# Response (/docs/settings/mqtt/topics/response) Webview Kiosk also utilises the request-response pattern for manual query of device information states.
This pattern is explained in: * [EMQX — MQTT 5: Request–Response](https://www.emqx.com/en/blog/mqtt5-request-response) * [HiveMQ — MQTT 5 Essentials Part 9: Request–Response Pattern](https://www.hivemq.com/blog/mqtt5-essentials-part9-request-response-pattern/) ## 1. Settings [#1-settings] ### 1.1. Topic Name [#11-topic-name] All [global variables](/docs/settings/mqtt/#3-global-variables) are supported, in addition to `RESPONSE_TYPE`. For example, ```js wk/${USERNAME}/${APP_INSTANCE_ID}/response/${RESPONSE_TYPE} ``` If a `responseTopic` is specified in the request, either in the payload or using MQTT V5's metadata ([3.1.3.2.7. Response Topic](https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901066)), the reply will be published to that `responseTopic` instead. **Default:** ```js wk/response/${RESPONSE_TYPE} ``` ### 1.2. Quality of Service (QoS) [#12-quality-of-service-qos] Quality of Service (QoS) ensures different message delivery guarantees in case of connection failures. **Default:** At Most Once (0) ### 1.3. Retain [#13-retain] Keep response topic messages retained for new subscribers. **Default:** false ## 2. Payloads [#2-payloads] All published events will contain the [shared payload properties](/docs/settings/mqtt/topics#2-shared-payload-properties) mentioned previously, as well as the following: | Property | Type | Description | | ------------------ | ------------------------ | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `responseType` | string | The type of response matching the request type, e.g. `get_status`. | | `requestMessageId` | string *(nullable)* | if a `messageId` was provided in the request, it will be re-used here. | | `correlationData` | string *(nullable)* | if provided in the request, either in the payload or using MQTT V5's metadata ([3.1.3.2.7. Correlation Data](https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901067)), it will be present here in addition to the message's metadata. | ### 2.1. Get Status [#21-get-status] This response is published when a `get_status` request is received. Example Payload: ```json { "responseType": "get_status", "messageId": "e3d50b37-febf-4289-86ff-bf2f5506fafc", "username": "medium-phone-api-35", "appInstanceId": "42188f0c-6784-4a52-95b6-8569f0f4d2f1", "requestMessageId": null, "correlationData": null, "data": { "currentUrl": "https://webviewkiosk.nktnet.uk", "isLocked": false, "lockStateType": "NONE", "lastInteractionTime": 1764695317211, "batteryPercentage": 62, "appBrightnessPercentage": -1, "systemBrightness": 255, "isDeviceInteractive": true } } ``` ### 2.2. Get Settings [#22-get-settings] This response is published when a `get_settings` request is received. The returned settings will depend on what was included in the request payload. Example Payload: ```jsonc { "responseType": "get_settings", "messageId": "887eb103-43c8-4306-b9cc-97f1e8499fe1", "username": "medium-phone-api-35", "appInstanceId": "42188f0c-6784-4a52-95b6-8569f0f4d2f1", "requestMessageId": null, "correlationData": null, "data": { "settings": { // Response settings depends on the request payload "appearance.theme": "SYSTEM", "device.rotation": "AUTO" } } } ``` ### 2.3. Get System Info [#23-get-system-info] This response is published when a `get_system_info` request is received. ```json { "responseType": "get_system_info", "messageId": "154ec3ff-ff5a-49e6-9fa0-f6311e6893b8", "username": "medium-phone-api-35", "appInstanceId": "42188f0c-6784-4a52-95b6-8569f0f4d2f1", "requestMessageId": null, "correlationData": null, "data": { "app": { "name": "Webview Kiosk", "packageName": "uk.nktnet.webviewkiosk", "versionName": "0.25.0.12-mqtt-beta", "versionCode": 98, "minSdk": 21, "targetSdk": 36, "isDebug": true, "installer": null, "isDeviceOwner": false, "isLockTaskPermitted": true, "dhizukuPermissionGranted": true, "instanceId": "42188f0c-6784-4a52-95b6-8569f0f4d2f1", "sourceCodeUrl": "https://github.com/nktnet1/webview-kiosk" }, "device": { "releaseVersion": "15", "sdkVersion": 35, "incrementalVersion": "12592187", "webViewVersion": "141.0.7390.122", "screenWidth": 1080, "screenHeight": 2400, "screenDensity": 2.625, "isManagedProfile": false, "timeZone": "Australia/Sydney", "locale": "en_US", "totalMemory": 2070986752, "totalStorage": 6228115456, "manufacturer": "Google", "model": "sdk_gphone64_arm64", "brand": "google", "device": "emu64a", "product": "sdk_gphone64_arm64", "hardware": "ranchu", "board": "goldfish_arm64", "bootloader": "unknown", "securityPatch": "2024-09-05", "supportedAbis": [ "arm64-v8a" ], "supported32BitAbis": [], "supported64BitAbis": [ "arm64-v8a" ], "buildFingerprint": "google/sdk_gphone64_arm64/emu64a:15/AE3A.240806.036/12592187:user/release-keys" } } } ``` ### 2.4. Get Launchable Packages [#24-get-launchable-packages] This response is published when a `get_launchable_packages` request is received. Example Payload: ```json { "responseType": "get_launchable_packages", "messageId": "69569438-c6c7-488f-bce4-f9b348e3baad", "username": "medium-phone-api-35", "appInstanceId": "42188f0c-6784-4a52-95b6-8569f0f4d2f1", "requestMessageId": null, "correlationData": null, "data": { "packages": [ "com.afwsamples.testdpc", "com.android.vending", "com.bintianqi.owndroid", "com.google.android.calendar", "com.google.android.deskclock", "com.looker.droidify" "com.rosan.dhizuku", "com.termux", "moe.shizuku.privileged.api" "uk.nktnet.webviewkiosk" ] } } ``` ### 2.5. Get Lock Task Packages [#25-get-lock-task-packages] This response is published when a `get_lock_task_packages` request is received. Example Payload: ```json { "responseType": "get_lock_task_packages", "messageId": "aa92ece1-4daf-4a44-83ad-cbfc5317f8c0", "username": "medium-phone-api-35", "appInstanceId": "42188f0c-6784-4a52-95b6-8569f0f4d2f1", "requestMessageId": null, "correlationData": null, "data": { "packages": [ "com.google.android.calendar", "com.google.android.deskclock", "uk.nktnet.webviewkiosk" ] } } ``` ### 2.6. Error [#26-error] This response is published whenever an error occurs with processing a request. For example, the `requestType` could be invalid. Example Payload: ```json { "responseType": "error", "messageId": "058a8f44-d34a-43b6-a7e7-8f5537cea62f", "username": "medium-phone-api-35", "appInstanceId": "42188f0c-6784-4a52-95b6-8569f0f4d2f1", "requestMessageId": null, "correlationData": null, "payloadStr": "{\n \"requestType\": \"invalid\"\n}", "errorMessage": "Unexpected JSON token at offset 0: Serializer for subclass 'invalid' is not found in the polymorphic scope of 'MqttRequestMessage' at path: $\nCheck if class with serial name 'invalid' exists and serializer is registered in a corresponding SerializersModule.\nTo be registered automatically, class 'invalid' has to be '@Serializable', and the base class 'MqttRequestMessage' has to be sealed and '@Serializable'.\nJSON input: {\n \"requestType\": \"invalid\"\n}" } ```