Developing custom widgets

  • Release version: Yokohama
  • Updated January 30, 2025
  • 3 minutes to read
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    Summary of Developing custom widgets

    Develop custom widgets for Service Portal using AngularJS, Bootstrap, and the ServiceNow API to create dynamic, interactive portal components. Widgets enable you to run server-side queries, handle user input, and render data-driven views efficiently. Developing widgets requires proficiency with the ServiceNow API for server interactions and AngularJS for client-side scripting and data binding.

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    Key Components of a Widget

    • HTML Template (mandatory): Uses AngularJS to render the user interface, bind variables, and collect user input.
    • Client Script (mandatory): Implements the client controller using AngularJS and the ServiceNow API to manage data flow between server and UI, process data, and handle user input.
    • Server Script (mandatory): Manages server-side logic such as setting the widget’s initial state and executing database queries using the ServiceNow API.
    • Link Function (optional): Allows direct DOM manipulation using AngularJS when needed.
    • Option Schema (optional): Defines configurable parameters that Service Portal administrators can set per widget instance for customization.
    • Angular Providers (optional): Enable reusable behaviors, shared state, and context across multiple widgets, improving performance and maintainability.
    • Dependencies (optional): External JavaScript or CSS files linked to widgets for extended functionality or styling.

    Data Flow and Global Objects

    The widget lifecycle begins with the server script initializing the data, input, and options objects. The data object is sent to the client controller as JSON. The client uses c.data to access server data and c.options for read-only widget instance settings. Updates from the client are sent back to the server using server.update(), synchronizing data between client and server scripts.

    Development Tools and Practices

    • Widget Editor: A full-page IDE within Service Portal Configuration to edit widget components with real-time preview.
    • ECMAScript 2021 (ES12) Support: Available for server-side scripts to use modern JavaScript features.
    • General Guidelines: Follow best practices to ensure optimal performance, scalability, and user experience.
    • Tutorials and Examples: Use the provided tutorials to build widgets that display Service Catalog items and leverage cloning of existing widgets to accelerate development.

    Advanced Features

    • Widget Option Schema: Allows unique configuration of widget instances by defining customizable parameters.
    • Angular Providers: Support reusable components and shared state to maintain performance and consistency across widgets.
    • Embedded Widgets: Enable nesting of widgets inside HTML templates or scripts for modular design.
    • Widget Dependencies: Link external JavaScript and CSS resources to enhance widget functionality and appearance.
    • Internationalization: Use ${} or gs.getMessage() syntax to tag strings for translation, supporting localization of portal content.
    • Replacing UI Macros: Widgets can replace UI Macros in Service Catalog forms, allowing reusable code and access to variable fields within forms.

    Troubleshooting

    Utilize the recommended tools and guidelines to diagnose and resolve any unexpected behaviors in custom Service Portal widgets effectively.

    Develop custom widgets for portals using AngularJS, Bootstrap, and the ServiceNow API.

    Before you begin

    To develop widgets, you need ServiceNow API experience to:
    • Run record queries on the server.
    • Create and update records.
    You need AngularJS experience to:
    • Bind variables to client controllers.
    • Access server objects in a widget.
    • Gather user input.

    Optionally, you can build on the Bootstrap template by accessing Bootstrap components.

    Parts of a widget

    Like Angular directives, widgets execute a specified behavior within a Service Portal page. A widget includes mandatory and optional scripting components.

    HTML template

    A mandatory widget component.

    The HTML template requires knowledge of AngularJS to display and gather data. Use the HTML template to:

    • Render the dynamic view that a user sees in the browser using information from the model and controller.
    • Bind client script variables to your markup.
    • Gather data from the end user.
    Client script

    A mandatory widget component.

    A client script requires knowledge of both the ServiceNow API and AngularJS to create a client controller. Use the client script to:

    • Map server data from JavaScript and JSON objects to client objects.
    • Process data before rendering it.
    • Pass data to the HTML template.
    • Pass user input and data back to the server for processing.
    Server script

    A mandatory widget component.

    A server script requires knowledge of the ServiceNow API to work with record data. Use the server script to:

    • Set the initial state of the widget.
    • Send record data to the widget client script using the data variable.
    • Run server-side queries.
    Link function

    An optional widget component.

    The link function requires knowledge of AngularJS. Use a link function to directly manipulate the DOM.

    Option schema

    An optional widget component.

    Allows a Service Portal admin to configure a widget. Use the option schema to:

    • Specify the parameters for a widget.
    • Allow admin users to define instance options for a widget instance.
    • Develop flexible, reusable widgets.
    Angular Providers

    An optional widget component.

    Angular Providers require knowledge of AngularJS. Use Angular Providers to:

    • Keep widgets in sync when changing records or filters.
    • Share context between widgets.
    • Maintain and persist state.
    • Create reusable behaviors and UI components and inject them into multiple widgets.
    Dependencies

    An optional widget component.

    A widget dependency is an external resource used by your widget such as JavaScript or CSS files.

    Global objects in widgets

    When a widget begins to render for the first time on a page, the server script executes first and accesses three global objects: input, options, and data. Because the input variable is a data object sent from the client script, this variable is undefined when first initialized.

    Available variables in server and client script global

    When a widget is first instantiated, the server script:

    1. Initializes an empty data object.
    2. Initializes the input object with any data sent from the client controller, or the options object with any data used to initialize the widget.
    3. Sends the data object to the client controller as JSON.

    The client script:

    1. Accesses the server data object using c.data.

      Note:
      By default, widgets use the c variable to represent the controller instance using controller as syntax. You can change this variable when creating or cloning widgets.

    2. Uses server.update() to post changes to the data model. This method updates the server script using the input object.

      Note:
      After calling server.update(), the client script data object is automatically overwritten by the server script data object.
    3. Uses c.options to access the values used to invoke the widget on the server. This object is read-only.

    Using the Widget Editor

    When you create a widget, a record is created in the sp_widget table. However, you can use the Widget Editor in Service Portal Configuration as your scripting environment. The Widget Editor is a full page application similar to an IDE. You can show the parts of the widget you want to edit and hide the rest, while previewing your changes in real time.

    Note:
    For server-side scripts, you can turn on using the ECMAScript 2021 (ES12) JavaScript mode if your application uses ES5 Standards mode or Compatibility mode. Scripts in applications with the JavaScript mode set to ECMAScript 2021 (ES12) use ECMAScript 2021 (ES12) by default. For more information, see Turn on ECMAScript 2021 (ES12) mode for a script.

    Widget editor IDE