Widgets Development Guide Before 3.0

• Introduction
• Creating new widget definition
  • Widget Editor overview
    • Widget Editor Toolbar
    • Resources/HTML/CSS section
    • JavaScript section
    • Settings schema section
    • Widget preview section
  • Basic widget API
    • Subscription object
    • Timewindow functions
    • Control API
    • Actions API
    • State Controller
    • Type parameters object
    • Action sources object
  • Creating simple widgets
    • Latest Values widget
    • Time-Series widget
    • RPC (Control) widget
    • Alarm widget
    • Static widget
• Integrating existing code to create widget definition
  • Using external JavaScript library
  • Using existing JavaScript code
• Widget code debugging tips
• Next steps

Introduction

This is a widget development guide for the ThingsBoard version before the ThingsBoard 3.0 version. In case if you are using the ThingsBoard 3.0+ version, you can refer to the next link for the Widget Development ThingsBoard 3.0+ version guide.

ThingsBoard widgets are additional UI modules that can be easily integrated into any IoT Dashboards and provide end-user functions such as data visualization, remote device control, alarms management and displaying static custom html content. According to the provided features each widget definition represents specific Widget Type.

Creating new widget definition

In order to create a new widget definition navigate “Widget Library”. Then open existing “Widgets Bundle” or create a new one. In the “Widgets Bundle” view click on the big “+” button in the bottom-right part of the screen and then click on the “Create new widget type” button.

Select widget type window should popup and you will be prompted to select corresponding widget type that you are going to develop.

After that the “Widget Editor” page will be opened pre-populated with the starter widget template according to the previously selected widget type.

Widget Editor overview

Widget Editor view represents mini IDE designed to develop custom widget definitions. It consists of top toolbar and four main sections:

• Resources/HTML/CSS
• JavaScript
• Settings schema
• Widget preview

Widget Editor Toolbar

Widget Editor Toolbar consists of the following items:

• Widget Title field - used to specify title of the widget definition
• Widget Type selector - used to specify type of the widget definition
• Run button - used to run widget code and view result in Widget preview section
• Undo button - reverts all editor sections to latest saved state
• Save button - saves widget definition
• Save as button - allows to save a new copy of widget definition by specifying new widget type name and target Widgets Bundle

Resources/HTML/CSS section

This section consists of three tabs. The first Resources tab is used to specify external JavaScript/CSS resources used by the widget.

Second HTML tab contains widget html code (Note: some widgets create html content dynamically and initial html content can be empty).

Third CSS tab contains widget specific CSS style definitions.

JavaScript section

This section contains all widget related JavaScript code according to the Widget API.

Settings schema section

This section consists of two tabs. The first Settings schema tab is used to specify json schema of widget settings in order to auto-generate UI form using react-schema-form builder. This generated UI form is displayed in the Advanced tab of widget settings. Settings Object serialized by this schema is used to store specific widget settings and accessible from widget JavaScript code.

Second Data key settings schema tab is used to specify json schema of particular data key settings in order to auto-generate UI form using react-schema-form builder. This generated UI form is displayed in Advanced tab of the Data key configuration dialog. Settings Object serialized by this schema is used to store specific settings for each data key of the datasource defined in the widget. These settings are accessible from widget JavaScript code.

Widget preview section

This section is used to preview and test widget definition. It is presented as mini dashboard containing one widget instantiated from the current widget definition. It has mostly all functionality provided by usual ThingsBoard dashboard but has some limitations. For example, only “Function” can be selected as datasource type in widget datasources section for debug purposes.

Basic widget API

All widget related code is located in the JavaScript section. The built-in variable self that is a reference to the widget instance is also available. Each widget function should be defined as a property of the self variable. self variable has property ctx - reference to widget context that has all necessary API and data used by widget instance. Below is brief description of widget context properties:

In order to implement new widget the following JavaScript functions should be defined (Note: each function is optional and can be implemented according to the widget specific/behaviour):

Subscription object

Widget subscription object contains all subscription information including current data according to the widget type. Depending on widget type subscription object provides different data structures. For Latest values and Time-series widget types it provides the following properties:

• datasources - array of datasources used by this subscription and has the following structure:

    datasources = [
        {  // datasource
           type: 'entity',// type of the datasource. Can be "function" or "entity"
           name: 'name', // name of the datasource (in case of "entity" usually Entity name)
           aliasName: 'aliasName', // name of the alias used to resolve this particular datasource Entity
           entityName: 'entityName', // name of the Entity used as datasource
           entityType: 'DEVICE', // datasource Entity type (for ex. "DEVICE", "ASSET", "TENANT", etc.)
           entityId: '943b8cd0-576a-11e7-824c-0b1cb331ec92', // entity identificator presented as string uuid. 
           dataKeys: [ // array of keys (attributes or timeseries) of the entity used to fetch data 
               { // dataKey
                    name: 'name', // the name of the particular entity attribute/timeseries 
                    type: 'timeseries', // type of the dataKey. Can be "timeseries", "attribute" or "function" 
                    label: 'Sin', // label of the dataKey. Used as display value (for ex. in the widget legend section) 
                    color: '#ffffff', // color of the key. Can be used by widget to set color of the key data (for ex. lines in line chart or segments in the pie chart).  
                    funcBody: "", // only applicable for datasource with type "function" and "function" key type. Defines body of the function to generate simulated data.
                    settings: {} // dataKey specific settings with structure according to the defined Data key settings json schema. See "Settings schema section".
               },
               //...
           ]
        },
        //...
    ]

• data - array of latest data received in scope of this subscription and has the following structure:

    data = [
        {
            datasource: {}, // datasource object of this data. See datasource structure above.
            dataKey: {}, // dataKey for which the data is held. See dataKey structure above.
            data: [ // array of data points
                [   // data point
                    1498150092317, // unix timestamp of datapoint in milliseconds
                    1, // value, can be either string, numeric or boolean  
                ],
                //...
            ]  
        },
        //...
    ]     

For Alarm widget type it provides the following properties:

• alarmSource - information about entity for which alarms are fetched and has the following structure:

    alarmSource = {
         type: 'entity',// type of the alarm source. Can be "function" or "entity"
         name: 'name', // name of the alarm source (in case of "entity" usually Entity name)
         aliasName: 'aliasName', // name of the alias used to resolve this particular alarm source Entity
         entityName: 'entityName', // name of the Entity used as alarm source
         entityType: 'DEVICE', // alarm source Entity type (for ex. "DEVICE", "ASSET", "TENANT", etc.)
         entityId: '943b8cd0-576a-11e7-824c-0b1cb331ec92', // entity identificator presented as string uuid. 
         dataKeys: [ // array of keys indicating alarm fields used to display alarms data 
            { // dataKey
                 name: 'name', // the name of the particular alarm field 
                 type: 'alarm', // type of the dataKey. Only "alarm" in this case. 
                 label: 'Severity', // label of the dataKey. Used as display value (for ex. as a column title in the Alarms table) 
                 color: '#ffffff', // color of the key. Can be used by widget to set color of the key data.  
                 settings: {} // dataKey specific settings with structure according to the defined Data key settings json schema. See "Settings schema section".
            },
            //...
          ] 
    }

• alarms - array of alarms received in scope of this subscription and has the following structure:

    alarms = [
        { // alarm
            id: { // alarm id 
                entityType: "ALARM", 
                id: "943b8cd0-576a-11e7-824c-0b1cb331ec92"
            },
            createdTime: 1498150092317, // Alarm created time (unix timestamp)
            startTs: 1498150092316, // Alarm started time (unix timestamp)
            endTs: 1498563899065, // Alarm end time (unix timestamp)
            ackTs: 0, // Time of alarm aknowledgment (unix timestamp)
            clearTs: 0, // Time of alarm clear (unix timestamp)
            originator: { // Originator - id of entity produced this alarm 
                entityType: "ASSET", 
                id: "ceb16a30-4142-11e7-8b30-d5d66714ea5a"
            },
            originatorName: "Originator Name", // Name of originator entity
            type: "Temperature", // Type of the alarm            
            severity: "CRITICAL", // Severity of the alarm ("CRITICAL", "MAJOR", "MINOR", "WARNING", "INDETERMINATE") 
            status: "ACTIVE_UNACK", // Status of the alarm 
                                    // ("ACTIVE_UNACK" - active unacknowledged, 
                                    // "ACTIVE_ACK" - active acknowledged, 
                                    // "CLEARED_UNACK" - cleared unacknowledged, 
                                    // "CLEARED_ACK" - cleared acknowledged)
            details: {} // Alarm details object derived from alarm details json.
        }
    ]               

For other widget types like RPC or Static subscription object is optional and does not contain necessary information.

Timewindow functions

Object with timewindow functions used to manage widget data time frame. Can by used by Time-series or Alarm widgets.

Control API

Object that provides API functions for RPC (Control) widgets.

Actions API

Set of API functions to work with user defined actions.

State Controller

Reference to Dashboard state controller providing API to manage current dashboard state.

Type parameters object

Object describing widget datasource parameters. It has the following properties:

    return {
        maxDatasources: -1, // Maximum allowed datasources for this widget, -1 - unlimited
        maxDataKeys: -1 //Maximum allowed data keys for this widget, -1 - unlimited
    }

Action sources object

Map describing available widget action sources to which user actions can be assigned. It has the following structure:

   return {
        'headerButton': { // Action source Id (unique action source identificator)
           name: 'Header button', // Display name of action source, used in widget settings ('Actions' tab).
           multiple: true // Boolean property indicating if this action source supports multiple action definitions (for ex. multiple buttons in one cell, or only one action can by assigned on table row click.)
        }
    };   

Creating simple widgets

Below is the set of simple tutorials how to create minimal widgets of each type. In order to minimize the amount of code, the Angular framework will be used, on which ThingsBoard UI is actually based. By the way, you can always use pure JavaScript or jQuery API in your widget code.

Latest Values widget

In the Widgets Bundle view click on the big “+” button in the bottom-right part of the screen and then click on the “Create new widget type” button. Click on the Latest Values button in the Select widget type popup. The Widget Editor will be opened pre-populated with the content of the default Latest Values template widget.

• Clear content of the CSS tab of “Resources” section.
• Put the following HTML code inside the HTML tab of “Resources” section:

  <div flex layout="column" style="height: 100%;" layout-align="center stretch">
      <div>My first latest values widget.</div>
      <div flex layout="row" ng-repeat="dataKeyData in data" layout-align="space-around center">
          <div>{{dataKeyData.dataKey.label}}:</div>
          <div>{{dataKeyData.data[0][0] | date : 'yyyy-MM-dd HH:mm:ss'}}</div>
          <div>{{dataKeyData.data[0][1]}}</div>
      </div>
  </div>

• Put the following JavaScript code inside the “JavaScript” section:

    self.onInit = function() {
        
        self.ctx.$scope.data = self.ctx.defaultSubscription.data;
    
    }

• Click on the Run button in the Widget Editor Toolbar in order to see the result in Widget preview section.

In this example the data property of subscription is assigned to the $scope and become accessible within HTML template. Inside the HTML a special ng-repeat angular directive is used in order to iterate over available dataKeys datapoints and render corresponding latest values with their timestamps.

Time-Series widget

In the Widgets Bundle view click on the big “+” button in the bottom-right part of the screen and then click on the “Create new widget type” button. Click on the Time-Series button in the Select widget type popup. The Widget Editor will be opened pre-populated with the content of default Time-Series template widget.

• Clear content of the CSS tab of “Resources” section.
• Put the following HTML code inside the HTML tab of “Resources” section:

  <div flex layout="column" style="height: 100%;">
      <div>My first Time-Series widget.</div>
      <md-tabs md-border-bottom>
          <md-tab ng-repeat="datasource in datasources track by $index" label="{{datasource.name}}">
              <table style="width: 100%;">
                  <thead>
                      <tr>
                          <th>Timestamp</th>
                          <th ng-repeat="dataKeyData in datasourceData[$index]">{{dataKeyData.dataKey.label}}</th>
                      <tr>          
                  </thead>
                  <tbody>
                      <tr ng-repeat="data in datasourceData[$index][0].data track by $index">
                          <td>{{data[0] | date : 'yyyy-MM-dd HH:mm:ss'}}</td>
                          <td ng-repeat="dataKeyData in datasourceData[$parent.$index]">{{dataKeyData.data[$parent.$index][1]}}</td>
                      </tr>      
                  </tbody>          
              </table>          
          </md-tab>       
      </md-tabs>      
  </div>

• Put the following JavaScript code inside the “JavaScript” section:

self.onInit = function() {
    self.ctx.$scope.datasources = self.ctx.defaultSubscription.datasources;
    self.ctx.$scope.data = self.ctx.defaultSubscription.data;
    
    self.ctx.$scope.datasourceData = [];
    
    var currentDatasource = null;
    var currentDatasourceIndex = -1;
    
    for (var i=0;i<self.ctx.$scope.data.length;i++) {
        var dataKeyData = self.ctx.$scope.data[i];
        if (dataKeyData.datasource != currentDatasource) {
            currentDatasource = dataKeyData.datasource
            currentDatasourceIndex++;
            self.ctx.$scope.datasourceData[currentDatasourceIndex] = [];
            
        } 
        self.ctx.$scope.datasourceData[currentDatasourceIndex].push(dataKeyData);
    }

}

self.onDataUpdated = function() {
    self.ctx.$scope.$digest();
}

• Click on the Run button in the Widget Editor Toolbar in order to see the result in Widget preview section.

In this example the datasources and data property of subscription is assigned to the $scope and become accessible within HTML template. The datasourceData scope property is introduced to map datasource specific dataKeys data by datasource index for flexible access within HTML template. Inside the HTML a special ng-repeat angular directive is used in order to iterate over available datasources and render corresponding tabs. Inside each tab the table is rendered using dataKeys data obtained from datasourceData scope property accessed by datasource index. Each table renders columns by iterating over all dataKeyData objects and renders all available datapoints by iterating over data array of each dataKeyData to render timestamps and values. Note that in this code onDataUpdated function is implemented with a call to angular $digest function necessary to perform new rendering cycle when new data is received.

RPC (Control) widget

In the Widgets Bundle view click on the big “+” button in the bottom-right part of the screen and then click on the “Create new widget type” button. Click on the Control Widget button in the Select widget type popup. The Widget Editor will be opened pre-populated with the content of default Control template widget.

• Clear content of the CSS tab of “Resources” section.
• Put the following HTML code inside the HTML tab of “Resources” section:

  <form name="rpcForm" ng-submit="sendCommand()">
    <md-content class="md-padding" layout="column">
        <md-input-container>
          <label>RPC method</label>  
          <input required name="rpcMethod" ng-model="rpcMethod"/>
          <div ng-messages="rpcForm.rpcMethod.$error">
            <div ng-message="required">RPC method name is required.</div>
          </div>
        </md-input-container>    
        <md-input-container>
          <label>RPC params</label>  
          <input required name="rpcParams" ng-model="rpcParams"/>
          <div ng-messages="rpcForm.rpcParams.$error">
            <div ng-message="required">RPC params is required.</div>
          </div>
        </md-input-container>    
        <md-button ng-disabled="rpcForm.$invalid || !rpcForm.$dirty" type="submit"
                   class="md-raised md-primary">
            Send RPC command
        </md-button>
        <div>
           <label>RPC command response</label>
           <div style="width: 100%; height: 100px; border: solid 2px gray" ng-bind-html="rpcCommandResponse">
           </div>       
        </div>
    </md-content>
  </form>

• Put the following JSON content inside the “Settings schema” tab of Settings schema section:

{
    "schema": {
        "type": "object",
        "title": "Settings",
        "properties": {
            "oneWayElseTwoWay": {
                "title": "Is One Way Command",
                "type": "boolean",
                "default": true
            },
            "requestTimeout": {
                "title": "RPC request timeout",
                "type": "number",
                "default": 500
            }
        },
        "required": []
    },
    "form": [
        "oneWayElseTwoWay",
        "requestTimeout"
    ]
} 

• Put the following JavaScript code inside the “JavaScript” section:

self.onInit = function() {
    
    self.ctx.$scope.sendCommand = function() {
        var rpcMethod = self.ctx.$scope.rpcMethod;
        var rpcParams = self.ctx.$scope.rpcParams;
        var timeout = self.ctx.settings.requestTimeout;
        var oneWayElseTwoWay = self.ctx.settings.oneWayElseTwoWay ? true : false;
        
        var commandPromise;
        if (oneWayElseTwoWay) {
            commandPromise = self.ctx.controlApi.sendOneWayCommand(rpcMethod, rpcParams, timeout);
        } else {
            commandPromise = self.ctx.controlApi.sendTwoWayCommand(rpcMethod, rpcParams, timeout);
        }
        commandPromise.then(
            function success(response) {
                if (oneWayElseTwoWay) {
                    self.ctx.$scope.rpcCommandResponse = "Command was successfully received by device.<br/> No response body because of one way command mode.";
                } else {
                    self.ctx.$scope.rpcCommandResponse = "Response from device:<br/>";                    
                    self.ctx.$scope.rpcCommandResponse += angular.toJson(response);
                }
            },
            function fail(rejection) {
                self.ctx.$scope.rpcCommandResponse = "Failed to send command to the device:<br/>"
                self.ctx.$scope.rpcCommandResponse += "Status: " + rejection.status + "<br/>";
                self.ctx.$scope.rpcCommandResponse += "Status text: '" + rejection.statusText + "'";
            }
            
        );
    }
    
}

• Fill Widget title field with widget type name, for ex. “My first control widget”.
• Click on the Run button in the Widget Editor Toolbar in order to see the result in Widget preview section.
• Now click dashboard edit button in the preview section and change the size of the resulting widget. Then click dashboard apply button. The final widget should look like on the image below.

• Click on the Save button in the Widget Editor Toolbar in order to save widget type.

To test how this widget performs RPC commands we will need to place this widget to some dashboard and bind to some device working with RPC commands. To do this perform the following steps:

• Login as Tenant administrator.
• Navigate to Devices and create new device with some name, for ex. “My RPC Device”.
• Open device details and click “Copy Access Token” button in order to copy device access token to clipboard.
• Download mqtt-js-rpc-from-server.sh and mqtt-js-rpc-from-server.js. Place these files to some folder. Edit mqtt-js-rpc-from-server.sh - replace $ACCESS_TOKEN with your device access token from the clipboard.
• Run mqtt-js-rpc-from-server.sh script. You should see a “connected” message in the console if all went ok.
• Navigate to Dashboards and create a new dashboard with some name, for ex. “My first control dashboard”. Open this dashboard.
• Click dashboard “edit” button. In the dashboard edit mode click on the “Entity aliases” button located on the dashboard toolbar.

• Inside Entity aliases popup click “Add alias”.
• Fill “Alias name” field, for ex. “My RPC Device Alias”.
• Select “Entity list” in “Filter type” field.
• Choose “Device” in “Type” field.
• Select your device in “Entity list” field. In this example “My RPC Device”.

• Click “Add” and then “Save” in Entity aliases.
• Click dashboard “+” button then click “Create new widget” button.

• Then select Widget Bundle where your RPC widget was saved. Select “Control widget” tab.
• Click on your widget. In this example “My first control widget”.
• In Add Widget popup select your device alias in Target device section. In this example “My RPC Device Alias”.
• Click Add. Your Control widget will appear in the dashboard. Click dashboard Apply changes button in order to save dashboard and leave editing mode.
• Fill RPC method field with RPC method name. For ex. “TestMethod”.
• Fill RPC params field with RPC params. For ex. “{ param1: “value1” }”.
• Click Send RPC command button. You should see the following response in the widget.

The following output should be printed in the device console:

  request.topic: v1/devices/me/rpc/request/0
  request.body: {"method":"TestMethod","params":"{ param1: \"value1\" }"}

In order to test “Two way” RPC command mode, we need to change the corresponding widget settings property. To do this perform the following steps:

• Click dashboard “edit” button. In dashboard edit mode click Edit widget button located in the header of Control widget.
• In the widget details view select “Advanced” tab and uncheck “Is One Way Command” checkbox.

• Click Apply changes button in the widget details header. Close details and click dashboard Apply changes button.
• Fill widget fields with RPC method name and params like in previous steps. Click Send RPC command button. You should see the following response in the widget.

• stop mqtt-js-rpc-from-server.sh script. Click Send RPC command button. You should see the following response in the widget.

In this example controlApi is used to send RPC commands. Additionally, custom widget settings were introduced in order to configure RPC command mode and RPC request timeout. The response from the device is handled by commandPromise that has success and failed callbacks with corresponding response or rejection objects containing information about request execution result.

Alarm widget

In the Widgets Bundle view click on the big “+” button in the bottom-right part of the screen and then click on the “Create new widget type” button. Click on the Alarm Widget button in the Select widget type popup. The Widget Editor will be opened pre-populated with the content of the default Alarm template widget.

• Put the following HTML code inside the HTML tab of “Resources” section:

  <div flex layout="column" style="height: 100%;">
      <div>My first Alarm widget.</div>
      <table style="width: 100%;">
          <thead>
              <tr>
                  <th ng-repeat="dataKey in alarmSource.dataKeys">{{dataKey.label}}</th> 
              <tr>          
          </thead>
          <tbody>
              <tr ng-repeat="alarm in alarms">
                  <td ng-repeat="dataKey in alarmSource.dataKeys" 
                      ng-style="getAlarmCellStyle(alarm, dataKey)">
                      {{getAlarmValue(alarm, dataKey)}}
                  </td>
              </tr>      
          </tbody>          
      </table>          
  </div>

• Put the following JSON content inside the “Settings schema” tab of Settings schema section:

{
    "schema": {
        "type": "object",
        "title": "AlarmTableSettings",
        "properties": {
            "alarmSeverityColorFunction": {
                "title": "Alarm severity color function: f(severity)",
                "type": "string",
                "default": "if(severity == 'CRITICAL') {return 'red';} else if (severity == 'MAJOR') {return 'orange';} else return 'green'; "
            }
        },
        "required": []
    },
    "form": [
        {
            "key": "alarmSeverityColorFunction",
            "type": "javascript"
        }
    ]
}

• Put the following JavaScript code inside the “JavaScript” section:

self.onInit = function() {
    self.ctx.$scope.alarmSource = self.ctx.defaultSubscription.alarmSource;
    
    var alarmFields = self.ctx.$scope.$injector.get('types').alarmFields;
    var $filter = self.ctx.$scope.$injector.get('$filter');
    
    var alarmSeverityColorFunctionBody = self.ctx.settings.alarmSeverityColorFunction;
    if (angular.isUndefined(alarmSeverityColorFunctionBody) || !alarmSeverityColorFunctionBody.length) {
        alarmSeverityColorFunctionBody = "if(severity == 'CRITICAL') {return 'red';} else if (severity == 'MAJOR') {return 'orange';} else return 'green';";
    }
    
    var alarmSeverityColorFunction = null;
    try {
        alarmSeverityColorFunction = new Function('severity', alarmSeverityColorFunctionBody);
    } catch (e) {
        alarmSeverityColorFunction = null;
    }

    self.ctx.$scope.getAlarmValue = function(alarm, dataKey) {
        var alarmField = alarmFields[dataKey.name];
        if (alarmField) {
            var value = alarm[alarmField.value];
            if (alarmField.time) {
                return $filter('date')(value, 'yyyy-MM-dd HH:mm:ss');
            } else {
                return value;
            }
        } else {
            return alarm[dataKey.name];
        }
    }
    
    self.ctx.$scope.getAlarmCellStyle = function(alarm, dataKey) {
        var alarmField = alarmFields[dataKey.name];
        if (alarmField && alarmField == alarmFields.severity && alarmSeverityColorFunction) {
            var severity = alarm[alarmField.value];
            var color = alarmSeverityColorFunction(severity);
            return {
                color: color  
            };
        }
        return {};
    }
}

self.onDataUpdated = function() {
    self.ctx.$scope.alarms = self.ctx.defaultSubscription.alarms;
}

• Click on the Run button in the Widget Editor Toolbar in order to see the result in Widget preview section.

In this example the alarmSource and alarms properties of subscription is assigned to the $scope and become accessible within HTML template. Inside the HTML a special ng-repeat angular directive is used in order to iterate over available alarm dataKeys of alarmSource and render corresponding columns. The table rows are rendered by iterating over alarms array and corresponding cells rendered by iterating over dataKeys. The function getAlarmValue is fetching alarm value using special alarmFields constants obtained from types which is part of ThingsBoard UI and accessed via Angular $injector. The function getAlarmCellStyle is used to assign custom cell style for each alarm cell. In this example, we introduced new settings property called alarmSeverityColorFunction that contains function body returning color depending on alarm severity. Inside the getAlarmCellStyle function there is corresponding invocation of alarmSeverityColorFunction with severity value in order to get color for alarm severity cell. Note that in this code onDataUpdated function is implemented in order to update alarms property with latest alarms from subscription.

Static widget

In the Widgets Bundle view click on the big “+” button in the bottom-right part of the screen and then click on the “Create new widget type” button. Click on the Static Widget button in the Select widget type popup. The Widget Editor will be opened pre-populated with the content of default Static template widget.

• Put the following HTML code inside the HTML tab of “Resources” section:

  <div flex layout="column" style="height: 100%;" layout-align="space-around stretch">
      <h3 style="text-align: center;">My first static widget.</h3>
      <md-button class="md-primary md-raised" ng-click="showAlert()">Click me</md-button>
  </div>

• Put the following JSON content inside the “Settings schema” tab of Settings schema section:

{
    "schema": {
        "type": "object",
        "title": "Settings",
        "properties": {
            "alertContent": {
                "title": "Alert content",
                "type": "string",
                "default": "Content derived from alertContent property of widget settings."
            }
        }
    },
    "form": [
        "alertContent"
    ]
}

• Put the following JavaScript code inside the “JavaScript” section:

self.onInit = function() {

    self.ctx.$scope.showAlert = function() {
        var alertContent = self.ctx.settings.alertContent;
        if (!alertContent) {
            alertContent = "Content derived from alertContent property of widget settings.";
        }
        window.alert(alertContent);  
    };

}

• Click on the Run button in the Widget Editor Toolbar in order to see the result in Widget preview section.

This is just a static HTML widget so there is no subscription data or special widget API was used. Only custom showAlert function was implemented showing an alert with the content of alertContent property of widget settings. You can switch to dashboard edit mode in Widget preview section and change value of alertContent by changing widget settings in the “Advanced” tab of widget details. Then you can see that the new alert content is displayed.

Integrating existing code to create widget definition

Below are some examples demonstrating how external JavaScript libraries or existing code can be reused/integrated to create new widgets.

Using external JavaScript library

In this example Latest Values gauge widget will be created using external gauge.js library.

In the Widgets Bundle view click on the big “+” button in the bottom-right part of the screen and then click on the “Create new widget type” button. Click on the Latest Values button in the Select widget type popup. The Widget Editor will be opened pre-populated with the content of default Latest Values template widget.

• Open Resources tab and click “Add” then insert the following link:

http://bernii.github.io/gauge.js/dist/gauge.min.js  

• Clear content of the CSS tab of “Resources” section.
• Put the following HTML code inside the HTML tab of “Resources” section:

  <canvas id="my-gauge"></canvas>

• Put the following JavaScript code inside the “JavaScript” section:

var canvasElement;
var gauge;

self.onInit = function() {
    canvasElement = $('#my-gauge', self.ctx.$container)[0];
    gauge = new Gauge(canvasElement);
    gauge.minValue = -1000; 
    gauge.maxValue = 1000; 
    gauge.animationSpeed = 16; 
    self.onResize();
}

self.onResize = function() {
    canvasElement.width = self.ctx.width;
    canvasElement.height = self.ctx.height;
    gauge.update(true);
    gauge.render();
}

self.onDataUpdated = function() {
    var value = self.ctx.defaultSubscription.data[0].data[0][1];
    gauge.set(value);
}

• Click on the Run button in the Widget Editor Toolbar in order to see the result in Widget preview section.

In this example API of the external JS library was used that become available after injecting the corresponding URL in Resources section. The value displayed was obtained from subscription data property for the first dataKey.

Using existing JavaScript code

Another approach of creating widgets is to use existing bundled JavaScript code. In this case, you can create own JavaScript class or Angular directive and bundle it into the ThingsBoard UI code. In order to make this code accessible within the widget, you need to register corresponding Angular module or inject JavaScript class to a global variable (for ex. window object). Some of the ThingsBoard widgets already use this approach. Take a look at the widget.service.js. Here you can find how some bundled classes or modules are registered for later use in ThingsBoard widgets. For example “Timeseries - Flot” widget (from “Charts” Widgets Bundle) uses TbFlot JavaScript class which is injected as window property inside widget.service.js:

...

import TbFlot from '../widget/lib/flot-widget';
...

    $window.TbFlot = TbFlot;
...

Another example is “Timeseries table” widget (from “Cards” Widgets Bundle) that uses Angular directive tb-timeseries-table-widget which is registered as dependency of ‘thingsboard.api.widget’ Angular module inside widget.service.js. Thereby this directive becomes available for use inside the widget template HTML.

...

import thingsboardTimeseriesTableWidget from '../widget/lib/timeseries-table-widget';

...

export default angular.module('thingsboard.api.widget', ['oc.lazyLoad', thingsboardLedLight, thingsboardTimeseriesTableWidget,

...

Widget code debugging tips

The most simple method of debugging is Web console output. Just place console.log(…) function inside any part of widget JavaScript code. Then click Run button to restart widget code and observe debug information in the Web console.

Another and most effective method of debugging is to invoke browser debugger. Put debugger; statement into the place of widget code you are interested in and then click Run button to restart widget code. Browser debugger (if enabled) will automatically pause code execution at the debugger statement and you will be able to analyze script execution using browser debugging tools.

Next steps

• 入门指南 - 这些指南提供了ThingsBoard主要功能的快速概述。

• 安装指南 - 了解如何在各种操作系统上安装ThingsBoard。

• 设备连接 - 了解如何根据您的连接方式或解决方案连接设备。

• 数据看板 - 这些指南包含有关如何配置复杂的ThingsBoard仪表板的说明。

• 数据处理 - 了解如何使用ThingsBoard规则引擎。

• 数据分析 - 了解如何使用规则引擎执行基本的分析任务。

• 硬件样品 - 了解如何将各种硬件平台连接到ThingsBoard。

• 高级功能 - 了解高级ThingsBoard功能。