Add Helper::isValid()

refs #15

Author: Art4

src/Utils/Helper.php

@@ -2,6 +2,7 @@
 
 namespace Art4\JsonApiClient\Utils;
 
+use Art4\JsonApiClient\Exception\Exception;
 use Art4\JsonApiClient\Exception\ValidationException;
 
 /**
@@ -32,6 +33,26 @@ public static function parse($json_string)
 		);
 	}
 
+	/**
+	 * Checks if a string is a valid JSON API
+	 *
+	 * @param string $json_string
+	 * @return bool true, if $json_string contains valid JSON API, else false
+	 */
+	public static function isValid($json_string)
+	{
+		try
+		{
+			$document = static::parse($json_string);
+		}
+		catch ( Exception $e )
+		{
+			return false;
+		}
+
+		return true;
+	}
+
 	/**
 	 * Decodes a json string
 	 *

tests/unit/Utils/HelperTest.php

@@ -39,4 +39,34 @@ public function testParseWithInvalidJsonThrowsException()
 
 		$output = Helper::parse($invalid_json);
 	}
+
+	/**
+	 * @test isValid() with valid JSON API returns true
+	 */
+	public function testIsValidWithValidJsonapi()
+	{
+		$jsonapi = '{"meta":{}}';
+
+		$this->assertTrue(Helper::isValid($jsonapi));
+	}
+
+	/**
+	 * @test isValid() with invalid jsonapi
+	 */
+	public function testIsValidWithInvalidJsonapi()
+	{
+		$invalid_jsonapi = '["This is valid JSON", "but invalid JSON API"]';
+
+		$this->assertFalse(Helper::isValid($invalid_jsonapi));
+	}
+
+	/**
+	 * @test isValid() with invalid json
+	 */
+	public function testIsValidWithInvalidJson()
+	{
+		$invalid_json = 'invalid_json_string';
+
+		$this->assertFalse(Helper::isValid($invalid_json));
+	}
 }