Validating JSON with JSON Schema

Validating your JSON

About me → Anne-Julia Scheuermann → Creating Web-Applications since 2004
→ Developing information literacy solutions for

Short Story API DB JSON

Custom validation

Custom validation protected function isValidUnformatted(array $data) { if (empty($data['data'])) {
return false; // no data sent } $data = $data['data']; $source = $data['source']; $style = empty($data['style']) ? null : $data['style']; $structure = $this->getStructure($source, $style); $allowedTopLevelFields = $this->getOtherValidFields(); $ignoredDataFields = $this->getIgnoredFields(); // source if (!empty($structure['source_data'])) { if (empty($data[$source])) { $this->errors[] = 'needed source data missing'; return false; } $notAllowed = array_diff_key($data[$source], array_flip($structure['source_data'])); // +300 lines of code more

Many lines of complex code

PHPMD warnings /!\ /** * @param array $data * *
@Todo Fix suppressed warnings * @SuppressWarnings( * PHPMD.CyclomaticComplexity, * PHPMD.NPathComplexity * ) * @return bool */ protected function isValidUnformatted(array $data) { //...

Validation only on server side API DB JSON

Other technologies have solved this

DTD for SGML <!DOCTYPE HTML PUBLIC ”-//W3C//DTD HTML 4.01//EN” ”http://www.w3.org/TR/html4/strict.dtd”>
 <!ENTITY % coreattrs ”id ID #IMPLIED -- document-wide unique id -- class CDATA #IMPLIED -- space-separated list of classes -- style %StyleSheet; #IMPLIED -- associated style info -- title %Text; #IMPLIED -- advisory title --” >

XSD for XML (XHTML) <?xml version=”1.0”?> <xs:schema xmlns:xs=”http://www.w3.org/2001/XMLSchema”> <xs:element name=”note”>
<xs:complexType> <xs:sequence> <xs:element name=”to” type=”xs:string”/> <xs:element name=”from” type=”xs:string”/> <xs:element name=”body” type=”xs:string”/> </xs:sequence> </xs:complexType> </xs:element> </xs:schema>

Short Story API DB JSON

JSON Schema → http://json-schema.org/

Hello World! 42 ”42” {} true

JSON Schema specification Validation Core

type {“type”: “string”} {“type”: “integer”} {“type”: “array”} {“type”: “object”} {“type”:
“boolean”} {“type”: “null”} {“type”: “number”}

string

string ”Hello World!” ”42” {”type”: ”string”} 42

”php” string length { ”type”: ”string”, ”minLength”: 2, ”maxLength”: 3
} ”i <? php” ”p”

string pattern { ”type”: ”string”, ”pattern”: ”^and.+$” } ”iphone” ”android”

numeric

integer -1 42 0.5 “42” { ”type”: ”integer” }

number -1 42 0.5 2.99792458e8 { ”type”: ”number” }

number range 10 11 40 { ”type”: ”number”, “minimum”: 10,
“maximum”: 40, “exclusiveMinimum”: true, “exclusiveMaximum”: false }

array [1, 2, 3, 4, 5] [1, “2”, {“3”:”4 and
5”}, [42]] {”type”: ”array”} {“this”: “is an object”}

array items [] [1, 2, 3, 4, 5] [1, 2,
3, 4, “5”] { ”type”: ”array”, “items”: {“type”: “number”} }

array length [] [1] [1, 2] { ”type”: ”array”, “minItems”:
1, “maxItems”: 2 } [1, 2, 3]

object

object { ”key”: ”value”, ”anotherKey”: ”anotherValue” } {”type”: ”object”} ”42”
[“hello”, “world”]

{”author”: ”A. A. Milne”, ”year”: 1882} properties { ”type”: ”object”,
”properties”: { ”author”: {”type”: ”string”}, ”year”: {”type”: ”number”} } } {”year”: ”1882”} {”author”: ”A. A. Milne”} {}

{”author”: ”A. A Milne”, ”title”: 1882} required properties { ”type”:
”object”, ”properties”: { ”author”: {”type”: ”string”}, ”title”: {”type”: ”string”}}, ”required”: [”title”] } {} {”author”: ”A. A Milne”, ”title”: ”Winni the Pooh”, ”year”: 1926} {”author”: “A. A Milne”}

additional properties { ”type”: ”object”, ”properties”: { ”author”: {”type”: ”string”},
”title”: {”type”: ”string”} }, ”additionalProperties”: false } {”title”: []} {} {”author”: ”A. A. Milne”, ”title”: ”Winni the Pooh”, ”year”: 1926} {”author”: ”A. A. Milne”, ”title”: ”Winni the Pooh”}

{”a”: ”aa”, “b”: “bb”} number of properties { ”type”: ”object”,
”minProperties”: 1, ”maxProperties”: 2 } {} {”a”: ”aa”} {”a”: ”aa”, “b”: “bb”, “c”: “cc”}

dependencies

{”name”: ”Alan”, “birthday”: “1882-01-18”} property dependencies { ”type”: ”object”, ”properties”:
{“name”: {“type”: “string”}, “birthday”: {“type”: “string”}}, ”dependencies”: { “birthday”: [“name”]} } {”name”: ”Alan”} {“birthday”: “1882-01-18”}

{”name”: ”Alan”, “birthday”: “1882-01-18”} schema dependencies { ”type”: ”object”, ”properties”:
{ “birthday”: {“type”: “string”}}, ”dependencies”: { “birthday”: { “properties”: {“name”: {“type”: “string”}}}} } {”name”: ”Alan”} {“birthday”: “1882-01-18”}

{”PHPUnit”: ”testing”, “PHPCS”: “styling”} pattern properties { ”type”: ”object”, ”patternProperties”:
{ “^PHP”: {“type”: “string”}}, “additionalProperties”: {“type”: “integer”} } {”BeHat”: ”accepting”} {“PHPLOC”: 9001} {“LOC”: 9001}

boolean

boolean true false {”type”: ”boolean”} “true” 0

null null false {”type”: ”null”} “” 0

More features

“one” “eleven” 1 -11 Combining with oneOf, anyOf, allOf {
”anyOf”: [ {“type”: “string”, “maxLength”: 5}, {“type”: “number”, “minimum”: 0} ] }

not “42” {“key”: 42} 42 { ”not”: {“type”: “number”} }

available formats: email, date-time, hostname, ipv4, ipv6, uri ”[email protected]” ”ab@mail.”
built-in formats { ”format”: ”email” }

JSON Schema specification Validation Core

title, description & default { ”title”: ”Expressive title”, ”description”: “Take
time to explain”, ”default”: “Validators ignore this keyword” }

$schema { “$schema”: “http://json-schema.org/draft-04/schema#”, ”title”: ”Expressive title”, ”description”: “Take time
to explain”, ”default”: “Validators ignore this keyword” }

definitions { “$schema”: “http://json-schema.org/draft-04/schema#”, “definitions”: { "address": { "type": "object",
"properties": { "street_address": { "type": "string" }, "city": { "type": "string" }, "state": { "type": "string" } }, "required": ["street_address", "city", "state"] } } }

$ref & definitions { “$schema”: “http://json-schema.org/draft-04/schema#”, “definitions”: { "address": {
"type": "object", "properties": { "street_address": { "type": "string" }, "city": { "type": "string" }, "state": { "type": "string" } }, "required": ["street_address", "city", "state"] } } "type": "object", "properties": { "billing_address": { "$ref": "#/definitions/address" }, "shipping_address": { "$ref": "#/definitions/address" } } }

$ref & definitions { “$schema”: “http://json-schema.org/draft-04/schema#”, “description”: “This schema defines
an address”, "type": "object", "properties": { "city": { "type": "string" }, "state": { "type": "string" } }, "required": ["street_address", "city", "state"] } { “$schema”: “http://json-schema.org/draft-04/schema#”, “description”: “This schema describes an order”, "type": "object", "properties": { "billing_address": { "$ref": "address.json#" }, "shipping_address": { "$ref": "address.json#" } } } address.json order.json

Breathe!

Validation Libraries

Validation Libraries geraintluff/jsv4-php 11 commits, 1 contributor hasbridge/php-json-schema 28 commits,
2 contributors, not yet feature complete justinrainbow/json-schema 202 commits, 21 contributors

Integration of schema validation

Preparing validation with json-schema // Get the schema as object
$retriever = new JsonSchema\Uri\UriRetriever; $schema = $retriever->retrieve('file://' . realpath('schema.json')); // Resolve references $refResolver = new JsonSchema\RefResolver($retriever); $refResolver->resolve($schema, 'file://' . __DIR__);

Validation with json-schema /** * Validate json against schema *
* @param string $data * @param string $schema * * @return bool */ public function isValid($data, $schema) { $data = json_decode($data); $this->validator->check($data, $schema); $this->errors = $this->validator->getErrors(); return $this->validator->isValid(); }

The benefits of using JSON Schema

Less code /** * Validate json against schema * *
@param string $data * @param string $schema * * @return bool */ public function isValid($data, $schema) { $data = json_decode($data); $this->validator->check($data, $schema); $this->errors = $this->validator->getErrors(); return $this->validator->isValid(); }

No custom validation

Complexity Complexity of validation and document structure is independent

Validation on client and server side API DB JSON

Implementation in many languages PHP, JavaScript, Java, Python, Ruby, Perl,
.NET, C, Haskell, Erlang, Go

Better user experience Clear, human- and machine-readable documentation of our
data structure

Thank You! • http://json-schema.org/ • http://tools.ietf.org/html/draft-zyp-json-schema-04 • https://en.wikipedia.org/wiki/JSON • http://spacetelescope.github.io/understanding-json-schema/
• https://packagist.org/packages/justinrainbow/json-schema • http://getcomposer.org

Questions?

Validating JSON with JSON Schema

Validating JSON with JSON Schema

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