Be more forgiving when validating URLs. Fixes #141.

doc/HACKING.asciidoc

@@ -421,7 +421,8 @@ displaying it to the user.
 * Mention in the docstring whether your function needs a URL string or a
 `QUrl`.
 * Call `ensure_valid` from `utils.qtutils` whenever getting or creating a
-`QUrl` and take appropriate action if not.
+`QUrl` and take appropriate action if not. Note the URL of the current page
+always could be an invalid QUrl (if nothing is loaded yet).
 
 
 Style conventions

qutebrowser/browser/commands.py

@@ -92,6 +92,11 @@ class CommandDispatcher:
             tab: Whether to open in a new tab.
             background: Whether to open in the background.
         """
+        if not url.isValid():
+            errstr = "Invalid URL {}"
+            if url.errorString():
+                errstr += " - {}".format(url.errorString())
+            raise cmdexc.CommandError(errstr)
         tabbed_browser = objreg.get('tabbed-browser')
         if tab and background:
             raise cmdexc.CommandError("Only one of -t/-b can be given!")
@@ -715,9 +720,6 @@ class CommandDispatcher:
         """
         urlstr = quickmarks.get(name)
         url = QUrl(urlstr)
-        if not url.isValid():
-            raise cmdexc.CommandError("Invalid URL {} ({})".format(
-                urlstr, url.errorString()))
         self._open(url, tab, bg)
 
     @cmdutils.register(instance='command-dispatcher', name='inspector')

qutebrowser/browser/downloads.py

@@ -359,7 +359,9 @@ class DownloadManager(QObject):
             url: The URL to get, as QUrl
             page: The QWebPage to get the download from.
         """
-        qtutils.ensure_valid(url)
+        if not url.isValid():
+            urlutils.invalid_url_error(url, "start download")
+            return
         req = QNetworkRequest(url)
         reply = page.networkAccessManager().get(req)
         self.fetch(reply)

qutebrowser/browser/hints.py

@@ -327,7 +327,6 @@ class HintManager(QObject):
         Args:
             url: The URL to open as a QURL.
         """
-        qtutils.ensure_valid(url)
         sel = self._context.target == Target.yank_primary
         mode = QClipboard.Selection if sel else QClipboard.Clipboard
         urlstr = url.toString(QUrl.FullyEncoded | QUrl.RemovePassword)
@@ -341,7 +340,6 @@ class HintManager(QObject):
         Args:
             url: The URL to open as a QUrl.
         """
-        qtutils.ensure_valid(url)
         urlstr = url.toDisplayString(QUrl.FullyEncoded)
         args = self._context.get_args(urlstr)
         message.set_cmd_text(' '.join(args))
@@ -357,19 +355,16 @@ class HintManager(QObject):
             message.error("No suitable link found for this element.",
                           immediately=True)
             return
-        qtutils.ensure_valid(url)
         objreg.get('download-manager').get(url, elem.webFrame().page())
 
     def _call_userscript(self, url):
         """Call an userscript from a hint."""
-        qtutils.ensure_valid(url)
         cmd = self._context.args[0]
         args = self._context.args[1:]
         userscripts.run(cmd, *args, url=url)
 
     def _spawn(self, url):
         """Spawn a simple command from a hint."""
-        qtutils.ensure_valid(url)
         urlstr = url.toString(QUrl.FullyEncoded | QUrl.RemovePassword)
         args = self._context.get_args(urlstr)
         subprocess.Popen(args)
@@ -396,6 +391,7 @@ class HintManager(QObject):
             if baseurl is None:
                 baseurl = self._context.baseurl
             url = baseurl.resolved(url)
+        qtutils.ensure_valid(url)
         return url
 
     def _find_prevnext(self, frame, prev=False):
@@ -511,7 +507,6 @@ class HintManager(QObject):
         if url is None:
             raise cmdexc.CommandError("No {} links found!".format(
                 "prev" if prev else "forward"))
-        qtutils.ensure_valid(url)
         if newtab:
             objreg.get('tabbed-browser').tabopen(url, background=False)
         else:

qutebrowser/browser/quickmarks.py

@@ -64,7 +64,9 @@ def prompt_save(url):
     Args:
         url: The quickmark url as a QUrl.
     """
-    qtutils.ensure_valid(url)
+    if not url.isValid():
+        urlutils.invalid_url_error(url, "save quickmark")
+        return
     urlstr = url.toString(QUrl.RemovePassword | QUrl.FullyEncoded)
     message.ask_async("Add quickmark:", usertypes.PromptMode.text,
                       functools.partial(quickmark_add, urlstr))

qutebrowser/utils/urlutils.py

@@ -28,7 +28,7 @@ from PyQt5.QtCore import QUrl
 from PyQt5.QtNetwork import QHostInfo
 
 from qutebrowser.config import config
-from qutebrowser.utils import log, qtutils
+from qutebrowser.utils import log, qtutils, message
 
 
 # FIXME: we probably could raise some exceptions on invalid URLs
@@ -262,6 +262,17 @@ def qurl_from_user_input(urlstr):
         return QUrl('http://[{}]{}'.format(ipstr, rest))
 
 
+def invalid_url_error(url, action):
+    """Display an error message for an URL."""
+    if url.isValid():
+        raise ValueError("Calling invalid_url_error with valid URL {}".format(
+            url.toDisplayString()))
+    errstring = "Trying to {} with invalid URL".format(action)
+    if url.errorString():
+        errstring += " - {}".format(url.errorString())
+    message.error(errstring)
+
+
 class FuzzyUrlError(Exception):
 
     """Exception raised by fuzzy_url on problems."""

qutebrowser/widgets/tabbedbrowser.py

@@ -247,11 +247,13 @@ class TabbedBrowser(tabwidget.TabWidget):
             self._now_focused = None
         if tab is objreg.get('last-focused-tab', None):
             objreg.delete('last-focused-tab')
-        if not tab.cur_url.isEmpty():
+        if tab.cur_url.isValid():
-            qtutils.ensure_valid(tab.cur_url)
             history_data = qtutils.serialize(tab.history())
             entry = UndoEntry(tab.cur_url, history_data)
             self._undo_stack.append(entry)
+        else:
+            urlutils.invalid_url_error(url, "saving tab")
+            return
         tab.shutdown()
         self._tabs.remove(tab)
         self.removeTab(idx)

qutebrowser/widgets/webview.py

@@ -335,10 +335,13 @@ class WebView(QWebView):
 
     @pyqtSlot('QUrl')
     def on_url_changed(self, url):
-        """Update cur_url when URL has changed."""
+        """Update cur_url when URL has changed.
-        qtutils.ensure_valid(url)
+
-        self.cur_url = url
+        If the URL is invalid, we just ignore it here.
-        self.url_text_changed.emit(url.toDisplayString())
+        """
+        if url.isValid():
+            self.cur_url = url
+            self.url_text_changed.emit(url.toDisplayString())
 
     @pyqtSlot('QMouseEvent')
     def on_mouse_event(self, evt):