platypush/platypush/event/hook.py
Fabio Manganiello c3fa3315f5
Implemented synchronization with webhook responses.
When a client triggers a `WebhookEvent` by calling a configured webhook
over `/hook/<hook_name>`, the server will now wait for the configured
`@hook` function to complete and it will return the returned response
back to the client.

This makes webhooks much more powerful, as they can be used to proxy
HTTP calls or other services, and in general return something to the
client instead of just executing actions.
2022-08-30 23:35:19 +02:00

190 lines
6 KiB
Python

import copy
import json
import logging
import threading
from functools import wraps
from platypush.common import exec_wrapper
from platypush.config import Config
from platypush.message.event import Event
from platypush.message.request import Request
from platypush.procedure import Procedure
from platypush.utils import get_event_class_by_type, set_thread_name, is_functional_hook
logger = logging.getLogger('platypush')
def parse(msg):
"""Builds a dict given another dictionary or
a JSON UTF-8 encoded string/bytearray"""
if isinstance(msg, (bytes, bytearray)):
msg = msg.decode('utf-8')
if isinstance(msg, str):
try:
msg = json.loads(msg.strip())
except json.JSONDecodeError:
logger.warning('Invalid JSON message: {}'.format(msg))
return None
return msg
class EventCondition:
"""Event hook condition class"""
def __init__(self, type=Event.__class__, priority=None, **kwargs):
"""
Rule constructor.
Params:
type -- Class of the event to be built
kwargs -- Fields rules as a key-value (e.g. source_button=btn_id
or recognized_phrase='Your phrase')
"""
self.type = type
self.args = {}
self.parsed_args = {}
self.priority = priority
for (key, value) in kwargs.items():
# TODO So far we only allow simple value match. If value is a dict
# instead, we should allow more a sophisticated attribute matching,
# e.g. or conditions, in, and other operators.
self.args[key] = value
@classmethod
def build(cls, rule):
"""Builds a rule given either another EventRule, a dictionary or
a JSON UTF-8 encoded string/bytearray"""
if isinstance(rule, cls):
return rule
else:
rule = parse(rule)
assert isinstance(rule, dict), f'Not a valid rule: {rule}'
type = get_event_class_by_type(rule.pop('type') if 'type' in rule else 'Event')
args = {}
for (key, value) in rule.items():
args[key] = value
return cls(type=type, **args)
class EventAction(Request):
"""Event hook action class. It is a special type of runnable request
whose fields can be configured later depending on the event context"""
def __init__(self, target=None, action=None, **args):
if target is None:
target = Config.get('device_id')
args_copy = dict(copy.deepcopy(args))
super().__init__(target=target, action=action, **args_copy)
@classmethod
def build(cls, action):
action = super().parse(action)
action['origin'] = Config.get('device_id')
if 'target' not in action:
action['target'] = action['origin']
token = Config.get('token')
if token:
action['token'] = token
return super().build(action)
class EventHook:
"""Event hook class. It consists of one conditions and
one or multiple actions to be executed"""
def __init__(self, name, priority=None, condition=None, actions=None):
"""Constructor. Takes a name, a EventCondition object and an event action
procedure as input. It may also have a priority attached
as a positive number. If multiple hooks match against an event,
only the ones that have either the maximum match score or the
maximum pre-configured priority will be run."""
self.name = name
self.condition = EventCondition.build(condition or {})
self.actions = actions or []
self.priority = priority or 0
self.condition.priority = self.priority
@classmethod
def build(cls, name, hook):
"""Builds a rule given either another EventRule, a dictionary or
a JSON UTF-8 encoded string/bytearray"""
if isinstance(hook, cls):
return hook
else:
hook = parse(hook)
if is_functional_hook(hook):
actions = Procedure(name=name, requests=[hook], _async=False)
return cls(name=name, condition=hook.condition, actions=actions)
assert isinstance(hook, dict)
condition = EventCondition.build(hook['if']) if 'if' in hook else None
actions = []
priority = hook['priority'] if 'priority' in hook else None
condition.priority = priority
if 'then' in hook:
if isinstance(hook['then'], list):
actions = hook['then']
else:
actions = [hook['then']]
actions = Procedure.build(name=name + '__Hook', requests=actions, _async=False)
return cls(name=name, condition=condition, actions=actions, priority=priority)
def matches_event(self, event):
"""Returns an EventMatchResult object containing the information
about the match between the event and this hook"""
return event.matches_condition(self.condition)
def run(self, event):
"""Checks the condition of the hook against a particular event and
runs the hook actions if the condition is met"""
def _thread_func(result):
set_thread_name('Event-' + self.name)
self.actions.execute(event=event, **result.parsed_args)
result = self.matches_event(event)
if result.is_match:
logger.info('Running hook {} triggered by an event'.format(self.name))
threading.Thread(
target=_thread_func, name='Event-' + self.name, args=(result,)
).start()
def hook(event_type=Event, **condition):
def wrapper(f):
f.hook = True
f.condition = EventCondition(type=event_type, **condition)
@wraps(f)
def wrapped(event, *args, **kwargs):
from platypush.message.event.http.hook import WebhookEvent
response = exec_wrapper(f, event, *args, **kwargs)
if isinstance(event, WebhookEvent):
event.send_response(response)
return response
return wrapped
return wrapper
# vim:sw=4:ts=4:et: