Re-authenticate to Drive when token expires.

src/internet/googledriveclient.cpp

@@ -89,6 +89,7 @@ ConnectResponse* Client::Connect(const QString& refresh_token) {
 void Client::ConnectFinished(ConnectResponse* response, OAuthenticator* oauth) {
   oauth->deleteLater();
   access_token_ = oauth->access_token();
+  expiry_time_ = oauth->expiry_time();
   response->refresh_token_ = oauth->refresh_token();
   emit response->Finished();
 
@@ -186,3 +187,8 @@ void Client::GetFileFinished(GetFileResponse* response, QNetworkReply* reply) {
   response->file_ = File(result);
   emit response->Finished();
 }
+
+bool Client::is_authenticated() const {
+  return !access_token_.isEmpty() &&
+      QDateTime::currentDateTime().secsTo(expiry_time_) > 0;
+}

src/internet/googledriveclient.h

@@ -135,7 +135,7 @@ class Client : public QObject {
 public:
   Client(QObject* parent = 0);
 
-  bool is_authenticated() const { return !access_token_.isEmpty(); }
+  bool is_authenticated() const;
   const QString& access_token() const { return access_token_; }
 
   ConnectResponse* Connect(const QString& refresh_token = QString());
@@ -154,11 +154,12 @@ private:
   void AddAuthorizationHeader(QNetworkRequest* request) const;
   void MakeListFilesRequest(ListFilesResponse* response,
                             const QString& page_token = QString());
-  
+
 private:
   QNetworkAccessManager* network_;
 
   QString access_token_;
+  QDateTime expiry_time_;
 };
 
 } // namespace

src/internet/oauthenticator.cpp

@@ -18,6 +18,7 @@ namespace {
 const char* kGoogleOAuthEndpoint = "https://accounts.google.com/o/oauth2/auth";
 const char* kGoogleOAuthTokenEndpoint =
     "https://accounts.google.com/o/oauth2/token";
+const char* kGoogleOAuthScope = "https://www.googleapis.com/auth/drive.readonly";
 
 const char* kClientId = "679260893280.apps.googleusercontent.com";
 const char* kClientSecret = "l3cWb8efUZsrBI4wmY3uKl6i";
@@ -38,7 +39,7 @@ void OAuthenticator::StartAuthorisation() {
   url.addQueryItem("response_type", "code");
   url.addQueryItem("client_id", kClientId);
   url.addQueryItem("redirect_uri", QString("http://localhost:%1").arg(port));
-  url.addQueryItem("scope", "https://www.googleapis.com/auth/drive.readonly");
+  url.addQueryItem("scope", kGoogleOAuthScope);
 
   QDesktopServices::openUrl(url);
 }
@@ -157,6 +158,7 @@ void OAuthenticator::FetchAccessTokenFinished(QNetworkReply* reply) {
 
   access_token_ = result["access_token"].toString();
   refresh_token_ = result["refresh_token"].toString();
+  SetExpiryTime(result["expires_in"].toInt());
 
   emit Finished();
 }
@@ -187,6 +189,12 @@ void OAuthenticator::RefreshAuthorisation(const QString& refresh_token) {
              SLOT(RefreshAccessTokenFinished(QNetworkReply*)), reply);
 }
 
+void OAuthenticator::SetExpiryTime(int expires_in_seconds) {
+  // Set the expiry time with two minutes' grace.
+  expiry_time_ = QDateTime::currentDateTime().addSecs(expires_in_seconds - 120);
+  qLog(Debug) << "Current Google Drive token expires at:" << expiry_time_;
+}
+
 void OAuthenticator::RefreshAccessTokenFinished(QNetworkReply* reply) {
   reply->deleteLater();
   QJson::Parser parser;
@@ -194,5 +202,6 @@ void OAuthenticator::RefreshAccessTokenFinished(QNetworkReply* reply) {
 
   QVariantMap result = parser.parse(reply, &ok).toMap();
   access_token_ = result["access_token"].toString();
+  SetExpiryTime(result["expires_in"].toInt());
   emit Finished();
 }

src/internet/oauthenticator.h

@@ -1,6 +1,7 @@
 #ifndef OAUTHENTICATOR_H
 #define OAUTHENTICATOR_H
 
+#include <QDateTime>
 #include <QObject>
 #include <QTcpServer>
 
@@ -21,6 +22,8 @@ class OAuthenticator : public QObject {
   // Token to use to get a new access token when it expires.
   const QString& refresh_token() const { return refresh_token_; }
 
+  const QDateTime& expiry_time() const { return expiry_time_; }
+
  signals:
   void Finished();
 
@@ -33,12 +36,14 @@ class OAuthenticator : public QObject {
  private:
   QByteArray ParseHttpRequest(const QByteArray& request) const;
   void RequestAccessToken(const QByteArray& code, quint16 port);
+  void SetExpiryTime(int expires_in_seconds);
 
   QTcpServer server_;
   NetworkAccessManager network_;
 
   QString access_token_;
   QString refresh_token_;
+  QDateTime expiry_time_;
 };
 
 #endif