Add simple communication blocking (Fixes #1837)

- Add /block, /unblock, and /list_blocks commands
- Enable the commands only if the server advertises the feature
- http://xmpp.org/extensions/xep-0191.html#example-9 was not tested, but
  should work (could not find a server to test with)
- Add documentation for the commands

doc/en/usage.txt

@@ -436,6 +436,17 @@ Roster tab commands
  unsubscribe you from its presence, cancel its subscription to yours, and
  remove the item from your roster.
 
+NOTE: The following commands only exist if your server supports them. If it
+does not, you will be notified when you start poezio.
+
+*/block [jid]*:: Block the following JID using simple blocking. You will not
+ receive any of his messages and won’t be able to send some to him either.
+
+*/unblock [jid]*:: Unblock a previously blocked JID using simple blocking. You
+ will be able to send and receive messages from him again.
+
+*/list_blocks*:: List the blocked JIDs.
+
 NOTE: The following commands do not comply with any XEP or whatever, but they
  can still prove useful when you are migrating to an other JID.
 

src/connection.py

@@ -60,6 +60,7 @@ class Connection(sleekxmpp.ClientXMPP):
         self.register_plugin('xep_0048')
         self.register_plugin('xep_0071')
         self.register_plugin('xep_0085')
+        self.register_plugin('xep_0191')
         if config.get('send_poezio_info', 'true') == 'true':
             info = {'name':'poezio',
                     'version':'0.8-dev'}

src/tabs.py

@@ -39,7 +39,7 @@ import multiuserchat as muc
 
 from theming import get_theme
 
-from sleekxmpp.xmlstream.stanzabase import JID
+from sleekxmpp import JID, InvalidJID
 from sleekxmpp.xmlstream import matcher
 from sleekxmpp.xmlstream.handler import Callback
 from config import config
@@ -1859,10 +1859,126 @@ class RosterInfoTab(Tab):
         self.commands['export'] = (self.command_export, _("Usage: /export [/path/to/file]\nExport: Export your contacts into /path/to/file if specified, or $HOME/poezio_contacts if not."), self.completion_file)
         self.commands['import'] = (self.command_import, _("Usage: /import [/path/to/file]\nImport: Import your contacts from /path/to/file if specified, or $HOME/poezio_contacts if not."), self.completion_file)
         self.commands['clear_infos'] = (self.command_clear_infos, _("Usage: /clear_infos\nClear Infos: Use this command to clear the info buffer."), None)
+        self.core.xmpp.add_event_handler('session_start',
+                lambda event: self.core.xmpp.plugin['xep_0030'].get_info(
+                    jid=self.core.xmpp.boundjid.domain,
+                    block=False, timeout=5, callback=self.check_blocking)
+                )
         self.resize()
         self.update_commands()
         self.update_keys()
 
+    def check_blocking(self, iq):
+        if iq['type'] == 'error':
+            return
+        if 'urn:xmpp:blocking' in iq['disco_info'].get_features():
+            self.commands['block'] = (self.command_block, _("Usage: /block [jid]\nBlock: prevent a JID from talking to you."), self.completion_block)
+            self.commands['unblock'] = (self.command_unblock, _("Usage: /unblock [jid]\nUnblock: allow a JID to talk to you."), self.completion_unblock)
+            self.commands['list_blocks'] = (self.command_list_blocks, _("Usage: /list_blocks\nList Blocks: Retrieve the list of the blocked contacts."), None)
+            self.core.xmpp.del_event_handler('session_start', self.check_blocking)
+            self.core.xmpp.add_event_handler('blocked_message', self.on_blocked_message)
+        else:
+            self.core.information('Simple blocking not supported by the server', 'Info')
+
+    def on_blocked_message(self, message):
+        """
+        When we try to send a message to a blocked contact
+        """
+        tab = self.core.get_conversation_by_jid(message['from'], False)
+        if not tab:
+            log.debug('Received message from nonexistent tab: %s', message['from'])
+        message = '\x19%(info_col)s}Cannot send message to %(jid)s: contact blocked' % {
+                'info_col': get_theme().COLOR_INFORMATION_TEXT[0],
+                'jid': message['from'],
+            }
+        tab.add_message(message)
+
+    def command_block(self, arg):
+        """
+        /block [jid]
+        """
+        def callback(iq):
+            if iq['type'] == 'error':
+                return self.core.information('Could not block the contact.', 'Error')
+            elif iq['type'] == 'result':
+                return self.core.information('Contact blocked.', 'Info')
+
+        item = self.roster_win.selected_row
+        if arg:
+            try:
+                jid = JID(arg)
+            except InvalidJID:
+                self.core.information('JID not well-formed', 'Error')
+                return
+        elif isinstance(item, Contact):
+            jid = item.bare_jid
+        elif isinstance(item, Resource):
+            jid = item.jid.bare
+        self.core.xmpp.plugin['xep_0191'].block(jid, block=False, callback=callback)
+
+    def completion_block(self, the_input):
+        """
+        Completion for /block
+        """
+        jids = roster.jids()
+        return the_input.auto_completion(jids, '', quotify=False)
+
+    def command_unblock(self, arg):
+        """
+        /unblock [jid]
+        """
+        def callback(iq):
+            if iq['type'] == 'error':
+                return self.core.information('Could not unblock the contact.', 'Error')
+            elif iq['type'] == 'result':
+                return self.core.information('Contact unblocked.', 'Info')
+
+        item = self.roster_win.selected_row
+        if arg:
+            try:
+                jid = JID(arg)
+            except InvalidJID:
+                self.core.information('JID not well-formed', 'Error')
+                return
+        elif isinstance(item, Contact):
+            jid = item.bare_jid
+        elif isinstance(item, Resource):
+            jid = item.jid.bare
+        self.core.xmpp.plugin['xep_0191'].unblock(jid, block=False, callback=callback)
+
+    def completion_unblock(self, the_input):
+        """
+        Completion for /unblock
+        """
+        try:
+            iq = self.core.xmpp.plugin['xep_0191'].get_blocked(block=True)
+        except Exception as e:
+            iq = e.iq
+        finally:
+            if iq['type'] == 'error':
+                return
+            l = [str(item) for item in iq['blocklist']['items']]
+            return the_input.auto_completion(l, quotify=False)
+
+    def command_list_blocks(self, arg=None):
+        """
+        /list_blocks
+        """
+        def callback(iq):
+            if iq['type'] == 'error':
+                return self.core.information('Could not retrieve the blocklist.', 'Error')
+            s = 'List of blocked JIDs:\n'
+            log.debug('COCUCOCOCOCOCOCOC\n%s\n\n', iq['blocklist']['items'])
+            items = (str(item) for item in iq['blocklist']['items'])
+            jids = '\n'.join(items)
+            if jids:
+                s += jids
+            else:
+                s = 'No blocked JIDs.'
+            self.core.information(s, 'Info')
+
+        self.core.xmpp.plugin['xep_0191'].get_blocked(block=False, callback=callback)
+
     def resize(self):
         if not self.visible:
             return