dart_wot is an implementation of the Web of Things Scripting API modelled after the WoT reference implementation node-wot. At the moment, it supports interacting with Things using the Constrained Application Protocol (CoAP), the Hypertext Transfer Protocol (HTTP), and the MQTT protocol.
You can consume Thing Descriptions and interact with a Thing based on its exposed Properties, Actions, and Events. Discovery support is currently limited to the "direct" method (i.e. fetching a TD using a single URL). Exposing Things is not yet supported but will be added in future versions.
Using the Protocol Interfaces in the core package, you can add support for
additional protocols in your own application or library. The main requirement
for this to work is the existence of a URI scheme for the given protocol.
To get started, you first need to install the package by adding it to your
pubspec.yaml file.
You can use dart pub add dart_wot (for a Dart project) or
flutter pub add dart_wot (for a Flutter project) to do so.
You can then use the package in your project by adding
import 'package:dart_wot/dart_wot.dart' to your source files.
Below you can find a basic example for incrementing and reading the value of a counter Thing, which is part of the Thingweb Online Things.
In the example, we first create a WoT runtime using a Servient with CoAP and
HTTP support.
With the runtime, we then retrieve a TD (using the requestThingDescription()
method) and consume it (using the consume() method), creating a
ConsumedThing object,
Afterward, the actual interactions with the counter are performed by calling the
invokeAction() and readProperty() methods on the ConsumedThing.
import "package:dart_wot/binding_coap.dart";
import "package:dart_wot/binding_http.dart";
import "package:dart_wot/core.dart";
Future<void> main(List<String> args) async {
final servient = Servient.create(
clientFactories: [
CoapClientFactory(),
HttpClientFactory(),
],
);
final wot = await servient.start();
final url = Uri.parse("coap://plugfest.thingweb.io/counter");
print("Requesting TD from $url ...");
final thingDescription = await wot.requestThingDescription(url);
final consumedThing = await wot.consume(thingDescription);
print(
"Successfully retrieved and consumed TD with title "
'"${thingDescription.title}"!',
);
print(consumedThing.thingDescription.events);
final subscription = await consumedThing.subscribeEvent("change", print);
print("Incrementing counter ...");
await consumedThing.invokeAction("increment");
final status = await consumedThing.readProperty("count");
final value = await status.value();
print("New counter value: $value");
await subscription.stop();
}More complex examples can be found in the example directory.
dart_wot is licensed under the 3-Clause BSD License.
See the LICENSE file for more information.
SPDX-License-Identifier: BSD-3-Clause
dart_wot was inspired by Eclipse Thingweb
node-wot, a W3C Web of Things
implementation for the Node.js ecosystem.
Please refer to our contribution guidelines for more details.
This project is currently maintained by the following developers:
| Name | Email Address | GitHub Username |
|---|---|---|
| Jan Romann | jan.romann@uni-bremen.de | JKRhb |