bots: Move contrib_bots to api/bots*.

This will make it convenient to include these bots in Zulip API
releases on pypi.

Fix #5009.

bots_api/bot_lib.py

@@ -0,0 +1,177 @@
+from __future__ import print_function
+
+import logging
+import os
+import signal
+import sys
+import time
+import re
+
+if False:
+    from mypy_extensions import NoReturn
+from typing import Any, Optional, List, Dict
+from types import ModuleType
+
+our_dir = os.path.dirname(os.path.abspath(__file__))
+
+# For dev setups, we can find the API in the repo itself.
+if os.path.exists(os.path.join(our_dir, '../zulip')):
+    sys.path.insert(0, os.path.join(our_dir, '../'))
+
+from zulip import Client
+
+def exit_gracefully(signum, frame):
+    # type: (int, Optional[Any]) -> None
+    sys.exit(0)
+
+class RateLimit(object):
+    def __init__(self, message_limit, interval_limit):
+        # type: (int, int) -> None
+        self.message_limit = message_limit
+        self.interval_limit = interval_limit
+        self.message_list = [] # type: List[float]
+        self.error_message = '-----> !*!*!*MESSAGE RATE LIMIT REACHED, EXITING*!*!*! <-----\n'
+        'Is your bot trapped in an infinite loop by reacting to its own messages?'
+
+    def is_legal(self):
+        # type: () -> bool
+        self.message_list.append(time.time())
+        if len(self.message_list) > self.message_limit:
+            self.message_list.pop(0)
+            time_diff = self.message_list[-1] - self.message_list[0]
+            return time_diff >= self.interval_limit
+        else:
+            return True
+
+    def show_error_and_exit(self):
+        # type: () -> NoReturn
+        logging.error(self.error_message)
+        sys.exit(1)
+
+
+class BotHandlerApi(object):
+    def __init__(self, client):
+        # type: (Client) -> None
+        # Only expose a subset of our Client's functionality
+        user_profile = client.get_profile()
+        self._rate_limit = RateLimit(20, 5)
+        self._client = client
+        try:
+            self.full_name = user_profile['full_name']
+            self.email = user_profile['email']
+        except KeyError:
+            logging.error('Cannot fetch user profile, make sure you have set'
+                          ' up the zuliprc file correctly.')
+            sys.exit(1)
+
+    def send_message(self, message):
+        # type: (Dict[str, Any]) -> Dict[str, Any]
+        if self._rate_limit.is_legal():
+            return self._client.send_message(message)
+        else:
+            self._rate_limit.show_error_and_exit()
+
+    def update_message(self, message):
+        # type: (Dict[str, Any]) -> Dict[str, Any]
+        if self._rate_limit.is_legal():
+            return self._client.update_message(message)
+        else:
+            self._rate_limit.show_error_and_exit()
+
+    def send_reply(self, message, response):
+        # type: (Dict[str, Any], str) -> Dict[str, Any]
+        if message['type'] == 'private':
+            return self.send_message(dict(
+                type='private',
+                to=[x['email'] for x in message['display_recipient'] if self.email != x['email']],
+                content=response,
+            ))
+        else:
+            return self.send_message(dict(
+                type='stream',
+                to=message['display_recipient'],
+                subject=message['subject'],
+                content=response,
+            ))
+
+class StateHandler(object):
+    def __init__(self):
+        # type: () -> None
+        self.state = None # type: Any
+
+    def set_state(self, state):
+        # type: (Any) -> None
+        self.state = state
+
+    def get_state(self):
+        # type: () -> Any
+        return self.state
+
+def run_message_handler_for_bot(lib_module, quiet, config_file):
+    # type: (Any, bool, str) -> Any
+    #
+    # lib_module is of type Any, since it can contain any bot's
+    # handler class. Eventually, we want bot's handler classes to
+    # inherit from a common prototype specifying the handle_message
+    # function.
+    #
+    # Make sure you set up your ~/.zuliprc
+    client = Client(config_file=config_file)
+    restricted_client = BotHandlerApi(client)
+
+    message_handler = lib_module.handler_class()
+
+    state_handler = StateHandler()
+
+    if not quiet:
+        print(message_handler.usage())
+
+    def extract_query_without_mention(message, client):
+        # type: (Dict[str, Any], BotHandlerApi) -> str
+        """
+        If the bot is the first @mention in the message, then this function returns
+        the message with the bot's @mention removed.  Otherwise, it returns None.
+        """
+        bot_mention = r'^@(\*\*{0}\*\*)'.format(client.full_name)
+        start_with_mention = re.compile(bot_mention).match(message['content'])
+        if start_with_mention is None:
+            return None
+        query_without_mention = message['content'][len(start_with_mention.group()):]
+        return query_without_mention.lstrip()
+
+    def is_private(message, client):
+        # type: (Dict[str, Any], BotHandlerApi) -> bool
+        # bot will not reply if the sender name is the same as the bot name
+        # to prevent infinite loop
+        if message['type'] == 'private':
+            return client.full_name != message['sender_full_name']
+        return False
+
+    def handle_message(message):
+        # type: (Dict[str, Any]) -> None
+        logging.info('waiting for next message')
+
+        # is_mentioned is true if the bot is mentioned at ANY position (not necessarily
+        # the first @mention in the message).
+        is_mentioned = message['is_mentioned']
+        is_private_message = is_private(message, restricted_client)
+
+        # Strip at-mention botname from the message
+        if is_mentioned:
+            # message['content'] will be None when the bot's @-mention is not at the beginning.
+            # In that case, the message shall not be handled.
+            message['content'] = extract_query_without_mention(message=message, client=restricted_client)
+            if message['content'] is None:
+                return
+
+        if is_private_message or is_mentioned:
+            message_handler.handle_message(
+                message=message,
+                client=restricted_client,
+                state_handler=state_handler
+            )
+
+    signal.signal(signal.SIGINT, exit_gracefully)
+
+    logging.info('starting message handling...')
+    client.call_on_each_message(handle_message)