mirror of
https://github.com/vanitasvitae/Smack.git
synced 2024-11-24 13:02:06 +01:00
116 lines
4.7 KiB
Markdown
116 lines
4.7 KiB
Markdown
Internet of Things (XEP-0323, -0324, -0325, -0347)
|
|
==================================================
|
|
|
|
The Internet of Things (IoT) XEPs are an experimental open standard how XMPP can be used for IoT. They currently consists of
|
|
- XEP-0323 Sensor Data
|
|
- XEP-0324 Provisioning
|
|
- XEP-0325 Control
|
|
- XEP-0326 Concentrators
|
|
- XEP-0347 Discovery
|
|
|
|
Smack only supports a subset of the functionality described by the XEPs!
|
|
|
|
Thing Builder
|
|
-------------
|
|
|
|
The `org.jivesoftware.smackx.iot.Thing` class acts as basic entity representing a single "Thing" which can used to retrieve data from or to send control commands to. `Things` are constructed using a builder API.
|
|
|
|
|
|
Reading data from things
|
|
------------------------
|
|
|
|
For example, we can build a Thing which provides the current temperature with
|
|
|
|
```java
|
|
Thing dataThing = Thing.builder().setKey(key).setSerialNumber(sn).setMomentaryReadOutRequestHandler(new ThingMomentaryReadOutRequest() {
|
|
@Override
|
|
public void momentaryReadOutRequest(ThingMomentaryReadOutResult callback) {
|
|
int temp = getCurrentTemperature();
|
|
IoTDataField.IntField field = new IntField("temperature", temp);
|
|
callback.momentaryReadOut(Collections.singletonList(field));
|
|
}
|
|
}).build();
|
|
```
|
|
|
|
While not strictly required, most things are identified via a key and serial number. We also build the thing with a "momentary read out request handler" which when triggered, retrieved the current temperature and reports it back to the requestor.
|
|
|
|
After the `Thing` is build, it needs to be made available so that other entities within the federated XMPP network can use it. Right now, we only intall the Thing in the `IoTDataManager`, which means the thing will act on read out requests but not be managed by a provisioning server.
|
|
|
|
```java
|
|
IoTDataManager iotDataManager = IoTDataManager.getInstanceFor(connection);
|
|
iotDataManager.installThing(thing);
|
|
```
|
|
|
|
The data can be read out also by using the `IoTDataManager`:
|
|
|
|
```java
|
|
FullJid jid = …
|
|
List<IoTFieldsExtension> values = iotDataManager.requestMomentaryValuesReadOut(jid);
|
|
```
|
|
|
|
Now you have to unwrap the `IoTDataField` instances from the `IoTFieldsExtension`. Note that Smack currently only supports a subset of the specified data types.
|
|
|
|
Controlling a thing
|
|
-------------------
|
|
|
|
Things can also be controlled, e.g. to turn on a light. Let's create thing which can be used to turn the light on and off.
|
|
|
|
```java
|
|
Thing controlThing = Thing.builder().setKey(key).setSerialNumber(sn).setControlRequestHandler(new ThingControlRequest() {
|
|
@Override
|
|
public void processRequest(Jid from, Collection<SetData> setData) throws XMPPErrorException {
|
|
for (final SetData data : setData) {
|
|
if (!data.getName().equals("light")) continue;
|
|
if (!(data instanceof SetBoolData)) continue;
|
|
SetBoolData boolData = (SetBoolData) data;
|
|
setLight(boolData.getBooleanValue());
|
|
}
|
|
}
|
|
}).build();
|
|
```
|
|
|
|
No we have to install this thing into the `IoTControlManager`:
|
|
|
|
```java
|
|
IoTControlManager iotControlManager = IoTControlManager.getInstanceFor(connection);
|
|
iotControlManager.installThing(thing);
|
|
```
|
|
|
|
The `IoTControlManager` can also be used to control a thing:
|
|
|
|
```java
|
|
FullJid jid = …
|
|
SetData setData = new SetBoolData("light", true);
|
|
iotControlManager.setUsingIq(jid, setData);
|
|
```
|
|
|
|
Smack currently only supports a subset of the possible data types for set data.
|
|
|
|
Discovery
|
|
---------
|
|
|
|
You may wondered how a full JIDs of things can be determined. One approach is using the discovery mechanisms specified in XEP-0347. Smack provides the `IoTDiscoveryManager` as API for this.
|
|
|
|
For example, instead of just installing the previous things in the `IoTDataManager` and/or `IoTControlManager`, we could also use the `IoTDiscoveryManger` to register the thing with a registry. Doing thing also installs the thing in the `IoTDataManager` and the `IoTControlManager`.
|
|
|
|
```java
|
|
IoTDiscoveryManager iotDiscoveryManager = IoTDiscoveryManager.getInstanceFor(connection);
|
|
iotDiscovyerManager.registerThing(thing);
|
|
```
|
|
|
|
The registry will now make the thing known to a broader audience, and available for a potential owner.
|
|
|
|
The `IoTDiscoveryManager` can also be used to claim, disown, remove and unregister a thing.
|
|
|
|
Provisioning
|
|
------------
|
|
|
|
Things can usually only be used by other things if they are friends. Since a thing normally can't decide on its own if an incoming friendship request should be granted or not, we can delegate this decission to a provisioning service. Smack provides the `IoTProvisinoManager` to deal with friendship and provisioning.
|
|
|
|
For example, if you want to befriend another thing:
|
|
|
|
```java
|
|
BareJid jid = …
|
|
IoTProvisioningManager iotProvisioningManager = IoTProvisioningManager.getInstanceFor(connection);
|
|
iotProvisioningManager.sendFriendshipRequest(jid);
|
|
```
|