.com>
$ref: <http://json.schemastore.org/json-patch#>
* Swagger / OpenAPI specification, version 2
Web page: <https://openapis.org>
$ref: <http://swagger.io/v2/schema.json#>
* Custom error document
There is a custom schema used by Mojolicious::Plugin::OpenAPI as a
default error document. This document might be extended later, but it
will always be backward compatible.
Specification:
<https://github.com/jhthorsen/json-validator/blob/master/lib/JSON/Vali
dator/cache/630949337805585c8e52deea27d11419>
$ref: <http://git.io/vcKD4#>.
* Swagger Petstore
This is used for unit tests, and should probably not be relied on by
external users.
ERROR OBJECT
Overview
The method "validate" and the function "validate_json" returns error
objects when the input data violates the "schema". Each of the objects
looks like this:
bless {
message => "Some description",
path => "/json/path/to/node",
}, "JSON::Validator::Error"
See also JSON::Validator::Error.
Operators
The error object overloads the following operators:
* bool
Returns a true value.
* string
Returns the "path" and "message" part as a string: "$path:
$message".
Special cases
Have a look at the test suite
<https://github.com/jhthorsen/json-validator/tree/master/t> for
documented examples of the error cases. Especially look at "jv-allof.t",
"jv-anyof.t" and "jv-oneof.t".
The special cases for "allOf", "anyOf" and "oneOf" will contain the
error messages from all the failing rules below. It can be a bit hard to
read, so if the error message is long, then you might want to run a
smaller test with "JSON_VALIDATOR_DEBUG=1".
Example error object:
bless {
message => "(String is too long: 8/5. String is too short: 8/12)",
path => "/json/path/to/node",
}, "JSON::Validator::Error"
Note that these error messages are subject for change. Any suggestions
are most welcome!
FUNCTIONS
validate_json
use JSON::Validator "validate_json";
@errors = validate_json $data, $schema;
This can be useful in web applications:
@errors = validate_json $c->req->json, "data://main/spec.json";
See also "validate" and "ERROR OBJECT" for more details.
ATTRIBUTES
cache_paths
$self = $self->cache_paths(\@paths);
$array_ref = $self->cache_paths;
A list of directories to where cached specifications are stored.
Defaults to "JSON_VALIDATOR_CACHE_PATH" environment variable and the
specs that is bundled with this distribution.
"JSON_VALIDATOR_CACHE_PATH" can be a list of directories, each separated
by ":".
See "Bundled specifications" for more details.
formats
$hash_ref = $self->formats;
$self = $self->formats(\%hash);
Holds a hash-ref, where the keys are supported JSON type "formats", and
the values holds a code block which can validate a given format.
Note! The modules mentioned below are optional.
* date-time
An RFC3339 timestamp in UTC time. This is formatted as
"YYYY-MM-DDThh:mm:ss.fffZ". The milliseconds portion (".fff") is
optional
* email
Validated against the RFC5322 spec.
* hostname
Will be validated using Data::Validate::Domain if installed.
* ipv4
Will be validated using Data::Validate::IP if installed or fall back
to a plain IPv4 IP regex.
* ipv6
Will be validated using Data::Validate::IP if installed.
* regex
EXPERIMENTAL. Will check if the string is a regex, using "qr{...}".
* uri
Validated against the RFC3986 spec.
resolver
$code = $self->resolver;
$self = $self->resolver(sub { my ($self, $namespace, $refs) = @_; });
Set this to a sub without any logic if you want to skip resolving
references, like this:
$self->resolver(sub {});
This attribute is EXPERIMENTAL.
ua
$ua = $self->ua;
$self = $self->ua(Mojo::UserAgent->new);
Holds a Mojo::UserAgent object, used by "schema" to load a JSON schema
from remote location.
Note that the default Mojo::UserAgent will detect proxy settings and
have "max_redirects" in Mojo::UserAgent set to 3. (These settings are
EXPERIMENTAL and might change without a warning)
METHODS
coerce
$self = $self->coerce(booleans => 1, numbers => 1, strings => 1);
$self = $self->coerce({booleans => 1, numbers => 1, strings => 1});
$self = $self->coerce(1) # enable all
$hash = $self->coerce;
Set the given type to coerce. Before enabling coercion this module is
very strict when it comes to validating types. Example: The string "1"
is not the same as the number 1, unless you have coercion enabled.
WARNING! Enabling coercion might hide bugs in your api, which would have
been detected if you were strict. For example JavaScript is very picky
on a number being an actual number. This module tries it best to convert
the data on the fly into the proper value, but this means that you unit
tests might be ok, but the client side libraries (that care about types)
might break.
Loading a YAML document will enable "booleans" automatically. This
feature is experimental, but was added since YAML has no real concept of
booleans, such as Mojo::JSON or other JSON parsers.
The coercion rules are EXPERIMENTAL and will be tighten/loosen if bugs
are reported. See <https://github.com/jhthorsen/json-validator/issues/8>
for more details.
load_and_validate_schema
$self = $self->load_and_validate_schema($schema, \%args);
Will load and validate $schema against the OpenAPI specification.
$schema can be anything "schema" in JSON::Validator accepts. The
expanded specification will be stored in "schema" in JSON::Validator on
success. See "schema" in JSON::Validator for the different version of
$url that can be accepted.
%args can be used to further instruct the validation process:
* schema
Defaults to "http://json-schema.org/draft-04/schema#", but can be any
structured that can be used to validate $schema.
schema
$self = $self->schema($json_or_yaml_string);
$self = $self->schema($url);
$self = $self->schema(\%schema);
$schema = $self->schema;
Used to set a schema from either a data structure or a URL.
$schema will be a Mojo::JSON::Pointer object when loaded, and "undef" by
default.
The $url can take many forms, but needs to point to a text file in the
JSON or YAML format.
* http://... or https://...
A web resource will be fetched using the Mojo::UserAgent, stored in
"ua".
* data://Some::Module/file.name
This version will use "data_section" in Mojo::Loader to load
"file.name" from the module "Some::Module".
* /path/to/file
An URL (without a recognized scheme) will be loaded from disk.
singleton
$self = $class->singleton;
Returns the JSON::Validator object used by "validate_json".
validate
@errors = $self->validate($data);
@errors = $self->validate($data, $schema);
Validates $data against a given JSON "schema". @errors will contain
validation error objects or be an empty list on success.
See "ERROR OBJECT" for details.
$schema is optional, but when specified, it will override schema stored
in "schema". Example:
$self->validate({hero => "superwoman"}, {type => "object"});
COPYRIGHT AND LICENSE
Copyright (C) 2014-2015, Jan Henning Thorsen
This program is free software, you can redistribute it and/or modify it
under the terms of the Artistic License version 2.0.
AUTHOR
Jan Henning Thorsen - "jhthorsen@cpan.org"
Daniel Böhmer - "post@daniel-boehmer.de"
Kevin Goess - "cpan@goess.org"
Martin Renvoize - "martin.renvoize@gmail.com"