Allow getting repo info by id, not just user and repo name (#579)

* Get repo details by id

* Updating doc for showById

* Adding note that this is an undocumented feature

* Adding test for showById()

* Stating undocumented in the docs too

Author: violuke

doc/repos.md

@@ -44,10 +44,18 @@ $repos = $client->api('repo')->find('chess', array('language' => 'php', 'start_p
 
 ### Get extended information about a repository
 
+Using the username of the repository owner and the repository name:
+
 ```php
 $repo = $client->api('repo')->show('KnpLabs', 'php-github-api')
 ```
 
+Or by using the repository id (note that this is at time of writing an undocumented feature, see [here](https://github.com/piotrmurach/github/issues/283) and [here](https://github.com/piotrmurach/github/issues/282)):
+
+```php
+$repo = $client->api('repo')->showById(123456)
+```
+
 Returns an array of information about the specified repository.
 
 ### Get the repositories of a specific user

lib/Github/Api/Repo.php

@@ -150,6 +150,23 @@ public function show($username, $repository)
     {
         return $this->get('/repos/'.rawurlencode($username).'/'.rawurlencode($repository));
     }
+    
+    /**
+     * Get extended information about a repository by its id.
+     * Note: at time of writing this is an undocumented feature but GitHub support have advised that it can be relied on.
+     *
+     * @link http://developer.github.com/v3/repos/
+     * @link https://github.com/piotrmurach/github/issues/283
+     * @link https://github.com/piotrmurach/github/issues/282
+     *
+     * @param int $id   the id of the repository
+     *
+     * @return array information about the repository
+     */
+    public function showById($id)
+    {
+        return $this->get('/repositories/'.rawurlencode($id));
+    }
 
     /**
      * Create repository.

test/Github/Tests/Api/RepoTest.php

@@ -19,6 +19,22 @@ public function shouldShowRepository()
 
         $this->assertEquals($expectedArray, $api->show('KnpLabs', 'php-github-api'));
     }
+    
+    /**
+     * @test
+     */
+    public function shouldShowRepositoryById()
+    {
+        $expectedArray = array('id' => 123456, 'name' => 'repoName');
+
+        $api = $this->getApiMock();
+        $api->expects($this->once())
+            ->method('get')
+            ->with('/repositories/123456')
+            ->will($this->returnValue($expectedArray));
+
+        $this->assertEquals($expectedArray, $api->showById(123456));
+    }
 
     /**
      * @test