Added real ark minting from the postgres ark cache

src/ark/ArkManager.php

@@ -33,7 +33,7 @@ class ArkManager {
      * Sets up the ArkManager
      */
     public function __construct() {
-        $db = new \ark\database\DatabaseConnector();
+        $this->db = new \ark\database\DatabaseConnector();
     }
 
     /**
@@ -71,14 +71,37 @@ class ArkManager {
      * Mint a real, unique, permanent, resolvable ark.  Once an ark is minted using this method, it will never be reassigned. This
      * process is irreversible, so use with caution.  Because of this, only one may be requested at a time.
      *
-     * @return string A new permanent arkID
+     * @return string|boolean A new permanent arkID or false if an ark could not be minted
      */
     public function mintArk() {
+        try {
+            // get the first ark in the list while deleting it (returning *) so that it is atomic
+            $resource = $this->db->query("delete from unassigned_arks 
+                                    where id = (select min(id) from unassigned_arks) 
+                                    returning *;", array());
+            $result = $this->db->fetchRow($resource);
 
+            // If the result exists, is not false, and has an ark, then return the ark
+            if ($result !== false && is_array($result) && isset($result['ark']))
+                return $result['ark'];
+
+        } catch (\Exception $e) {
+            // Something went wrong, so no ark can be returned
+            return false;
+        }
+        
+        return false;
     }
 
-    private function generateRandomString() {
-        $length = 7;
+    /**
+     * Generate a random string
+     *
+     * Generate a random ASCII string of a given length.  The default length is 7 for temporary ARK URL generation.
+     *
+     * @param integer $length optional The length of string to generate
+     * @param string A random ASCII string
+     */
+    private function generateRandomString($length=7) {
         $characters = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
         $cLength = strlen($characters);
         $string = '';

test/ark/ArkManagerTest.php

@@ -63,4 +63,12 @@ class ArkManagerTest extends \PHPUnit_Framework_TestCase {
             $this->assertNotContains($ark, $arks, "Ark was found to repeat: " . $ark);
         }
     }
+
+    /**
+     * Minting a real ark cannot be tested in production
+    public function testMintRealArk() {
+        $ark = $this->am->mintArk();
+        $this->assertNotFalse($ark);
+    }
+    **/
 }