BrowserLogin: Add dedicated application mode to Rare for the webview login page

Add a sub-application to Rare to launch the webview for logging into EGS.
The sub-application operates similatly to the `laucher` sub-application and
it is autonomous. After a successful login in returns the exchange code
to the standard output to be parsed and used by the login dialog.

The reason this implementation was chosen is because when pywebview uses
pyqtwebengine as the GUI library, we cannot launch it through Rare as
it tries to spawn a QMainWindow inside an existing event loop, which is
prohibited by Qt.

Despite that, EGS login page doesn't work correctly with QtWebEngine,
so on linux default to the GTK backend for pywebview, and this change
helps keeping applications using different toolkits separate.

At this moment, spawning the sub-application blocks the execution of the
main application.

This change should make it easier to authenticate through Rare inside
a gamescope session, such as the steam deck.

rare/components/dialogs/login/browser_login.py

@@ -2,14 +2,15 @@ import json
 from logging import getLogger
 from typing import Tuple
 
-from PyQt5.QtCore import pyqtSignal, QUrl
+from PyQt5.QtCore import pyqtSignal, QUrl, QProcess, pyqtSlot
 from PyQt5.QtGui import QDesktopServices
 from PyQt5.QtWidgets import QFrame, qApp, QFormLayout, QLineEdit
-from legendary.core import LegendaryCore
 from legendary.utils import webview_login
 
+from rare.lgndr.core import LegendaryCore
 from rare.ui.components.dialogs.login.browser_login import Ui_BrowserLogin
 from rare.utils.misc import icon
+from rare.utils.paths import get_rare_executable
 from rare.widgets.indicator_edit import IndicatorLineEdit, IndicatorReasonsCommon
 
 logger = getLogger("BrowserLogin")
@@ -43,6 +44,7 @@ class BrowserLogin(QFrame):
         self.ui.open_button.clicked.connect(self.open_browser)
         self.sid_edit.textChanged.connect(self.changed.emit)
 
+    @pyqtSlot()
     def copy_link(self):
         clipboard = qApp.clipboard()
         clipboard.setText(self.login_url)
@@ -79,12 +81,24 @@ class BrowserLogin(QFrame):
         except Exception as e:
             logger.warning(e)
 
+    @pyqtSlot()
     def open_browser(self):
         if not webview_login.webview_available:
             logger.warning("You don't have webengine installed, you will need to manually copy the authorizationCode.")
             QDesktopServices.openUrl(QUrl(self.login_url))
         else:
-            if webview_login.do_webview_login(callback_code=self.core.auth_ex_token):
+            cmd = get_rare_executable() + ["login", self.core.get_egl_version()]
+            proc = QProcess(self)
+            proc.start(cmd[0], cmd[1:])
+            proc.waitForFinished(-1)
+            out, err = (
+                proc.readAllStandardOutput().data().decode("utf-8", "ignore"),
+                proc.readAllStandardError().data().decode("utf-8", "ignore")
+            )
+            proc.deleteLater()
+
+            if out:
+                self.core.auth_ex_token(out)
                 logger.info("Successfully logged in as %s", {self.core.lgd.userdata['displayName']})
                 self.success.emit()
             else:

rare/main.py

@@ -57,22 +57,26 @@ def main() -> int:
     )
     subparsers = parser.add_subparsers(title="Commands", dest="subparser")
 
-    launch_minimal_parser = subparsers.add_parser("start", aliases=["launch"])
-    launch_minimal_parser.add_argument("app_name", help="AppName of the game to launch",
-                                       metavar="<App Name>", action="store")
-    launch_minimal_parser.add_argument("--dry-run", help="Print arguments and exit", action="store_true")
-    launch_minimal_parser.add_argument("--offline", help="Launch game offline",
-                                       action="store_true")
-    launch_minimal_parser.add_argument('--wine-bin', dest='wine_bin', action='store', metavar='<wine binary>',
-                                       default=os.environ.get('LGDRY_WINE_BINARY', None),
-                                       help='Set WINE binary to use to launch the app')
-    launch_minimal_parser.add_argument('--wine-prefix', dest='wine_pfx', action='store', metavar='<wine pfx path>',
-                                       default=os.environ.get('LGDRY_WINE_PREFIX', None),
-                                       help='Set WINE prefix to use')
-    launch_minimal_parser.add_argument("--ask-sync-saves", help="Ask to sync cloud saves",
-                                       action="store_true")
-    launch_minimal_parser.add_argument("--skip-update-check", help="Do not check for updates",
-                                       action="store_true")
+    launch_parser = subparsers.add_parser("start", aliases=["launch"])
+    launch_parser.add_argument("app_name", help="AppName of the game to launch",
+                               metavar="<App Name>", action="store")
+    launch_parser.add_argument("--dry-run", help="Print arguments and exit", action="store_true")
+    launch_parser.add_argument("--offline", help="Launch game offline",
+                               action="store_true")
+    launch_parser.add_argument('--wine-bin', dest='wine_bin', action='store', metavar='<wine binary>',
+                               default=os.environ.get('LGDRY_WINE_BINARY', None),
+                               help='Set WINE binary to use to launch the app')
+    launch_parser.add_argument('--wine-prefix', dest='wine_pfx', action='store', metavar='<wine pfx path>',
+                               default=os.environ.get('LGDRY_WINE_PREFIX', None),
+                               help='Set WINE prefix to use')
+    launch_parser.add_argument("--ask-sync-saves", help="Ask to sync cloud saves",
+                               action="store_true")
+    launch_parser.add_argument("--skip-update-check", help="Do not check for updates",
+                               action="store_true")
+
+    login_parser = subparsers.add_parser("login", aliases=["auth"])
+    login_parser.add_argument("egl_version", help="Epic Games Launcher User Agent version",
+                              metavar="<EGL Version>", action="store")
 
     args = parser.parse_args()
 
@@ -93,6 +97,10 @@ def main() -> int:
         print(f"Rare {__version__} Codename: {__codename__}")
         return 0
 
+    if args.subparser in {"login", "auth"}:
+        from rare.webview import launch
+        return launch(args)
+
     if args.subparser in {"start", "launch"}:
         from rare.launcher import launch
         return launch(args)

rare/webview/__init__.py

@@ -0,0 +1,13 @@
+import sys
+from argparse import Namespace
+
+from legendary.utils import webview_login
+
+
+def launch(args: Namespace) -> int:
+    if webview_login.do_webview_login(
+            callback_code=sys.stdout.write, user_agent=f'EpicGamesLauncher/{args.egl_version}'
+    ):
+        return 0
+    else:
+        return 1

requirements-webview.txt

@@ -1,5 +1,6 @@
-pywebview[qt]; platform_system == "Linux"
-pywebview[qt]; platform_system == "FreeBSD"
+# pywebview with QtWebEngine backend has issues with EGS login form, so use GTK
+pywebview[gtk]; platform_system == "Linux"
+pywebview[gtk]; platform_system == "FreeBSD"
 pythonnet>=3.0.0rc4; platform_system == "Windows"
 cefpython3; platform_system == "Windows"
 pywebview[cef]; platform_system == "Windows"