bots: Create Wit.ai Bot.

Wit.ai Bot communicates with the Wit.ai API. It can be configured with
any Wit.ai token and allows for setting up a custom handler function to
handle Wit.ai responses.

tools/run-mypy

@@ -67,6 +67,8 @@ force_include = [
     "zulip_bots/zulip_bots/bots/chess/test_chess.py",
     "zulip_bots/zulip_bots/bots/xkcd/xkcd.py",
     "zulip_bots/zulip_bots/bots/xkcd/test_xkcd.py",
+    "zulip_bots/zulip_bots/bots/witai/witai.py",
+    "zulip_bots/zulip_bots/bots/witai/test_witai.py",
     "zulip_bots/zulip_bots/bots/wikipedia/wikipedia.py",
     "zulip_bots/zulip_bots/bots/wikipedia/test_wikipedia.py",
     "zulip_bots/zulip_bots/bots/yoda/yoda.py",

zulip_bots/setup.py

@@ -54,6 +54,7 @@ setuptools_info = dict(
         'lxml',  # for bots/googlesearch
         'requests',  # for bots/link_shortener
         'python-chess[engine,gaviota]',  # for bots/chess
+        'wit',  # for bots/witai
         'apiai'  # for bots/dialogflow
     ],
 )

zulip_bots/zulip_bots/bots/witai/doc.md

@@ -0,0 +1,52 @@
+# Wit.ai Bot
+
+Wit.ai Bot uses [wit.ai](https://wit.ai/) to parse natural language.
+
+## Usage
+
+ 1. Go to https://wit.ai/ and sign up.
+
+ 2. Create your Wit.ai app, or follow
+    [this quickstart guide](https://wit.ai/docs/quickstart).
+
+ 3. Create a `.conf` file containing a `token` field for your Wit.ai token,
+    and a `help_message` field for a message to display to confused users,
+    e.g.,
+
+    ```
+    [witai]
+    token = QWERTYUIOP1234
+    help_message = Ask me about my favorite food!
+    ```
+
+ 4. Create a new file named `witai_handler.py`, and inside of it, create a
+    function called `handle` with one parameter `response`. Inside of `handle`,
+    write code for whatever you want to do with the Wit.ai response. It should
+    return a `string` to respond to the user with. For example,
+
+    ```python
+    def handle(response):
+        if response['entities']['intent'][0]['value'] == 'favorite_food':
+            return 'pizza'
+        if response['entities']['intent'][0]['value'] == 'favorite_drink':
+            return 'coffee'
+    ```
+
+ 5. Add `witai_handler.py`'s location as `handler_location` in your
+    configuration file, e.g.,
+
+    ```
+    [witai]
+    token = QWERTYUIOP1234
+    handler_location = /Users/you/witai_handler_directory/witai_handler.py
+    ```
+
+ 6. Call
+
+    ```bash
+    zulip-run-bot witai \
+        --config-file <your zuliprc> \
+        --bot-config-file <the config file>
+    ```
+
+    to start the bot.

zulip_bots/zulip_bots/bots/witai/test_witai.py

@@ -0,0 +1,59 @@
+from mock import patch
+import sys
+from typing import Dict, Any, Optional
+from zulip_bots.test_lib import BotTestCase, get_bot_message_handler, StubBotHandler
+
+class TestWitaiBot(BotTestCase):
+    bot_name = 'witai'
+
+    MOCK_CONFIG_INFO = {
+        'token': '12345678',
+        'handler_location': '/Users/abcd/efgh',
+        'help_message': 'Qwertyuiop!'
+    }
+
+    MOCK_WITAI_RESPONSE = {
+        '_text': 'What is your favorite food?',
+        'entities': {
+            'intent': [{
+                'confidence': 1.0,
+                'value': 'favorite_food'
+            }]
+        }
+    }
+
+    def test_normal(self) -> None:
+        with self.mock_config_info(self.MOCK_CONFIG_INFO):
+            get_bot_message_handler(self.bot_name).initialize(StubBotHandler())
+
+            with patch('wit.Wit.message') as message:
+                message.return_value = self.MOCK_WITAI_RESPONSE
+
+                with patch('zulip_bots.bots.witai.witai.get_handle') as handler:
+                    handler.return_value = mock_handle
+
+                    self.verify_reply(
+                        'What is your favorite food?',
+                        'pizza'
+                    )
+
+    # This overrides the default one in `BotTestCase`.
+    def test_bot_responds_to_empty_message(self) -> None:
+        with self.mock_config_info(self.MOCK_CONFIG_INFO):
+            get_bot_message_handler(self.bot_name).initialize(StubBotHandler())
+
+            with patch('wit.Wit.message') as message:
+                message.return_value = self.MOCK_WITAI_RESPONSE
+
+                with patch('zulip_bots.bots.witai.witai.get_handle') as handler:
+                    handler.return_value = mock_handle
+
+                    self.verify_reply('', 'Qwertyuiop!')
+
+def mock_handle(res: Dict[str, Any]) -> Optional[str]:
+    if res['entities']['intent'][0]['value'] == 'favorite_food':
+        return 'pizza'
+    if res['entities']['intent'][0]['value'] == 'favorite_drink':
+        return 'coffee'
+
+    return None

zulip_bots/zulip_bots/bots/witai/witai.conf

@@ -0,0 +1,4 @@
+[witai]
+token = <your token>
+handler_location = <your handler location>
+help_message = <your help message>

zulip_bots/zulip_bots/bots/witai/witai.py

@@ -0,0 +1,78 @@
+# See readme.md for instructions on running this code.
+
+from typing import Dict, Any, Optional, Callable
+import wit
+import sys
+import importlib.util
+
+class WitaiHandler(object):
+    def usage(self) -> str:
+        return '''
+        Wit.ai bot uses pywit API to interact with Wit.ai. In order to use
+        Wit.ai bot, `witai.conf` must be set up. See `doc.md` for more details.
+        '''
+
+    def initialize(self, bot_handler: Any) -> None:
+        config = bot_handler.get_config_info('witai')
+
+        token = config.get('token')
+        if not token:
+            raise KeyError('No `token` was specified')
+
+        # `handler_location` should be the location of a module which contains
+        # the function `handle`. See `doc.md` for more details.
+        handler_location = config.get('handler_location')
+        if not handler_location:
+            raise KeyError('No `handler_location` was specified')
+        self.handle = get_handle(handler_location)
+
+        help_message = config.get('help_message')
+        if not help_message:
+            raise KeyError('No `help_message` was specified')
+        self.help_message = help_message
+
+        self.client = wit.Wit(token)
+
+    def handle_message(self, message: Dict[str, str], bot_handler: Any) -> None:
+        if message['content'] == '' or message['content'] == 'help':
+            bot_handler.send_reply(message, self.help_message)
+            return
+
+        try:
+            res = self.client.message(message['content'])
+            message_for_user = self.handle(res)
+
+            if message_for_user:
+                bot_handler.send_reply(message, message_for_user)
+        except wit.wit.WitError:
+            bot_handler.send_reply(message, 'Sorry, I don\'t know how to respond to that!')
+        except Exception as e:
+            bot_handler.send_reply(message, 'Sorry, there was an internal error.')
+            print(e)
+            return
+
+handler_class = WitaiHandler
+
+def get_handle(location: str) -> Callable[[Dict[str, Any]], Optional[str]]:
+    '''Returns a function to be used when generating a response from Wit.ai
+    bot. This function is the function named `handle` in the module at the
+    given `location`. For an example of a `handle` function, see `doc.md`.
+
+    For example,
+
+        handle = get_handle('/Users/someuser/witai_handler.py')  # Get the handler function.
+        res = witai_client.message(message['content'])  # Get the Wit.ai response.
+        message_res = self.handle(res)  # Handle the response and find what to show the user.
+        bot_handler.send_reply(message, message_res)  # Send it to the user.
+
+    Parameters:
+     - location: The absolute path to the module to look for `handle` in.
+    '''
+    try:
+        spec = importlib.util.spec_from_file_location('module.name', location)
+        handler = importlib.util.module_from_spec(spec)
+        spec.loader.exec_module(handler)
+        return handler.handle  # type: ignore
+    except Exception as e:
+        print(e)
+        return None