Controller Interface Description

The controller offers a RESTful interface which is available over the internet and over the local network.

This interface can be used by three components:

• UE --> Controller: UE registers itself and updates its context (status) e.g. display on/off or stream on/off.
• Location Service --> Controller: The 3rd party location service can inject location information of registered UE.
• GUI <-- Controller: The GUI can use this interface to pull the current system state e.g. the context of the UEs or the status of the access points.

User Equipment

Endpoints

Endpoint	Method	Description
/api/ue	POST	Registers user equipment in the system. Creates context of UE which can later be updated by a PUT request. Returns an URL (with ID) to access the context of this UE.
/api/ue	GET	Returns a list of URLs for all currently registered UE.
/api/ue/{id}	GET	Returns the complete context (status) of the UE specified by the ID argument.
/api/ue/{id}	PUT	Updates the context of a already registered UE.
/api/ue/{id}	DELETE	Removes a UE from the system and deletes its context.

Messages

POST /api/ue and PUT /api/ue/{id}

• Request:

{
    "device_id": "device-identifier-1",
    "location_service_id": "node1",
    "position_x": 0,
    "position_y": 0,
    "display_state": 0,
    "active_application": "com.android.browser",
}

TODO: Extend this: How is ongoing data transmission (e.g. video stream) on UE described? Receiving yes/no? Bytes/s?

• Response (POST):

[
"/api/ue/9d7034c5008b11e4b714c8bcc8a0a80d"
]

• Response (PUT): No data (HTTP Status: 204)

GET /api/ue

• Response:

[
"/api/ue/9d7034c5008b11e4b714c8bcc8a0a80d",
"/api/ue/5e8e61d100fd11e4bfafc8bcc8a0a80d",
"/api/ue/57ae409e00fd11e4a3dec8bcc8a0a80d"
]

GET /api/ue/{id}

• Response:

{
    "uuid": "5e8e61d100fd11e4bfafc8bcc8a0a80d",
    "device_id": "device-identifier-1",
    "location_service_id": "node1",
    "position_x": 1234,
    "position_y": 678,
    "display_state": 0,
    "active_application": "com.android.browser",
    "assigned_accesspoint": "/api/accesspoints/57ae409e00fd11e4a3dec8bcc8a0a80d",
}

TODO: Extend this...

3rd Party Location Service

We will use a 3rd party location service in the demo. So the location of a UE is not transmitted within context updates done by the UE. To make the integration of the location service easier an additional endpoint for location updates is provided. Each update contains an identifier, which is used to map locations to UEs.

Endpoint	Method	Description
/api/location	POST	Delivers new location data. The location is mapped to the UE which has the same location identifier. If there is no matching UE in the system this call will not change anything.

Messages

POST /api/location

• Request:

{
    "location_service_id": "node1",
    "position_x": 0,
    "position_y": 0,
}

TODO: What is the correct location format of the location service?

• Response: No data (HTTP Status: 204)

Access Point Status

This interface also provides the current status of the access points which can be used for the demonstration GUI.

Endpoint	Method	Description
/api/accesspoints	GET	Returns a list (URLs) of attached access points.
/api/accesspoints/{id}	GET	Returns the current status of an access point.

Messages

GET /api/accesspoints

• Response:

[
"/api/accesspoints/9d7034c5008b11e4b714c8bcc8a0a80d",
"/api/accesspoints/5e8e61d100fd11e4bfafc8bcc8a0a80d",
"/api/accesspoints/57ae409e00fd11e4a3dec8bcc8a0a80d"
]

GET /api/accesspoints/{id}

• Response:

{
    "uuid": "5e8e61d100fd11e4bfafc8bcc8a0a80d",
    "accesspoint_id": "accesspoint-1",
    "position_x": 1234,
    "position_y": 678,
    "power_state": 0,
    "assigned_ue": [
        "/api/ue/57ae409e00fd11e4a3dec8bcc8a0a80d",
        "/api/ue/5e8e61d100fd11e4bfafc8bcc8a0a80d",
    ],
}

TODO: Which AP states do we have? On/Off? More?