Merge pull request #3 from DutchCodingCompany/feature/authorization_code_grant

Feature/authorization code grant

Author: Bas de Vaan

lib/src/oauth_grant.dart

@@ -45,4 +45,37 @@ class ClientCredentialsGrant extends OAuthGrant {
   }
 }
 
-//TODO: Add AuthorizationCodeGrant
+/// Obtains credentials using a [authorization code grant](https://tools.ietf.org/html/rfc6749#section-1.3.1).
+class AuthorizationCodeGrant extends OAuthGrant {
+  const AuthorizationCodeGrant({
+    required this.tokenEndpoint,
+    required this.scopes,
+    required this.redirectUrl,
+    required this.redirect,
+    required this.listen,
+  });
+
+  final Uri tokenEndpoint;
+  final Uri redirectUrl;
+  final List<String> scopes;
+  final Future<void> Function(Uri authorizationUri) redirect;
+  final Future<Uri> Function(Uri redirectUri) listen;
+
+  @override
+  Future<String> handle(
+      Uri authorizationEndpoint, String identifier, String secret) async {
+    final grant = oauth.AuthorizationCodeGrant(
+      identifier,
+      authorizationEndpoint,
+      tokenEndpoint,
+    );
+    var authorizationUrl =
+        grant.getAuthorizationUrl(redirectUrl, scopes: scopes);
+    await redirect(authorizationUrl);
+    var responseUrl = await listen(redirectUrl);
+    oauth.Client client =
+        await grant.handleAuthorizationResponse(responseUrl.queryParameters);
+
+    return client.credentials.toJson();
+  }
+}

test/oauth_authenticator_test.dart

@@ -23,8 +23,10 @@ void main() {
     ),
   );
   final testRequest = Request('GET', Uri(host: 'test'), Uri(host: 'test'));
-  final unauthorizedResponse = Response(http.Response('body', HttpStatus.unauthorized), 'body');
-  final authorizedResponse = Response(http.Response('body', HttpStatus.accepted), 'body');
+  final unauthorizedResponse =
+      Response(http.Response('body', HttpStatus.unauthorized), 'body');
+  final authorizedResponse =
+      Response(http.Response('body', HttpStatus.accepted), 'body');
 
   test('only refresh on unauthorized and token', () async {
     // arrange
@@ -34,7 +36,8 @@ void main() {
     final expected = {'Authorization': 'Bearer token'};
 
     // act
-    final result = await authenticator.authenticate(testRequest, unauthorizedResponse);
+    final result =
+        await authenticator.authenticate(testRequest, unauthorizedResponse);
 
     // assert
     verify(mockOAuthChopper.refresh()).called(1);
@@ -48,7 +51,8 @@ void main() {
     final authenticator = OAuthAuthenticator(mockOAuthChopper, null);
 
     // act
-    final result = await authenticator.authenticate(testRequest, authorizedResponse);
+    final result =
+        await authenticator.authenticate(testRequest, authorizedResponse);
 
     // assert
     verifyNever(mockOAuthChopper.refresh());
@@ -62,7 +66,8 @@ void main() {
     final authenticator = OAuthAuthenticator(mockOAuthChopper, null);
 
     // act
-    final result = await authenticator.authenticate(testRequest, unauthorizedResponse);
+    final result =
+        await authenticator.authenticate(testRequest, unauthorizedResponse);
 
     // assert
     verifyNever(mockOAuthChopper.refresh());
@@ -76,7 +81,8 @@ void main() {
     final authenticator = OAuthAuthenticator(mockOAuthChopper, null);
 
     // act
-    final result = await authenticator.authenticate(testRequest, unauthorizedResponse);
+    final result =
+        await authenticator.authenticate(testRequest, unauthorizedResponse);
 
     // assert
     verify(mockOAuthChopper.refresh()).called(1);
@@ -91,18 +97,23 @@ void main() {
 
     // act
     // assert
-    expect(() async => await authenticator.authenticate(testRequest, unauthorizedResponse), throwsFormatException);
+    expect(
+        () async =>
+            await authenticator.authenticate(testRequest, unauthorizedResponse),
+        throwsFormatException);
   });
 
   test("Exception not thrown if onError is supplied", () async {
     // arrange
     FormatException? result;
     when(mockOAuthChopper.refresh()).thenThrow(FormatException('failed'));
     when(mockOAuthChopper.token).thenAnswer((_) async => testToken);
-    final authenticator = OAuthAuthenticator(mockOAuthChopper, (e, s) => result = e as FormatException);
+    final authenticator = OAuthAuthenticator(
+        mockOAuthChopper, (e, s) => result = e as FormatException);
 
     // act
-    final responseResult = await authenticator.authenticate(testRequest, unauthorizedResponse);
+    final responseResult =
+        await authenticator.authenticate(testRequest, unauthorizedResponse);
 
     // assert
     expect(result?.message, 'failed');