Pipe: Experimental pipe-based IPC interface

bin/gpo

@@ -61,6 +61,7 @@
     rewrite OLDURL NEWURL      Change the feed URL of [OLDURL] to [NEWURL]
     webui [public]             Start gPodder's Web UI server
                                (public = listen on all network interfaces)
+    pipe                       Start gPodder in pipe-based IPC server mode
 
 """
 
@@ -113,6 +114,7 @@ import gpodder
 _ = gpodder.gettext
 N_ = gpodder.ngettext
 
+gpodder.images_folder = os.path.join(prefix, 'share', 'gpodder', 'images')
 gpodder.prefix = prefix
 
 # This is the command-line UI variant
@@ -584,6 +586,10 @@ class gPodderCli(object):
         else:
             webui.main(core=self.core)
 
+    def pipe(self):
+        from gpodder import pipe
+        pipe.main(core=self.core)
+
     def search(self, *terms):
         query = ' '.join(terms)
         if not query:

src/gpodder/pipe/__init__.py

@@ -0,0 +1,202 @@
+# -*- coding: utf-8 -*-
+#
+# gPodder - A media aggregator and podcast client
+# Copyright (c) 2005-2012 Thomas Perl and the gPodder Team
+#
+# gPodder is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# gPodder is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+# gpodder.pipe - Socket/pipe-based backend for New UIs
+# Thomas Perl <thp@gpodder.org>; 2012-11-24
+
+
+import gpodder
+
+from gpodder import core
+from gpodder import model
+from gpodder import util
+from gpodder import coverart
+
+try:
+    # For Python < 2.6, we use the "simplejson" add-on module
+    import simplejson as json
+except ImportError:
+    # Python 2.6 already ships with a nice "json" module
+    import json
+
+import os
+import re
+import sys
+import threading
+import Queue
+import time
+import fcntl
+
+def cmd(*signature):
+    def wrapper(f):
+        setattr(f, '_pipecmd', True)
+        return f
+    return wrapper
+
+def to_json(o):
+    keys = list(('id',) + o.__slots__)
+    values = list(getattr(o, key) for key in keys)
+    yield keys
+    yield values
+
+class PipeError(BaseException): pass
+
+class Pipe:
+    def __init__(self, core, reader, writer):
+        self.core = core
+
+        self.model = self.core.model
+        self.cover_download = coverart.CoverDownloader()
+
+        self.reader = reader
+        self.writer = writer
+        self.events_in = Queue.Queue()
+        self.events_out = Queue.Queue()
+
+    def event_writer_proc(self):
+        while True:
+            item = self.events_out.get(True)
+            self.writer.write(item.encode('utf-8') + '\n')
+            self.writer.flush()
+
+    def event_reader_proc(self):
+        while True:
+            args = self.events_in.get(True)
+            cmd = args.pop(0)
+            func = getattr(self, cmd, None)
+            if func is not None:
+                if getattr(func, '_pipecmd', False):
+                    try:
+                        result = func(*args)
+                        if result:
+                            self.event_out(result)
+                    except PipeError, e:
+                        self.event_out('! %s' % e)
+                    except Exception, e:
+                        print >>sys.stderr, 'FAIL:', e
+                        self.event_out('! %s' % e)
+                        raise
+                    continue
+
+            self.event_out('? %s' % line)
+
+    def event_in(self, data):
+        self.events_in.put(data)
+
+    def event_out(self, data):
+        self.events_out.put(data)
+
+    def find_episode(self, id):
+        for podcast in self.model.get_podcasts():
+            for episode in podcast.get_all_episodes():
+                if episode.id == int(id):
+                    return episode
+        raise PipeError('episode not found')
+
+    def find_podcast(self, id):
+        for podcast in self.model.get_podcasts():
+            if podcast.id == int(id):
+                return podcast
+        raise PipeError('podcast not found')
+
+    def summarize_podcasts(self, podcasts):
+        yield ('id', 'title', 'downloads', 'cover')
+        for podcast in podcasts:
+            total, deleted, new, downloaded, unplayed = podcast.get_statistics()
+            cover_filename = self.cover_download.get_cover(podcast.cover_file,
+                    podcast.cover_url, podcast.url, podcast.title,
+                    podcast.auth_username, podcast.auth_password, True)
+            yield (podcast.id, podcast.title, downloaded, cover_filename)
+
+    def summarize_episodes(self, episodes):
+        yield ('id', 'title', 'state')
+        for episode in episodes:
+            yield (episode.id, episode.title, episode.state)
+
+    def serialize(self, data):
+        return json.dumps(list(data), ensure_ascii=False)
+
+    @cmd()
+    def podcasts(self):
+        return 'podcasts ' + self.serialize(self.summarize_podcasts(self.model.get_podcasts()))
+
+    @cmd(int)
+    def episodes(self, id):
+        podcast = self.find_podcast(id)
+        return 'episodes ' + id + ' ' + self.serialize(self.summarize_episodes(podcast.get_all_episodes()))
+
+    @cmd(int)
+    def episode(self, id):
+        episode = self.find_episode(id)
+        return 'episode ' + id + ' ' + self.serialize(to_json(episode))
+
+    @cmd(int)
+    def podcast(self, id):
+        podcast = self.find_podcast(id)
+        return 'podcast ' + id + ' ' + self.serialize(to_json(podcast))
+
+    @cmd()
+    def update_all(self):
+        @util.run_in_background
+        def update_proc():
+            for podcast in self.model.get_podcasts():
+                self.event_out('updating %d' % podcast.id)
+                podcast.update()
+                self.event_out('updated %d' % podcast.id)
+            self.event_out('updated_all')
+
+    @cmd(int)
+    def update(self, id):
+        @util.run_in_background
+        def update_proc():
+            podcast = self.find_podcast(id)
+            self.event_out('updating %d' % podcast.id)
+            podcast.update()
+            self.event_out('updated %d' % podcast.id)
+
+    def run(self):
+        def post_random_events():
+            while True:
+                time.sleep(1)
+                self.event_out('hello')
+                time.sleep(2)
+                self.event_out('hello 10')
+        random_event_thread = threading.Thread(target=post_random_events)
+        random_event_thread.setDaemon(True)
+        #random_event_thread.start()
+
+        reader_thread = threading.Thread(target=self.event_reader_proc)
+        writer_thread = threading.Thread(target=self.event_writer_proc)
+        reader_thread.setDaemon(True)
+        writer_thread.setDaemon(True)
+        reader_thread.start()
+        writer_thread.start()
+
+        while True:
+            line = self.reader.readline()
+            if not line:
+                break
+            line = line.rstrip()
+            if line:
+                self.event_in(line.split())
+
+def main(core):
+    pipe = Pipe(core, sys.stdin, sys.stdout)
+    pipe.run()
+