* added wormhole and logging modules.

lastfm/api.py

@@ -7,6 +7,7 @@ __license__ = "GNU Lesser General Public License"
 __package__ = "lastfm"
 
 from threading import Lock
+from lastfm.util import Wormhole, logging
 from lastfm.decorators import cached_property, async_callback
 _lock = Lock()
 
@@ -23,6 +24,12 @@ class Api(object):
     """The minimum interval between successive HTTP request, in seconds"""
     
     SEARCH_XMLNS = "http://a9.com/-/spec/opensearch/1.1/"
+    
+    DEBUG_LEVELS = {
+        'LOW': 1,
+        'MEDIUM': 2,
+        'HIGH': 3
+    }
 
     def __init__(self,
                  api_key,
@@ -31,7 +38,8 @@ class Api(object):
                  input_encoding=None,
                  request_headers=None,
                  no_cache = False,
-                 debug = False):
+                 debug = None,
+                 logfile = None):
         """
         Create an Api object to access the last.fm webservice API. Use this object as a
         starting point for accessing all the webservice methods.
@@ -64,8 +72,19 @@ class Api(object):
         self._initialize_user_agent()
         self._input_encoding = input_encoding
         self._no_cache = no_cache
-        self._debug = debug
+        self._logfile = logfile
         self._last_fetch_time = datetime.now()
+        
+        if debug is not None:
+            if debug in Api.DEBUG_LEVELS:
+                self._debug = Api.DEBUG_LEVELS[debug]
+            else:
+                raise InvalidParametersError("debug parameter must be one of the keys in Api.DEBUG_LEVELS dict")
+        else:
+            self._debug = None
+        if self._debug is not None:
+            Wormhole.enable()
+            logging.set_api(self)
 
     @property
     def api_key(self):
@@ -588,6 +607,7 @@ class Api(object):
         """
         return Venue.search(self, search_item = venue, limit = limit, country = country)
 
+    @Wormhole.entrance('lfm-api-url')
     def _build_url(self, url, path_elements=None, extra_params=None):
         # Break url into consituent parts
         (scheme, netloc, path, params, query, fragment) = urlparse.urlparse(url)
@@ -656,11 +676,10 @@ class Api(object):
             self._last_fetch_time = datetime.now()
         return url_data
 
+    @Wormhole.entrance('lfm-api-raw-data')
     def _fetch_url(self, url, parameters = None, no_cache = False):
         # Add key/value parameters to the query string of the url
         url = self._build_url(url, extra_params=parameters)
-        if self._debug:
-            print url
         # Get a url opener that can handle basic auth
         opener = self._get_opener(url)
 
@@ -690,6 +709,7 @@ class Api(object):
         # Always return the latest version
         return url_data
 
+    @Wormhole.entrance('lfm-api-processed-data')
     def _fetch_data(self,
                    params,
                    sign = False,
@@ -710,17 +730,17 @@ class Api(object):
         xml = self._fetch_url(Api.API_ROOT_URL, params, no_cache = self._no_cache or no_cache)
         return self._check_xml(xml)
 
+    @Wormhole.entrance('lfm-api-raw-data')
     def _post_url(self,
                  url,
                  parameters):
         url = self._build_url(url)
         data = self._encode_parameters(parameters)
-        if self._debug:
-            print data
         opener = self._get_opener(url)
         url_data = self._read_url_data(opener, url, data)
         return url_data
 
+    @Wormhole.entrance('lfm-api-processed-data')
     def _post_data(self, params):
         params['api_key'] = self.api_key
 

lastfm/chart.py

@@ -8,6 +8,7 @@ __package__ = "lastfm"
 from functools import reduce
 from lastfm.base import LastfmBase
 from lastfm.mixin import cacheable
+from lastfm.util import logging
 from operator import xor
 
 @cacheable
@@ -404,8 +405,8 @@ class RollingChart(Chart):
             try:
                 period_wacl.append(
                     getattr(subject, "get_weekly_%s_chart" % chart_type)(wc.start, wc.end))
-            except LastfmError:
+            except LastfmError as ex:
-                pass
+                logging.log_silenced_exceptions(ex)
         stats_dict = period_wacl[0].__dict__["_%ss" % chart_type][0].stats.__dict__
         count_attribute = [k for k in stats_dict.keys()
                            if stats_dict[k] is not None and k not in ['_rank', '_subject']][0]

lastfm/mixin/_chartable.py

@@ -5,7 +5,7 @@ __version__ = "0.2"
 __license__ = "GNU Lesser General Public License"
 __package__ = "lastfm.mixin"
 
-from lastfm.util import lazylist
+from lastfm.util import lazylist, logging
 from lastfm.decorators import cached_property
 
 def chartable(chart_types):
@@ -83,8 +83,8 @@ def chartable(chart_types):
                 for wc in wcl:
                     try:
                         yield self.get_weekly_album_chart(wc.start, wc.end)
-                    except LastfmError:
+                    except LastfmError as ex:
-                        pass
+                        logging.log_silenced_exceptions(ex)
             return gen()
         
         def get_monthly_album_chart(self, start = None, end = None):
@@ -104,8 +104,8 @@ def chartable(chart_types):
                 for mc in mcl:
                     try:
                         yield self.get_monthly_album_chart(mc.start, mc.end)
-                    except LastfmError:
+                    except LastfmError as ex:
-                        pass
+                        logging.log_silenced_exceptions(ex)
             return gen()
     
         def get_quaterly_album_chart(self, start = None, end = None):
@@ -179,8 +179,8 @@ def chartable(chart_types):
                 for wc in wcl:
                     try:
                         yield self.get_weekly_artist_chart(wc.start, wc.end)
-                    except LastfmError:
+                    except LastfmError as ex:
-                        pass
+                        logging.log_silenced_exceptions(ex)
             return gen()
         
         def get_monthly_artist_chart(self, start = None, end = None):
@@ -200,8 +200,8 @@ def chartable(chart_types):
                 for mc in mcl:
                     try:
                         yield self.get_monthly_artist_chart(mc.start, mc.end)
-                    except LastfmError:
+                    except LastfmError as ex:
-                        pass
+                        logging.log_silenced_exceptions(ex)
             return gen()
     
         def get_quaterly_artist_chart(self, start = None, end = None):
@@ -275,8 +275,8 @@ def chartable(chart_types):
                 for wc in wcl:
                     try:
                         yield self.get_weekly_track_chart(wc.start, wc.end)
-                    except LastfmError:
+                    except LastfmError as ex:
-                        pass
+                        logging.log_silenced_exceptions(ex)
             return gen()
         
         def get_monthly_track_chart(self, start = None, end = None):
@@ -296,8 +296,8 @@ def chartable(chart_types):
                 for mc in mcl:
                     try:
                         yield self.get_monthly_track_chart(mc.start, mc.end)
-                    except LastfmError:
+                    except LastfmError as ex:
-                        pass
+                        logging.log_silenced_exceptions(ex)
             return gen()
     
         def get_quaterly_track_chart(self, start = None, end = None):
@@ -373,8 +373,8 @@ def chartable(chart_types):
                 for wc in wcl:
                     try:
                         yield self.get_weekly_tag_chart(wc.start, wc.end)
-                    except LastfmError:
+                    except LastfmError as ex:
-                        pass
+                        logging.log_silenced_exceptions(ex)
             return gen()
         
         def get_monthly_tag_chart(self, start = None, end = None):
@@ -394,8 +394,8 @@ def chartable(chart_types):
                 for mc in mcl:
                     try:
                         yield self.get_monthly_tag_chart(mc.start, mc.end)
-                    except LastfmError:
+                    except LastfmError as ex:
-                        pass
+                        logging.log_silenced_exceptions(ex)
             return gen()
         
         def get_quaterly_tag_chart(self, start = None, end = None):

lastfm/util/logging.py

@@ -0,0 +1,65 @@
+#!/usr/bin/env python
+
+__author__ = "Abhinav Sarkar <abhinav@abhinavsarkar.net>"
+__version__ = "0.2"
+__license__ = "GNU Lesser General Public License"
+__package__ = "lastfm.util"
+
+from contextlib import contextmanager, nested
+from threading import Lock
+from lastfm.util import Wormhole
+from datetime import datetime
+import sys
+
+api = None
+lock = Lock()
+
+def set_api(api_):
+    global api
+    api = api_
+
+@contextmanager
+def logfile():
+    if api._logfile is None:
+        try:
+            yield sys.stdout
+        finally:
+            pass
+    else:
+        try:
+            log = None
+            try:
+                log = open(api._logfile, 'at')
+                yield log
+            except IOError:
+                sys.stderr.write("could not open log file, logging to stdout\n")
+                yield sys.stdout
+        finally:
+            if log is not None:
+                log.close()
+
+@Wormhole.exit('lfm-api-url')
+def log_url(url, *args, **kwargs):
+    if api._debug >= api.DEBUG_LEVELS['LOW']:
+        with nested(logfile(), lock) as (log, l):
+            log.write("{0}: URL fetched: {1}\n".format(datetime.now(), url))
+        
+@Wormhole.exit('lfm-obcache-register')
+def log_object_registration((inst, already_registered), *args, **kwargs):
+    if api._debug >= api.DEBUG_LEVELS['MEDIUM']:
+        with nested(logfile(), lock) as (log, l):
+            if already_registered:
+                log.write("{0}: already registered: {1}\n".format(datetime.now(), repr(inst)))
+            else:
+                log.write("{0}: not already registered: {1}\n".format(datetime.now(), inst.__class__))
+
+@Wormhole.exit('lfm-api-raw-data')
+def log_raw_data(raw_data, *args, **kwargs):
+    if api._debug >= api.DEBUG_LEVELS['HIGH']:
+        with nested(logfile(), lock) as (log, l):
+            log.write("{0}: RAW DATA\n {1}\n".format(datetime.now(), raw_data))
+            
+def log_silenced_exceptions(ex):
+    if api._debug >= api.DEBUG_LEVELS['LOW']:
+        with nested(logfile(), lock) as (log, l):
+            log.write("{0}: Silenced Exception: {1}\n".format(datetime.now(), ex))

lastfm/util/objectcache.py

@@ -4,6 +4,8 @@ __author__ = "Abhinav Sarkar <abhinav@abhinavsarkar.net>"
 __version__ = "0.2"
 __license__ = "GNU Lesser General Public License"
 __package__ = "lastfm.util"
+
+from lastfm.util import Wormhole
     
 _registry = {}
 
@@ -24,6 +26,7 @@ class ObjectCache(object):
             ]
     
     @staticmethod
+    @Wormhole.entrance('lfm-obcache-register')
     def register(ob, key):
         cls_name = ob.__class__.__name__
         if not cls_name in _registry:

lastfm/util/wormhole.py

@@ -0,0 +1,89 @@
+#!/usr/bin/env python
+
+__author__ = "Abhinav Sarkar <abhinav@abhinavsarkar.net>"
+__version__ = "0.2"
+__license__ = "GNU Lesser General Public License"
+__package__ = "lastfm.util"
+
+from collections import defaultdict
+from decorator import decorator
+from threading import Lock
+
+_lock = Lock()
+
+class Wormhole(object):
+    _entrances = defaultdict(set)
+    _exits = defaultdict(set)
+    _enabled = False
+    
+    @staticmethod
+    def disable():
+        with _lock:
+            Wormhole._enabled = False
+        
+    @staticmethod
+    def enable():
+        with _lock:
+            Wormhole._enabled = True
+    
+    @staticmethod
+    def add_entrance(topic, entrance):
+        wrapped = Wormhole.entrance(topic)(entrance)
+        wrapped._orginal = entrance
+        return wrapped
+    
+    @staticmethod
+    def add_exit(topic, exit):
+        Wormhole._exits[topic].add(exit)
+    
+    @staticmethod
+    def remove_entrance(topic, entrance):
+        entrance = entrance._orginal
+        if topic in Wormhole._entrances:
+            if entrance in Wormhole._entrances[topic]:
+                Wormhole._entrances[topic].remove(entrance)
+        return entrance
+    
+    @staticmethod
+    def remove_exit(topic, exit):
+        if topic in Wormhole._exits:
+            if exit in Wormhole._exits[topic]:
+                Wormhole._exits[topic].remove(exit)
+    
+    @classmethod
+    def entrance(cls, topic):
+        @decorator
+        def wrapper(func, *args, **kwargs):
+            Wormhole._entrances[topic].add(func)
+            retval = func(*args, **kwargs)
+            if topic in Wormhole._exits:
+                if Wormhole._enabled:
+                    if func in Wormhole._entrances[topic]:
+                        cls._jump(topic, retval, *args, **kwargs)
+            return retval
+        return wrapper
+    
+    @staticmethod
+    def exit(topic):
+        def wrapper(func):
+            Wormhole._exits[topic].add(func)
+            return func
+        return wrapper
+    
+    @staticmethod
+    def _jump(topic, retval, *args, **kwargs):
+        exceptions = []
+        for f in Wormhole._exits[topic]:
+            try:
+                f(retval, *args, **kwargs)
+            except Exception as e:
+                exceptions.append(e)
+        for e in exceptions:
+            raise e
+        
+class ThreadedWormhole(Wormhole):
+    @staticmethod
+    def _jump(topic, retval, *args, **kwargs):
+        import threading
+        for f in Wormhole._exits[topic]:
+            threading.Thread(target = lambda: f(retval, *args, **kwargs)).start()