Add site specific quirks

WhatsApp Web:
See #4445

Google Accounts:
See #5147

Slack:
See #4669 (With older QtWebEngine versions, Slack refuses to work, despite
it (seemingly) working fine.)

Dell Support

Google Docs:
See #4805 and https://bugreports.qt.io/browse/QTBUG-69652
Note that the default UA with Chrome/... shows a "browser not supported"
warning.

Fixes #4810

5 files changed, 69 insertions, 1 deletions

diff --git a/doc/changelog.asciidoc b/doc/changelog.asciidoc
index 573cb5018..c9e5ccc3c 100644
--- a/doc/changelog.asciidoc
+++ b/doc/changelog.asciidoc
@@ -28,6 +28,9 @@ Added
   - `fonts.contextmenu`
   - `colors.contextmenu.bg`
   - `colors.contextmenu.fg`
+- New `content.site_specific_quirks` setting which enables workarounds for
+  websites with broken user agent parsing (enabled by default, see the "Fixed"
+  section for fixed websites).
 
 Changed
 ~~~~~~~
@@ -94,6 +97,12 @@ Fixed
   - `url.open_base_url = True` together with `url.auto_search = 'never'` is now
     handled correctly.
   - Fixed crash when a search engine URL turns out to be invalid.
+- Site specific quirks which work around some broken websites:
+  - WhatsApp Web
+  - Google Accounts
+  - Slack (with older QtWebEngine versions)
+  - Dell.com support pages (with Qt 5.7)
+  - Google Docs (fixes broken IME/compose key)
 
 v1.8.3 (2019-12-05)
 -------------------
diff --git a/doc/help/settings.asciidoc b/doc/help/settings.asciidoc
index 35fae2b53..d48706ac9 100644
--- a/doc/help/settings.asciidoc
+++ b/doc/help/settings.asciidoc
@@ -168,6 +168,7 @@
 |<<content.proxy,content.proxy>>|Proxy to use.
 |<<content.proxy_dns_requests,content.proxy_dns_requests>>|Send DNS requests over the configured proxy.
 |<<content.register_protocol_handler,content.register_protocol_handler>>|Allow websites to register protocol handlers via `navigator.registerProtocolHandler`.
+|<<content.site_specific_quirks,content.site_specific_quirks>>|Enable quirks (such as faked user agent headers) needed to get specific sites to work properly.
 |<<content.ssl_strict,content.ssl_strict>>|Validate SSL handshakes.
 |<<content.user_stylesheets,content.user_stylesheets>>|List of user stylesheet filenames to use.
 |<<content.webgl,content.webgl>>|Enable WebGL.
@@ -2222,6 +2223,15 @@ On QtWebEngine, this setting requires Qt 5.11 or newer.
 
 On QtWebKit, this setting is unavailable.
 
+[[content.site_specific_quirks]]
+=== content.site_specific_quirks
+Enable quirks (such as faked user agent headers) needed to get specific sites to work properly.
+This setting requires a restart.
+
+Type: <<types,Bool>>
+
+Default: +pass:[true]+
+
 [[content.ssl_strict]]
 === content.ssl_strict
 Validate SSL handshakes.
diff --git a/qutebrowser/browser/webengine/webenginesettings.py b/qutebrowser/browser/webengine/webenginesettings.py
index 4a677539f..fcdbd7d7e 100644
--- a/qutebrowser/browser/webengine/webenginesettings.py
+++ b/qutebrowser/browser/webengine/webenginesettings.py
@@ -35,7 +35,8 @@ from PyQt5.QtWebEngineWidgets import (QWebEngineSettings, QWebEngineProfile,
 from qutebrowser.browser.webengine import spell, webenginequtescheme
 from qutebrowser.config import config, websettings
 from qutebrowser.config.websettings import AttributeInfo as Attr
-from qutebrowser.utils import utils, standarddir, qtutils, message, log
+from qutebrowser.utils import (utils, standarddir, qtutils, message, log,
+                               urlmatch)
 
 # The default QWebEngineProfile
 default_profile = typing.cast(QWebEngineProfile, None)
@@ -329,6 +330,41 @@ def _init_profiles():
         private_profile.setter.init_profile()
 
 
+def _init_site_specific_quirks():
+    if not config.val.content.site_specific_quirks:
+        return
+
+    # default_ua = ("Mozilla/5.0 ({os_info}) "
+    #               "AppleWebKit/{webkit_version} (KHTML, like Gecko) "
+    #               "{qt_key}/{qt_version} "
+    #               "{upstream_browser_key}/{upstream_browser_version} "
+    #               "Safari/{webkit_version}")
+    no_qtwe_ua = ("Mozilla/5.0 ({os_info}) "
+                  "AppleWebKit/{webkit_version} (KHTML, like Gecko) "
+                  "{upstream_browser_key}/{upstream_browser_version} "
+                  "Safari/{webkit_version}")
+    firefox_ua = "Mozilla/5.0 ({os_info}; rv:71.0) Gecko/20100101 Firefox/71.0"
+    new_chrome_ua = ("Mozilla/5.0 ({os_info}) "
+                     "AppleWebKit/537.36 (KHTML, like Gecko) "
+                     "Chrome/99 "
+                     "Safari/537.36")
+
+    user_agents = {
+        'https://web.whatsapp.com/': no_qtwe_ua,
+        'https://accounts.google.com/ServiceLogin': firefox_ua,
+        'https://*.slack.com/*': new_chrome_ua,
+        'https://docs.google.com/*': firefox_ua,
+    }
+
+    if not qtutils.version_check('5.9'):
+        user_agents['https://www.dell.com/support/*'] = new_chrome_ua
+
+    for pattern, ua in user_agents.items():
+        config.instance.set_obj('content.headers.user_agent', ua,
+                                pattern=urlmatch.UrlPattern(pattern),
+                                hide_userconfig=True)
+
+
 def init(args):
     """Initialize the global QWebSettings."""
     if (args.enable_webengine_inspector and
@@ -345,6 +381,8 @@ def init(args):
     global_settings = WebEngineSettings(_SettingsWrapper())
     global_settings.init_settings()
 
+    _init_site_specific_quirks()
+
 
 def shutdown():
     pass
diff --git a/qutebrowser/browser/webkit/webkitsettings.py b/qutebrowser/browser/webkit/webkitsettings.py
index f5e55607d..74b8a49a8 100644
--- a/qutebrowser/browser/webkit/webkitsettings.py
+++ b/qutebrowser/browser/webkit/webkitsettings.py
@@ -82,6 +82,8 @@ class WebKitSettings(websettings.AbstractSettings):
             Attr(QWebSettings.PrintElementBackgrounds),
         'content.xss_auditing':
             Attr(QWebSettings.XSSAuditingEnabled),
+        'content.site_specific_quirks':
+            Attr(QWebSettings.SiteSpecificQuirksEnabled),
 
         'input.spatial_navigation':
             Attr(QWebSettings.SpatialNavigationEnabled),
diff --git a/qutebrowser/config/configdata.yml b/qutebrowser/config/configdata.yml
index 8316835a8..2d8d37e47 100644
--- a/qutebrowser/config/configdata.yml
+++ b/qutebrowser/config/configdata.yml
@@ -395,6 +395,15 @@ content.frame_flattening:
 
     This will flatten all the frames to become one scrollable page.
 
+content.site_specific_quirks:
+  default: true
+  restart: true
+  type: Bool
+  desc: 'Enable quirks (such as faked user agent headers) needed to get
+      specific sites to work properly.'
+
+# emacs: '
+
 content.geolocation:
   default: ask
   type: BoolAsk