docs: schema validation example

Author: Greg Bowler

example/03-schema.php

@@ -0,0 +1,68 @@
+<?php
+// The JSON we will validate. Notice that one of the array keys is not a string,
+// and the "colour" property is misspelled.
+use Gt\Json\JsonObjectBuilder;
+use Gt\Json\Schema\ValidationError;
+use Gt\Json\Schema\Validator;
+
+require __DIR__ . "/../vendor/autoload.php";
+
+$jsonString = <<<JSON
+{
+	"name": "Cody",
+	"colr": "orange",
+	"food": [
+		"Biscuits",
+		"Mushrooms",
+		12345
+	]
+}
+JSON;
+
+$schemaString = <<<JSON
+{
+	"\$schema": "https://json-schema.org/draft/2020-12/schema",
+	"title": "Simple object schema",
+	"type": "object",
+	"properties": {
+		"name": {
+			"type": "string",
+			"minLength": 1
+		},
+		"colour": {
+			"type": "string"
+		},
+		"food": {
+			"type": "array",
+			"items": {
+				"type": "string"
+			}
+		}
+	},
+	"required": [
+		"name",
+		"colour",
+		"food"
+	],
+	"additionalProperties": false
+}
+JSON;
+
+$builder = new JsonObjectBuilder();
+
+$schema = $builder->fromJsonString($schemaString);
+$json = $builder->fromJsonString($jsonString);
+
+$validator = new Validator($schema);
+$result = $validator->validate($json);
+
+if($result instanceof ValidationError) {
+	echo "Error validating JSON!", PHP_EOL;
+
+	foreach($result->getErrorList() as $propertyName => $errorString) {
+		echo "$propertyName: $errorString", PHP_EOL;
+	}
+}
+else {
+	echo "Everything is OK!", PHP_EOL;
+}

src/JsonObjectBuilder.php

@@ -98,7 +98,7 @@ public function fromFile(string $filePath):JsonObject {
 			throw new FileNotFoundException($filePath);
 		}
 
-		return self::fromJsonString(file_get_contents($filePath));
+		return self::fromJsonString(file_get_contents($filePath) ?: "");
 	}
 
 }

src/Schema/ValidationError.php

@@ -10,7 +10,7 @@
 class ValidationError extends ValidationResult implements JsonSerializable {
 	/** @param array<string> $errorList */
 	public function __construct(
-		private JsonKvpObject $schema,
+		private JsonObject $schema,
 		private array $errorList,
 	) {}
 

src/Schema/Validator.php

@@ -8,7 +8,7 @@
 
 class Validator {
 	public function __construct(
-		private ?JsonKvpObject $schema = null,
+		private ?JsonObject $schema = null,
 	) {}
 
 	public function validate(JsonObject $json):ValidationResult {