feat: started Dropbox OAuth Support

app/config/providers.php

@@ -46,9 +46,9 @@ return [
         'icon' => 'icon-linkedin',
         'enabled' => true,
     ],
-    'reddit' => [
-        'developers' => 'https://www.reddit.com/dev/api/',
-        'icon' => 'icon-reddit',
+    'dropbox' => [
+        'developers' => 'https://www.dropbox.com/developers/documentation',
+        'icon' => 'icon-dropbox',
         'enabled' => true,
     ],
 ];

src/Auth/OAuth/Dropbox.php

@@ -0,0 +1,132 @@
+<?php
+
+namespace Auth\OAuth;
+
+use Auth\OAuth;
+
+// Reference Material
+// https://www.dropbox.com/developers/reference/oauth-guide
+// https://www.dropbox.com/developers/documentation/http/documentation#users-get_current_account 
+class Dropbox extends OAuth
+{
+    /**
+     * @var array
+     */
+    protected $user = [];
+
+    /**
+     * @return string
+     */
+    public function getName(): string
+    {
+        return 'dropbox';
+    }
+    
+    /**
+     * @return string
+     */
+    public function getLoginURL(): string
+    {
+        return 'https://login.microsoftonline.com/common/oauth2/v2.0/authorize?'.
+            'client_id='.urlencode($this->appID).
+            '&redirect_uri='.urlencode($this->callback).
+            '&state='.urlencode(json_encode($this->state)).
+            '&scope=offline_access+user.read'.
+            '&response_type=code'.
+            '&response_mode=query';
+    }
+
+    /**
+     * @param string $code
+     *
+     * @return string
+     */
+    public function getAccessToken(string $code): string
+    {
+        $headers[] = 'Content-Type: application/x-www-form-urlencoded';
+
+        $accessToken = $this->request(
+            'POST',
+            'https://login.microsoftonline.com/common/oauth2/v2.0/token',
+            $headers,
+            'code='.urlencode($code).
+            '&client_id='.urlencode($this->appID).
+            '&client_secret='.urlencode($this->appSecret).
+            '&redirect_uri='.urlencode($this->callback).
+            '&scope=offline_access+user.read'.
+            '&grant_type=authorization_code'
+        );
+
+        $accessToken = json_decode($accessToken, true);
+
+        if (isset($accessToken['access_token'])) {
+            return $accessToken['access_token'];
+        }
+
+        return '';
+    }
+
+    /**
+     * @param string $accessToken
+     *
+     * @return string
+     */
+    public function getUserID(string $accessToken): string
+    {
+        $user = $this->getUser($accessToken);
+
+        if (isset($user['id'])) {
+            return $user['id'];
+        }
+
+        return '';
+    }
+
+    /**
+     * @param string $accessToken
+     *
+     * @return string
+     */
+    public function getUserEmail(string $accessToken): string
+    {
+        $user = $this->getUser($accessToken);
+
+        if (isset($user['userPrincipalName'])) {
+            return $user['userPrincipalName'];
+        }
+
+        return '';
+    }
+
+    /**
+     * @param string $accessToken
+     *
+     * @return string
+     */
+    public function getUserName(string $accessToken): string
+    {
+        $user = $this->getUser($accessToken);
+
+        if (isset($user['displayName'])) {
+            return $user['displayName'];
+        }
+
+        return '';
+    }
+
+    /**
+     * @param string $accessToken
+     *
+     * @return array
+     */
+    protected function getUser(string $accessToken): array
+    {
+        if (empty($this->user)) {
+            $headers[] = 'Authorization: Bearer '. urlencode($accessToken);
+            $user = $this->request('GET', 'https://graph.microsoft.com/v1.0/me', $headers);
+            $this->user = json_decode($user, true);
+        }
+
+        return $this->user;
+    }
+}