Welcome to the Google Home Developer Center, the new destination for learning how to develop smart home actions. Note: You'll continue building actions in the Actions console.

Identify and sync

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Once you have created a smart home Action, the next step is to add functionality in your fulfillment to process the smart home intents and return responses that Google Assistant recognizes.

Identify the user

Assistant makes requests to your smart home Action's fulfillment with the access token provided by your OAuth 2.0 server in the Authorization header.

POST /fulfillment HTTP/1.1
Host: smarthome.example.com
Content-Type: application/json
Authorization: Bearer ACCESS_TOKEN

Before responding to any requests, your fulfillment logic should verify that this token credential is valid and determine the associated user account. If the access token is invalid, your fulfillment should return an HTTP 401 Unauthorized error.

List devices and their capabilities

Assistant sends an action.devices.SYNC intent to your fulfillment to request the list of devices associated with the given user and their capabilities. Your fulfillment must return a unique ID for each user in the agentUserId field of the SYNC response. This ID must be an immutable value to represent the user to your cloud service. It is not recommended to provide email addresses or other attributes based on settings the user can change.

The devices field of your SYNC response contains all of the devices the user has authorized Assistant to access, the types and traits they support, and the attributes required to configure the trait's behavior for that specific device.

The SYNC intent is triggered during account linking or when a user manually resyncs their devices. If the users' list of devices, supported traits, or attribute values change, use Request Sync to trigger a new SYNC intent and report the updates to Google.

Request
{
    "requestId": "ff36a3cc-ec34-11e6-b1a0-64510650abcf",
    "inputs": [{
      "intent": "action.devices.SYNC"
    }]
}
JSON
{
  "requestId": "ff36a3cc-ec34-11e6-b1a0-64510650abcf",
  "payload": {
    "agentUserId": "1836.15267389",
    "devices": [
      {
        "id": "123",
        "type": "action.devices.types.OUTLET",
        "traits": [
          "action.devices.traits.OnOff"
        ],
        "name": {
          "defaultNames": [
            "My Outlet 1234"
          ],
          "name": "Night light",
          "nicknames": [
            "wall plug"
          ]
        },
        "willReportState": false,
        "roomHint": "kitchen",
        "deviceInfo": {
          "manufacturer": "lights-out-inc",
          "model": "hs1234",
          "hwVersion": "3.2",
          "swVersion": "11.4"
        },
        "otherDeviceIds": [
          {
            "deviceId": "local-device-id"
          }
        ],
        "customData": {
          "fooValue": 74,
          "barValue": true,
          "bazValue": "foo"
        }
      },
      {
        "id": "456",
        "type": "action.devices.types.LIGHT",
        "traits": [
          "action.devices.traits.OnOff",
          "action.devices.traits.Brightness",
          "action.devices.traits.ColorSetting"
        ],
        "name": {
          "defaultNames": [
            "lights out inc. bulb A19 color hyperglow"
          ],
          "name": "lamp1",
          "nicknames": [
            "reading lamp"
          ]
        },
        "willReportState": false,
        "roomHint": "office",
        "attributes": {
          "colorModel": "rgb",
          "colorTemperatureRange": {
            "temperatureMinK": 2000,
            "temperatureMaxK": 9000
          },
          "commandOnlyColorSetting": false
        },
        "deviceInfo": {
          "manufacturer": "lights out inc.",
          "model": "hg11",
          "hwVersion": "1.2",
          "swVersion": "5.4"
        },
        "customData": {
          "fooValue": 12,
          "barValue": false,
          "bazValue": "bar"
        }
      }
    ]
  }
}
Node.js
const {smarthome} = require('actions-on-google');
const app = smarthome();
// ...
app.onSync((body, headers) => {
  // TODO Get devices for user
  return {
    requestId: body.requestId,
    payload: {
      agentUserId: "1836.15267389",
      devices: [{
        id: "123",
        type: "action.devices.types.OUTLET",
        traits: [
          "action.devices.traits.OnOff"
        ],
        name: {
          defaultNames: ["My Outlet 1234"],
          name: "Night light",
          nicknames: ["wall plug"]
        },
        willReportState: false,
        roomHint: "kitchen",
        deviceInfo: {
          manufacturer: "lights-out-inc",
          model: "hs1234",
          hwVersion: "3.2",
          swVersion: "11.4"
        },
        otherDeviceIds: [{
          deviceId: "local-device-id"
        }],
        customData: {
          fooValue: 74,
          barValue: true,
          bazValue: "foo"
        }
      }, {
        id: "456",
        type: "action.devices.types.LIGHT",
        traits: [
          "action.devices.traits.OnOff",
          "action.devices.traits.Brightness",
          "action.devices.traits.ColorSetting"
        ],
        name: {
          defaultNames: ["lights out inc. bulb A19 color hyperglow"],
          name: "lamp1",
          nicknames: ["reading lamp"]
        },
        willReportState: false,
        roomHint: "office",
        attributes: {
          colorModel: 'rgb',
          colorTemperatureRange: {
            temperatureMinK: 2000,
            temperatureMaxK: 9000
          },
          commandOnlyColorSetting: false
        },
        deviceInfo: {
          manufacturer: "lights out inc.",
          model: "hg11",
          hwVersion: "1.2",
          swVersion: "5.4"
        },
        customData: {
          fooValue: 12,
          barValue: false,
          bazValue: "bar"
        }
      }]
    }
  };
});
Java
@NotNull
@Override
public SyncResponse onSync(@NotNull SyncRequest syncRequest, @Nullable Map<?, ?> map) {
  Payload payload = new Payload();
  payload.setAgentUserId("1836.15267389");
  payload.setDevices(
      new Device[] {
        new Device.Builder()
            .setId("123")
            .setType("action.devices.types.OUTLET")
            .addTrait("action.devices.traits.OnOff")
            .setName(
                Collections.singletonList("My Outlet 1234"),
                "Night light",
                Collections.singletonList("Wall plug"))
            .setWillReportState(true)
            .setDeviceInfo("lights-out-inc", "hs1234", "3.2", "11.4")
            .setCustomData(
                new JSONObject()
                    .put("fooValue", 74)
                    .put("barValue", true)
                    .put("bazValue", "foo"))
            .build(),
        new Device.Builder()
            .setId("456")
            .setType("action.devices.types.LIGHT")
            .addTrait("action.devices.traits.OnOff")
            .addTrait("action.devices.traits.Brightness")
            .addTrait("action.devices.traits.ColorTemperature")
            .addTrait("action.devices.traits.ColorSpectrum")
            .setName(
                Collections.singletonList("Lights Out Inc. bulb A19 color hyperglow"),
                "Lamp",
                Collections.singletonList("Reading lamp"))
            .setWillReportState(true)
            .setDeviceInfo("Lights Out Inc.", "hg11", "1.2", "5.4")
            .setCustomData(
                new JSONObject()
                    .put("fooValue", 12)
                    .put("barValue", false)
                    .put("bazValue", "bar"))
            .build(),
      });
  return new SyncResponse(syncRequest.getRequestId(), payload);
}

For more information, see the SYNC intent reference documentation.