Added ISBN validation before hitting providers

Author: sprain

composer.json

@@ -10,7 +10,8 @@
     ],
     "require": {
         "kriswallsmith/buzz": "~0.12",
-        "symfony/intl": "~2.5.4"
+        "symfony/intl": "~2.5.4",
+        "symfony/validator": "~2.5.4"
     },
     "autoload": {
         "psr-4": { "Sprain\\BookFinder\\": "lib/BookFinder" }

lib/BookFinder/BookFinder.php

@@ -2,6 +2,8 @@
 
 namespace Sprain\BookFinder;
 use Sprain\BookFinder\Response\BookFinderResponse;
+use Symfony\Component\Validator\Constraints\Isbn;
+use Symfony\Component\Validator\Validation;
 
 /**
  * BookFinder
@@ -31,6 +33,16 @@ public function searchByIsbn($isbn)
         $isbn = trim($isbn);
         $isbn = str_replace('-', '', $isbn);
 
+        // Validate isbn
+        $validator = Validation::createValidator();
+        $violations = $validator->validateValue($isbn, new Isbn());
+
+        if (count($violations) > 0) {
+            
+            return false;
+        }
+
+        // Use providers to search for book
         foreach($this->providers as $provider){
             $result = $provider['provider']->searchByIsbn($isbn)->getResult();