fix member_added/member_removed event with tests and and provide a group-tracking example

python/examples/group_tracking.py

@@ -0,0 +1,64 @@
+
+# content of group_tracking.py
+
+import sys
+import optparse
+import deltachat
+
+
+class GroupTrackingPlugin:
+    @deltachat.hookspec.account_hookimpl
+    def process_incoming_message(self, message):
+        print("*** process_incoming_message addr={} msg={!r}".format(
+              message.get_sender_contact().addr, message.text))
+        for member in message.chat.get_contacts():
+            print("chat member: {}".format(member.addr))
+
+    @deltachat.hookspec.account_hookimpl
+    def member_added(self, chat, contact):
+        print("*** member_added", contact.addr, "from", chat)
+        for member in chat.get_contacts():
+            print("chat member: {}".format(member.addr))
+
+    @deltachat.hookspec.account_hookimpl
+    def member_removed(self, chat, contact):
+        print("*** member_removed", contact.addr, "from", chat)
+
+
+def main(argv):
+    p = optparse.OptionParser("simple-echo")
+    p.add_option("-l", action="store_true", help="show ffi")
+    p.add_option("--db", type="str", help="database file")
+    p.add_option("--email", type="str", help="email address")
+    p.add_option("--password", type="str", help="password")
+
+    opts, posargs = p.parse_args(argv)
+
+    assert opts.db, "you must specify --db"
+    ac = deltachat.Account(opts.db)
+
+    if opts.l:
+        log = deltachat.eventlogger.FFIEventLogger(ac, "group-tracking")
+        ac.add_account_plugin(log)
+
+    if not ac.is_configured():
+        assert opts.email and opts.password, (
+            "you must specify --email and --password"
+        )
+        ac.set_config("addr", opts.email)
+        ac.set_config("mail_pw", opts.password)
+        ac.set_config("mvbox_watch", "0")
+        ac.set_config("sentbox_watch", "0")
+
+    ac.add_account_plugin(GroupTrackingPlugin())
+
+    # start IO threads and configure if neccessary
+    ac.start()
+
+    print("{}: waiting for message".format(ac.get_config("addr")))
+
+    ac.wait_shutdown()
+
+
+if __name__ == "__main__":
+    main(sys.argv)