[tor-commits] [stem/master] Interpretor event handling

[atagar at torproject.org]

commit e4ea4f64e19c53a85414294f5b446d10cce4a074
Author: Damian Johnson <atagar at torproject.org>
Date:   Tue Apr 15 09:42:54 2014 -0700

    Interpretor event handling
    
    Supporting SETEVENTS and an '/event [type]' interpretor command for listing the
    events we've received.
---
 stem/interpretor/commands.py  |   42 ++++++++++++++++++++++++++++++++++++++++-
 stem/interpretor/settings.cfg |    6 ++++++
 2 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/stem/interpretor/commands.py b/stem/interpretor/commands.py
index af1948c..c711ade 100644
--- a/stem/interpretor/commands.py
+++ b/stem/interpretor/commands.py
@@ -47,6 +47,7 @@ SIGNAL_DESCRIPTIONS = (
 
 HELP_OPTIONS = {
   'HELP': ("/help [OPTION]", 'help.help'),
+  'EVENTS': ("/events [types]", 'help.events'),
   'QUIT': ("/quit", 'help.quit'),
   'GETINFO': ("GETINFO OPTION", 'help.getinfo'),
   'GETCONF': ("GETCONF OPTION", 'help.getconf'),
@@ -196,6 +197,14 @@ class ControlInterpretor(object):
 
   def __init__(self, controller):
     self.controller = controller
+    self.received_events = []
+
+  def register_event(self, event):
+    """
+    Adds the event to our buffer so it'll be in '/events' output.
+    """
+
+    self.received_events.append(event)
 
   def do_help(self, arg):
     """
@@ -317,6 +326,21 @@ class ControlInterpretor(object):
 
     return output
 
+  def do_events(self, arg):
+    """
+    Performs the '/events' operation, dumping the events that we've received
+    belonging to the given types. If no types are specified then this provides
+    all buffered events.
+    """
+
+    events = self.received_events
+    event_types = arg.upper().split()
+
+    if event_types:
+      events = filter(lambda event: event.type in event_types, events)
+
+    return '\n'.join([format(str(event), *OUTPUT_FORMAT) for event in events])
+
   def run_command(self, command):
     """
     Runs the given command. Requests starting with a '/' are special commands
@@ -356,6 +380,8 @@ class ControlInterpretor(object):
     if cmd.startswith('/'):
       if cmd == "/quit":
         raise stem.SocketClosed()
+      elif cmd == "/events":
+        output = self.do_events(arg)
       elif cmd == "/help":
         output = self.do_help(arg)
       else:
@@ -411,7 +437,21 @@ class ControlInterpretor(object):
         except stem.ControllerError as exc:
           output = format(str(exc), *ERROR_FORMAT)
       elif cmd == 'SETEVENTS':
-        pass  # TODO: implement
+        try:
+          # first discontinue listening to prior events
+
+          self.controller.remove_event_listener(self.register_event)
+
+          # attach listeners for the given group of events
+
+          if arg:
+            events = arg.split()
+            self.controller.add_event_listener(self.register_event, *events)
+            output = format('Listing for %s events\n' % ', '.join(events), *OUTPUT_FORMAT)
+          else:
+            output = format('Disabled event listening\n', *OUTPUT_FORMAT)
+        except stem.ControllerError as exc:
+          output = format(str(exc), *ERROR_FORMAT)
       elif cmd.replace('+', '') in ('LOADCONF', 'POSTDESCRIPTOR'):
         # provides a notice that multi-line controller input isn't yet implemented
         output = format(msg('msg.multiline_unimplemented_notice'), *ERROR_FORMAT)
diff --git a/stem/interpretor/settings.cfg b/stem/interpretor/settings.cfg
index 9cd2201..e93b0e8 100644
--- a/stem/interpretor/settings.cfg
+++ b/stem/interpretor/settings.cfg
@@ -15,6 +15,7 @@ help.takeownership Instructs Tor to gracefully shut down when this control conne
 help.general
 |Interpretor commands include:
 |  /help   - provides information for interpretor and tor commands/config options
+|  /events - prints events that we've received
 |  /quit   - shuts down the interpretor
 |
 |Tor commands include:
@@ -48,6 +49,11 @@ help.help
 |Example:
 |  /help GETINFO     # usage information for tor's GETINFO controller option
 
+help.events
+|Provides events that we've received belonging to the given event types. If
+|no types are specified then this provides all the messages that we've
+|received.
+
 help.getinfo
 |Queries the tor process for information. Options are...
 |