python-thingserver/thingserver/thing.py at master · labthings/python-thingserver · GitHub

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"""High-level Thing base class implementation."""

from jsonschema import validate

from jsonschema.exceptions import ValidationError

class Thing:

"""A Web Thing."""

def __init__(self, id_, title, type_=[], description=""):

"""

Initialize the object.

id_ -- the thing's unique ID - must be a URI

title -- the thing's title

type_ -- the thing's type(s)

description -- description of the thing

"""

if not isinstance(type_, list):

type_ = [type_]

self.id = id_

self.context = "https://www.w3.org/2019/wot/td/v1"

self.type = type_

self.title = title

self.description = description

self.properties = {}

self.actions = {}

self.available_events = {}

self.events = []

self.subscribers = set()

self.href_prefix = ""

self.ui_href = None

def add_context(self, context):

if isinstance(self.context, str):

self.context = [self.context]

self.context.append(context)

def as_thing_description(self):

"""

Return the thing state as a Thing Description.

Returns the state as a dictionary.

"""

thing = {

"id": self.id,

"title": self.title,

"@context": self.context,

"properties": self.get_property_descriptions(),

"actions": self.get_action_descriptions(),

"events": {},

"links": [

{

"rel": "properties",

"href": "{}/properties".format(self.href_prefix),

{"rel": "actions", "href": "{}/actions".format(self.href_prefix),},

{"rel": "events", "href": "{}/events".format(self.href_prefix),},

}

for name, event in self.available_events.items():

thing["events"][name] = event["metadata"]

thing["events"][name]["forms"] = [

{

"op": "subscribeevent",

"href": "{}/events/{}".format(self.href_prefix, name),

"subprotocol": "longpoll"

]

if self.ui_href is not None:

thing["links"].append(

{"rel": "alternate", "mediaType": "text/html", "href": self.ui_href,}

)

if self.description:

thing["description"] = self.description

if self.type:

thing["@type"] = self.type

return thing

def get_href(self):

"""Get this thing's href."""

if self.href_prefix:

return self.href_prefix

return "/"

def get_ui_href(self):

"""Get the UI href."""

return self.ui_href

def set_href_prefix(self, prefix):

"""

Set the prefix of any hrefs associated with this thing.

prefix -- the prefix

"""

self.href_prefix = prefix

for property_ in self.properties.values():

property_.set_href_prefix(prefix)

for action_name in self.actions.keys():

for action_obj in self.actions[action_name].queue:

action_obj.set_href_prefix(prefix)

def set_ui_href(self, href):

"""

Set the href of this thing's custom UI.

href -- the href

"""

self.ui_href = href

def get_id(self):

"""

Get the ID of the thing.

Returns the ID as a string.

"""

return self.id

def get_title(self):

"""

Get the title of the thing.

Returns the title as a string.

"""

return self.title

def get_context(self):

"""

Get the type context of the thing.

Returns the context as a string.

"""

return self.context

def get_type(self):

"""

Get the type(s) of the thing.

Returns the list of types.

"""

return self.type

def get_description(self):

"""

Get the description of the thing.

Returns the description as a string.

"""

return self.description

def get_property_descriptions(self):

"""

Get the thing's properties as a dictionary.

Returns the properties as a dictionary, i.e. name -> description.

"""

return {k: v.as_property_description() for k, v in self.properties.items()}

def get_action_descriptions(self):

"""

Get the thing's available actions as a dictionary.

Returns the actions as a dictionary, i.e. name -> description.

"""

return {k: v.as_action_description() for k, v in self.actions.items()}

def get_action_object_descriptions(self, action_name=None):

"""

Get the thing's action objects as an array.

action_name -- Optional action name to get descriptions for

Returns the action descriptions.

"""

if action_name is None:

descriptions = {}

for name, action in self.actions.items():

descriptions[name] = []

for action_obj in action.queue:

descriptions[name].append(action_obj.as_action_description())

elif action_name in self.actions:

descriptions = []

for action_obj in self.actions[action_name].queue:

descriptions.append(action_obj.as_action_description())

return descriptions

def get_event_descriptions(self, event_name=None):

"""

Get the thing's events as an array.

event_name -- Optional event name to get descriptions for

Returns the event descriptions.

"""

if event_name is None:

return [e.as_event_description() for e in self.events]

else:

return [

e.as_event_description()

for e in self.events

if e.get_name() == event_name

]

def add_property(self, property_):

"""

Add a property to this thing.

property_ -- property to add

"""

property_.set_href_prefix(self.href_prefix)

self.properties[property_.name] = property_

def remove_property(self, property_):

"""

Remove a property from this thing.

property_ -- property to remove

"""

if property_.name in self.properties:

del self.properties[property_.name]

def find_property(self, property_name):

"""

Find a property by name.

property_name -- the property to find

Returns a Property object, if found, else None.

"""

return self.properties.get(property_name, None)

async def get_property(self, property_name):

"""

Get a property's value.

property_name -- the property to get the value of

Returns the properties value, if found, else None.

"""

prop = self.find_property(property_name)

if prop:

return await prop.get_value()

return None

async def get_properties(self):

"""

Get a mapping of all properties and their values.

Returns a dictionary of property_name -> value.

"""

return {

prop.get_name(): await prop.get_value() for prop in self.properties.values()

}

def has_property(self, property_name):

"""

Determine whether or not this thing has a given property.

property_name -- the property to look for

Returns a boolean, indicating whether or not the thing has the

property.

"""

return property_name in self.properties

async def set_property(self, property_name, value):

"""

Set a property value.

property_name -- name of the property to set

value -- value to set

"""

prop = self.find_property(property_name)

if not prop:

return

await prop.set_value(value)

def get_action(self, action_name, action_id):

"""

Get an action.

action_name -- name of the action

action_id -- ID of the action

Returns the requested action if found, else None.

"""

if action_name not in self.actions:

return None

for action_obj in self.actions[action_name].queue:

if action_obj.id == action_id:

return action_obj

return None

def add_event(self, event):

"""

Add a new event and notify subscribers.

event -- the event that occurred

"""

self.events.append(event)

self.event_notify(event)

def add_available_event(self, name, metadata):

"""

Add an available event.

name -- name of the event

metadata -- event metadata, i.e. type, description, etc., as a dict

"""

if metadata is None:

metadata = {}

self.available_events[name] = {

"metadata": metadata,

"subscribers": set(),

}

def init_action(self, action_name, input_=None):

"""

Initialise an action on the thing, without starting it

action_name -- name of the action

input_ -- any action inputs

Returns the action that was created.

"""

if action_name not in self.actions:

return None

action = self.actions[action_name]

if "input" in action.metadata:

try:

validate(input_, action.metadata["input"])

except ValidationError:

return None

action_obj = action.invokeaction(input_)

action_obj.set_href_prefix(self.href_prefix)

self.action_notify(action_obj)

return action_obj

def remove_action(self, action_name, action_id):

"""

Remove an existing action.

action_name -- name of the action

action_id -- ID of the action

Returns a boolean indicating the presence of the action.

"""

action_obj = self.get_action(action_name, action_id)

if action_obj is None:

return False

action_obj.cancel()

return True

def add_action(self, action):

"""

Add an available action.

action -- Action instance

"""

self.actions[action.name] = action

def add_subscriber(self, subscriber):

"""

Add a new websocket subscriber.

:param subscriber: Subscriber

"""

self.subscribers.add(subscriber)

def remove_subscriber(self, subscriber):

"""

Remove a websocket subscriber.

:param subscriber: Subscriber

"""

if subscriber in self.subscribers:

self.subscribers.remove(subscriber)

for name in self.available_events:

self.remove_event_subscriber(name, subscriber)

def add_event_subscriber(self, name, subscriber):

"""

Add a new websocket subscriber to an event.

:param name: Name of the event

:param subscriber: Subscriber

"""

if name in self.available_events:

self.available_events[name]["subscribers"].add(subscriber)

def remove_event_subscriber(self, name, subscriber):

"""

Remove a websocket subscriber from an event.

:param name: Name of the event

:param subscriber: Subscriber

"""

if (

name in self.available_events

and subscriber in self.available_events[name]["subscribers"]

self.available_events[name]["subscribers"].remove(subscriber)

def property_notify(self, property_):

"""

Notify all subscribers of a property change.

:param property_: the property that changed

"""

for subscriber in list(self.subscribers):

subscriber.update_property(property_)

def action_notify(self, action_obj):

"""

Notify all subscribers of an action status change.

:param action: The action whose status changed

"""

for subscriber in list(self.subscribers):

subscriber.update_action(action_obj)

def event_notify(self, event):

"""

Notify all subscribers of an event.

:param event: The event that occurred

"""

if event.name not in self.available_events:

return

for subscriber in self.available_events[event.name]["subscribers"]:

subscriber.update_event(event)

python-thingserver/thingserver/thing.py at master · labthings/python-thingserver · GitHub

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