Add :messages command to show past messages.

This adds a 'level' query parameter to qute://log and qute://plainlog.
For example, qute://log?level=warning will show an html page containing
log entries with severity warning or greater.
If the query is omitted, the original behavior of qute://log is
preserved.

:messages [level] is a command that opens qute://log?level=<level>.
By default, level defaults to 'error' as an easy way to see missed
error messages.

qutebrowser/browser/commands.py

@@ -1339,6 +1339,22 @@ class CommandDispatcher:
         url = QUrl('qute://help/{}'.format(path))
         self._open(url, tab, bg, window)
 
+    @cmdutils.register(instance='command-dispatcher', scope='window')
+    def messages(self, level='error', plain=False, tab=False, bg=False,
+                 window=False):
+        """Show a log of past messages.
+
+        Args:
+            level: Include messages with `level` or higher severity.
+                   Valid values: vdebug, debug, info, warning, error, critical.
+            plain: Whether to show plaintext (as opposed to html).
+        """
+        if plain:
+            url = QUrl('qute://plainlog?level={}'.format(level))
+        else:
+            url = QUrl('qute://log?level={}'.format(level))
+        self._open(url, tab, bg, window)
+
     @cmdutils.register(instance='command-dispatcher',
                        modes=[KeyMode.insert], hide=True, scope='window')
     def open_editor(self):

qutebrowser/browser/network/qutescheme.py

@@ -27,7 +27,7 @@ import functools
 import configparser
 import mimetypes
 
-from PyQt5.QtCore import pyqtSlot, QObject
+from PyQt5.QtCore import pyqtSlot, QObject, QUrlQuery
 from PyQt5.QtNetwork import QNetworkReply
 
 import qutebrowser
@@ -159,22 +159,37 @@ def qute_version(_win_id, _request):
 
 @add_handler('plainlog')
 def qute_plainlog(_win_id, _request):
-    """Handler for qute:plainlog. Return HTML content as bytes."""
+    """Handler for qute:plainlog. Return HTML content as bytes.
+
+    An optional query parameter specifies the min log level to print.
+    For example, qute://log?level=warning prints warnings and errors.
+    Level can be one of: vdebug, debug, info, warning, error, critical.
+    """
     if log.ram_handler is None:
         text = "Log output was disabled."
     else:
-        text = log.ram_handler.dump_log()
+        query = QUrlQuery(_request.url().query())
+        level = query.queryItemValue('level')
+        text = log.ram_handler.dump_log(html=False, level=level)
     html = jinja.render('pre.html', title='log', content=text)
     return html.encode('UTF-8', errors='xmlcharrefreplace')
 
 
 @add_handler('log')
 def qute_log(_win_id, _request):
-    """Handler for qute:log. Return HTML content as bytes."""
+    """Handler for qute:log. Return HTML content as bytes.
+
+    An optional query parameter specifies the min log level to print.
+    For example, qute://log?level=warning prints warnings and errors.
+    Level can be one of: vdebug, debug, info, warning, error, critical.
+    """
     if log.ram_handler is None:
         html_log = None
     else:
-        html_log = log.ram_handler.dump_log(html=True)
+        query = QUrlQuery(_request.url().query())
+        level = query.queryItemValue('level')
+        html_log = log.ram_handler.dump_log(html=True, level=level)
+
     html = jinja.render('log.html', title='log', content=html_log)
     return html.encode('UTF-8', errors='xmlcharrefreplace')
 

qutebrowser/utils/log.py

@@ -429,13 +429,15 @@ class RAMHandler(logging.Handler):
             # We don't log VDEBUG to RAM.
             self._data.append(record)
 
-    def dump_log(self, html=False):
+    def dump_log(self, html=False, level='vdebug'):
         """Dump the complete formatted log data as as string.
 
         FIXME: We should do all the HTML formatter via jinja2.
         (probably obsolete when moving to a widget for logging,
         https://github.com/The-Compiler/qutebrowser/issues/34
         """
+        # pylint: disable=protected-access
+        minlevel = logging._nameToLevel.get(level.upper(), VDEBUG_LEVEL)
         lines = []
         fmt = self.html_formatter.format if html else self.format
         self.acquire()
@@ -444,7 +446,8 @@ class RAMHandler(logging.Handler):
         finally:
             self.release()
         for record in records:
-            lines.append(fmt(record))
+            if record.levelno >= minlevel:
+                lines.append(fmt(record))
         return '\n'.join(lines)
 
 

tests/integration/features/misc.feature

@@ -342,7 +342,7 @@ Feature: Various utility commands.
     Scenario: Running :pyeval with --quiet
         When I run :debug-pyeval --quiet 1+1
         Then "pyeval output: 2" should be logged
-        
+
     ## https://github.com/The-Compiler/qutebrowser/issues/504
 
     Scenario: Focusing download widget via Tab
@@ -367,3 +367,35 @@ Feature: Various utility commands.
         When I set network -> custom-headers to {"X-Qute-Test": "testvalue"}
         And I open headers
         Then the header X-Qute-Test should be set to testvalue
+
+    ## :messages
+
+    Scenario: Showing error messages
+        When I run :message-error the-error-message
+        And I run :message-warning the-warning-message
+        And I run :message-info the-info-message
+        And I run :messages
+        Then the error "the-error-message" should be shown
+        And the warning "the-warning-message" should be shown
+        And the page should contain the plaintext "the-error-message"
+
+    Scenario: Showing messages of type 'warning' or greater
+        When I run :message-error the-error-message
+        And I run :message-warning the-warning-message
+        And I run :message-info the-info-message
+        And I run :messages warning
+        Then the error "the-error-message" should be shown
+        And the warning "the-warning-message" should be shown
+        And the page should contain the plaintext "the-error-message"
+        And the page should contain the plaintext "the-warning-message"
+
+    Scenario: Showing messages of type 'info' or greater
+        When I run :message-error the-error-message
+        And I run :message-warning the-warning-message
+        And I run :message-info the-info-message
+        And I run :messages info
+        Then the error "the-error-message" should be shown
+        And the warning "the-warning-message" should be shown
+        And the page should contain the plaintext "the-error-message"
+        And the page should contain the plaintext "the-warning-message"
+        And the page should contain the plaintext "the-info-message"