Add refreshToken method

src/Two/AbstractProvider.php

@@ -340,6 +340,33 @@ protected function getTokenFields($code)
         return $fields;
     }
 
+    /**
+     * Refresh a user access token with a refresh token.
+     *
+     * @param  string  $refreshToken
+     * @return Token
+     */
+    public function refreshToken($refreshToken)
+    {
+        $response = $this->getHttpClient()->post($this->getTokenUrl(), [
+            RequestOptions::HEADERS => ['Accept' => 'application/json'],
+            RequestOptions::FORM_PARAMS => [
+                'grant_type' => 'refresh_token',
+                'refresh_token' => $refreshToken,
+                'client_id' => $this->clientId,
+                'client_secret' => $this->clientSecret,
+            ]
+        ]);
+
+        $response = json_decode($response->getBody(), true);
+
+        return (new Token)
+            ->setToken(Arr::get($response, 'access_token'))
+            ->setRefreshToken(Arr::get($response, 'refresh_token'))
+            ->setExpiresIn(Arr::get($response, 'expires_in'))
+            ->setApprovedScopes(explode($this->scopeSeparator, Arr::get($response, 'scope', '')));
+    }
+
     /**
      * Get the code from the request.
      *

src/Two/Token.php

@@ -0,0 +1,86 @@
+<?php
+
+namespace Laravel\Socialite\Two;
+
+class Token
+{
+    /**
+     * The user's access token.
+     *
+     * @var string
+     */
+    public $token;
+
+    /**
+     * The refresh token that can be exchanged for a new access token.
+     *
+     * @var string
+     */
+    public $refreshToken;
+
+    /**
+     * The number of seconds the access token is valid for.
+     *
+     * @var int
+     */
+    public $expiresIn;
+
+    /**
+     * The scopes the user authorized. The approved scopes may be a subset of the requested scopes.
+     *
+     * @var array
+     */
+    public $approvedScopes;
+
+    /**
+     * Set the token on the user.
+     *
+     * @param  string  $token
+     * @return $this
+     */
+    public function setToken($token)
+    {
+        $this->token = $token;
+
+        return $this;
+    }
+
+    /**
+     * Set the refresh token required to obtain a new access token.
+     *
+     * @param  string  $refreshToken
+     * @return $this
+     */
+    public function setRefreshToken($refreshToken)
+    {
+        $this->refreshToken = $refreshToken;
+
+        return $this;
+    }
+
+    /**
+     * Set the number of seconds the access token is valid for.
+     *
+     * @param  int  $expiresIn
+     * @return $this
+     */
+    public function setExpiresIn($expiresIn)
+    {
+        $this->expiresIn = $expiresIn;
+
+        return $this;
+    }
+
+    /**
+     * Set the scopes that were approved by the user during authentication.
+     *
+     * @param  array  $approvedScopes
+     * @return $this
+     */
+    public function setApprovedScopes($approvedScopes)
+    {
+        $this->approvedScopes = $approvedScopes;
+
+        return $this;
+    }
+}

tests/OAuthTwoTest.php

@@ -10,6 +10,7 @@
 use Laravel\Socialite\Tests\Fixtures\OAuthTwoTestProviderStub;
 use Laravel\Socialite\Tests\Fixtures\OAuthTwoWithPKCETestProviderStub;
 use Laravel\Socialite\Two\InvalidStateException;
+use Laravel\Socialite\Two\Token;
 use Laravel\Socialite\Two\User;
 use Mockery as m;
 use PHPUnit\Framework\TestCase;
@@ -178,4 +179,23 @@ public function testExceptionIsThrownIfStateIsNotSet()
         $provider = new OAuthTwoTestProviderStub($request, 'client_id', 'client_secret', 'redirect');
         $provider->user();
     }
+
+    public function testUserRefreshesToken()
+    {
+        $request = Request::create('/');
+        $provider = new OAuthTwoTestProviderStub($request, 'client_id', 'client_secret', 'redirect_uri');
+        $provider->http = m::mock(stdClass::class);
+        $provider->http->expects('post')->with('http://token.url', [
+            'headers' => ['Accept' => 'application/json'],
+            'form_params' => ['grant_type' => 'refresh_token', 'client_id' => 'client_id', 'client_secret' => 'client_secret', 'refresh_token' => 'refresh_token'],
+        ])->andReturns($response = m::mock(stdClass::class));
+        $response->expects('getBody')->andReturns('{ "access_token" : "access_token", "refresh_token" : "refresh_token", "expires_in" : 3600, "scope" : "scope1,scope2" }');
+        $tokenResponse = $provider->refreshToken('refresh_token');
+
+        $this->assertInstanceOf(Token::class, $tokenResponse);
+        $this->assertSame('access_token', $tokenResponse->token);
+        $this->assertSame('refresh_token', $tokenResponse->refreshToken);
+        $this->assertSame(3600, $tokenResponse->expiresIn);
+        $this->assertSame(['scope1', 'scope2'], $tokenResponse->approvedScopes);
+    }
 }