Google OAuth Device Flow support for FNL

examples/authentication_demo/google_authentication_demo.cc

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/bind.h"
+#include "base/logging.h"
+#include "mojo/public/c/system/main.h"
+#include "mojo/public/cpp/application/application_connection.h"
+#include "mojo/public/cpp/application/application_delegate.h"
+#include "mojo/public/cpp/application/application_impl.h"
+#include "mojo/public/cpp/application/application_runner.h"
+#include "mojo/public/cpp/utility/run_loop.h"
+#include "mojo/services/authentication/interfaces/authentication.mojom.h"
+
+namespace examples {
+namespace authentication {
+
+class GoogleAuthApp : public mojo::ApplicationDelegate {
+ public:
+  GoogleAuthApp() {}
+
+  ~GoogleAuthApp() override {}
+
+  void Initialize(mojo::ApplicationImpl* app) override {
+    DLOG(INFO) << "Connecting to authentication service...";
+    app->ConnectToService("mojo:authentication", &authentication_service_);
+
+    mojo::Array<mojo::String> scopes;
+    scopes.push_back("profile");
+    scopes.push_back("email");
+
+    DLOG(INFO) << "Starting the device flow handshake...";
+    authentication_service_->GetOAuth2DeviceCode(
+        scopes.Pass(),
+        base::Bind(&GoogleAuthApp::OnDeviceCode, base::Unretained(this)));
+  }
+
+ private:
+  void OnDeviceCode(const mojo::String& url,
+                    const mojo::String& device_code,
+                    const mojo::String& user_code,
+                    const mojo::String& error) {
+    if (!error.is_null()) {
+      DLOG(INFO) << "Error: " << error;
+      mojo::RunLoop::current()->Quit();  // All done!
+      return;
+    }
+    // Display the verification url and user code in system UI and ask the
+    // user to authorize in a companion device
+    DLOG(INFO) << "Verification Url: " << url;
+    DLOG(INFO) << "Device Code: " << device_code;
+    DLOG(INFO) << "User Code: " << user_code;
+    DLOG(INFO) << "Waiting for user autorization on a secondary device...";
+
+    // Poll and exchange the user authorization to a long lived token
+    DLOG(INFO) << "...";
+    AddAccount(device_code);
+  }
+
+  // Exchange device code to a refresh token, and persist the grant.
+  void AddAccount(const std::string device_code) {
+    authentication_service_->AddAccount(
+        device_code,
+        base::Bind(&GoogleAuthApp::OnAddAccount, base::Unretained(this)));
+  }
+
+  void OnAddAccount(const mojo::String& username, const mojo::String& error) {
+    if (!error.is_null() || username.is_null()) {
+      DLOG(INFO) << "Missing username or Error: " << error;
+      mojo::RunLoop::current()->Quit();  // All done!
+      return;
+    }
+
+    DLOG(INFO) << "Successfully registered user: " << username;
+    DLOG(INFO) << "Fetching access token for user [" << username << "]...";
+    FetchOAuth2AccessToken();
+  }
+
+  // Fetch a new access token for an existing user grant.
+  void FetchOAuth2AccessToken() {
+    authentication_service_->SelectAccount(
+        true,
+        base::Bind(&GoogleAuthApp::OnSelectAccount, base::Unretained(this)));
+  }
+
+  // Selects an existing user account for this app based on previous
+  // authorization.
+  void OnSelectAccount(const mojo::String& username,
+                       const mojo::String& error) {
+    if (!error.is_null()) {
+      DLOG(INFO) << "Error: " << error;
+      mojo::RunLoop::current()->Quit();  // All done!
+      return;
+    }
+
+    DLOG(INFO) << "Selected <user> for this app: " << username;
+
+    mojo::Array<mojo::String> scopes;
+    scopes.push_back("profile");
+
+    authentication_service_->GetOAuth2Token(
+        username, scopes.Pass(),
+        base::Bind(&GoogleAuthApp::OnGetOAuth2Token, base::Unretained(this)));
+  }
+
+  void OnGetOAuth2Token(const mojo::String& access_token,
+                        const mojo::String& error) {
+    if (!error.is_null()) {
+      DLOG(INFO) << "Error: " << error;
+      mojo::RunLoop::current()->Quit();  // All done!
+      return;
+    }
+
+    if (access_token.is_null()) {
+      DLOG(INFO) << "Unable to fetch access token, exiting!";
+    } else {
+      DLOG(INFO) << "Access Token: " << access_token;
+    }
+    mojo::RunLoop::current()->Quit();  // All done!
+    return;
+  }
+
+  ::authentication::AuthenticationServicePtr authentication_service_;
+};
+
+}  // namespace authentication
+}  // namespace examples
+
+MojoResult MojoMain(MojoHandle application_request) {
+  mojo::ApplicationRunner runner(
+      std::unique_ptr<examples::authentication::GoogleAuthApp>(
+          new examples::authentication::GoogleAuthApp()));
+  return runner.Run(application_request);
+}