Adding a signals panel to display list of signals and their providing arguments

and receivers.  Thanks Alex Gaynor!

Signed-off-by: Rob Hudson <rob@cogit8.org>

5 files changed, 101 insertions, 2 deletions

diff --git a/README.rst b/README.rst
index 22a89ea..c80e005 100644
--- a/README.rst
+++ b/README.rst
@@ -15,6 +15,7 @@ Currently, the following panels have been written and are working:
 - GET/POST/cookie/session variable display
 - Templates and context used, and their template paths
 - SQL queries including time to execute and links to EXPLAIN each query
+- List of signals, their args and receivers
 - Logging output via Python's built-in logging module
 
 If you have ideas for other panels please let us know.
@@ -50,7 +51,7 @@ Installation
 
 #. Add `debug_toolbar` to your `INSTALLED_APPS` setting so Django can find the
    template files associated with the Debug Toolbar.
-   
+
    Alternatively, add the path to the debug toolbar templates
    (``'path/to/debug_toolbar/templates'`` to your ``TEMPLATE_DIRS`` setting.)
 
@@ -72,6 +73,7 @@ The debug toolbar has two settings that can be set in `settings.py`:
 	    'debug_toolbar.panels.request_vars.RequestVarsDebugPanel',
 	    'debug_toolbar.panels.template.TemplateDebugPanel',
 	    'debug_toolbar.panels.sql.SQLDebugPanel',
+	    'debug_toolbar.panels.signals.SignalDebugPanel',
 	    'debug_toolbar.panels.logger.LoggingPanel',
 	)
 
@@ -96,6 +98,9 @@ The debug toolbar has two settings that can be set in `settings.py`:
      provide your own method for displaying the toolbar which contains your
      custom logic.  This method should return True or False.
 
+   * `EXTRA_SIGNALS`: An array of custom signals that might be in your project,
+     defined as the python path to the signal.
+
    Example configuration::
 
 	def custom_show_toolbar(request):
@@ -104,6 +109,7 @@ The debug toolbar has two settings that can be set in `settings.py`:
 	DEBUG_TOOLBAR_CONFIG = {
 	    'INTERCEPT_REDIRECTS': False,
 	    'SHOW_TOOLBAR_CALLBACK': custom_show_toolbar,
+	    'EXTRA_SIGNALS': ['myproject.signals.MySignal'],
 	}
 
 TODOs and BUGS
diff --git a/debug_toolbar/panels/signals.py b/debug_toolbar/panels/signals.py
new file mode 100644
index 0000000..0a75282
--- /dev/null
+++ b/debug_toolbar/panels/signals.py
@@ -0,0 +1,73 @@
+import sys
+
+from django.conf import settings
+from django.core.signals import request_started, request_finished, \
+    got_request_exception
+from django.db.backends.signals import connection_created
+from django.db.models.signals import class_prepared, pre_init, post_init, \
+    pre_save, post_save, pre_delete, post_delete, post_syncdb
+from django.dispatch.dispatcher import WEAKREF_TYPES
+from django.template.loader import render_to_string
+
+from debug_toolbar.panels import DebugPanel
+
+class SignalDebugPanel(DebugPanel):
+    name = "Signals"
+    has_content = True
+
+    SIGNALS = {
+        'request_started': request_started,
+        'request_finished': request_finished,
+        'got_request_exception': got_request_exception,
+        'connection_created': connection_created,
+        'class_prepared': class_prepared,
+        'pre_init': pre_init,
+        'post_init': post_init,
+        'pre_save': pre_save,
+        'post_save': post_save,
+        'pre_delete': pre_delete,
+        'post_delete': post_delete,
+        'post_syncdb': post_syncdb,
+    }
+
+    def title(self):
+        return "Signals"
+
+    def url(self):
+        return ''
+
+    def signals(self):
+        signals = self.SIGNALS.copy()
+        if hasattr(settings, 'DEBUG_TOOLBAR_CONFIG'):
+            extra_signals = settings.DEBUG_TOOLBAR_CONFIG.get('EXTRA_SIGNALS', [])
+        else:
+            extra_signals = []
+        for signal in extra_signals:
+            parts = signal.split('.')
+            path = '.'.join(parts[:-1])
+            __import__(path)
+            signals[parts[-1]] = getattr(sys.modules[path], parts[-1])
+        return signals
+    signals = property(signals)
+
+    def content(self):
+        signals = []
+        keys = self.signals.keys()
+        keys.sort()
+        for name in keys:
+            signal = self.signals[name]
+            receivers = []
+            for (receiverkey, r_senderkey), receiver in signal.receivers:
+                if isinstance(receiver, WEAKREF_TYPES):
+                    receiver = receiver()
+                if receiver is None:
+                    continue
+                if getattr(receiver, 'im_self', None) is not None:
+                    text = "method %s on %s object" % (receiver.__name__, receiver.im_self.__class__.__name__)
+                elif getattr(receiver, 'im_class', None) is not None:
+                    text = "method %s on %s" % (receiver.__name__, receiver.im_class.__name__)
+                else:
+                    text = "function %s" % receiver.__name__
+                receivers.append(text)
+            signals.append((name, signal, receivers))
+        return render_to_string('debug_toolbar/panels/signals.html', {'signals': signals})
diff --git a/debug_toolbar/panels/sql.py b/debug_toolbar/panels/sql.py
index 8934fb3..d3ac7f3 100644
--- a/debug_toolbar/panels/sql.py
+++ b/debug_toolbar/panels/sql.py
@@ -98,7 +98,7 @@ class SQLDebugPanel(DebugPanel):
         return render_to_string('debug_toolbar/panels/sql.html', context)
 
 def reformat_sql(sql):
-    sql = sql.replace('`,`', '`, `')
+    sql = sql.replace(',', ', ')
     sql = sql.replace('SELECT ', 'SELECT\n\t')
     sql = sql.replace(' FROM ', '\nFROM\n\t')
     sql = sql.replace(' WHERE ', '\nWHERE\n\t')
diff --git a/debug_toolbar/templates/debug_toolbar/panels/signals.html b/debug_toolbar/templates/debug_toolbar/panels/signals.html
new file mode 100644
index 0000000..e9a189e
--- /dev/null
+++ b/debug_toolbar/templates/debug_toolbar/panels/signals.html
@@ -0,0 +1,19 @@
+<h3>Signals</h3>
+<table>
+    <thead>
+        <tr>
+            <th>Signal</th>
+            <th>Providing Args</th>
+            <th>Receivers</th>
+        </tr>
+    </thead>
+    <tbody>
+        {% for name, signal, receivers in signals %}
+            <tr class="{% cycle 'djDebugOdd' 'djDebugEven' %}">
+                <td>{{ name|escape }}</td>
+                <td>{{ signal.providing_args|join:", " }}</td>
+                <td>{{ receivers|join:", " }}</td>
+            </tr>
+        {% endfor %}
+    </tbody>
+</table>
diff --git a/debug_toolbar/toolbar/loader.py b/debug_toolbar/toolbar/loader.py
index 39fb4c6..c7f999e 100644
--- a/debug_toolbar/toolbar/loader.py
+++ b/debug_toolbar/toolbar/loader.py
@@ -21,6 +21,7 @@ class DebugToolbar(object):
             'debug_toolbar.panels.sql.SQLDebugPanel',
             'debug_toolbar.panels.template.TemplateDebugPanel',
             #'debug_toolbar.panels.cache.CacheDebugPanel',
+            'debug_toolbar.panels.signals.SignalDebugPanel',
             'debug_toolbar.panels.logger.LoggingPanel',
         )
         self.load_panels()