added method in OAuth for add proper redirect url

Author: sergeysviridenko

README.md

@@ -20,6 +20,9 @@ switch to the relevant [branch][:branch:]/[tag][:tags:].
 
 The current version can be seen at [Phosphorum Wiki][:wiki:].
 
+## Github authorization
+Forum has possibility to authorize users with Github. Please set `GITHUB_CLIENT_ID`, `GITHUB_SECRET`, `GITHUB_REDIRECT_URI` parameters in your `.env` file.
+
 ## License
 
 Phosphorum is an open-sourced software licensed under the [New BSD License][:license:].<br>

app/library/Github/OAuth.php

@@ -46,10 +46,10 @@ class OAuth extends Injectable
      */
     public function __construct(Config $config)
     {
-        $this->redirectUriAuthorize = $config->get('redirectUri');
+        $this->logger               = $this->getDI()->get('logger', ['auth']);
+        $this->redirectUriAuthorize = $this->checkRedirectGitPath($config->get('redirectUri'));
         $this->clientId             = $config->get('clientId');
         $this->clientSecret         = $config->get('clientSecret');
-        $this->logger               = $this->getDI()->get('logger', ['auth']);
     }
 
     public function authorize()
@@ -132,4 +132,42 @@ public function send($url, $parameters, $method = 'post')
             return false;
         }
     }
+
+    /**
+     * @param string $url
+     *
+     * @return string
+     */
+    protected function checkRedirectGitPath($url)
+    {
+        if (empty($url)) {
+            $this->logger->error(
+                "Parameter GITHUB_REDIRECT_URI in .env file doesn't exist. Please, check setting in .env file and on Github."
+            );
+            return '';
+        }
+
+        if (!stristr($url, '://')) {
+            $this->logger->warning(
+                'Authorization callback URL is wrong. Please, check setting in .env file and on Github.'
+            );
+            return '';
+        }
+
+        if (stristr($url, '://', true) != $this->request->getScheme()) {
+            $this->logger->warning(
+                'HyperText Protocol in your application and in your setting file is different. Please, check setting in .env file and on Github.'
+            );
+            return '';
+        }
+
+        if (substr($url, -1) != '/') {
+            $this->logger->warning(
+                'Authorization callback URL should contain slash in the end. Please, check setting in .env file and on Github.'
+            );
+            return '';
+        }
+
+        return $url;
+    }
 }