Lecture Notes on ServiceNow Scripting

Overview of Scripting in ServiceNow

• Key Concepts:
  • GlideRecord: Used to interact with the database.
  • GlideAjax: Allows client-side scripts to call server-side scripts (Script Includes).
  • Script Includes: Reusable server-side scripts that can be called from other scripts.

GlideRecord

• Used to perform CRUD operations on ServiceNow tables.
• Example usage:

  var gr = new GlideRecord('incident');
  gr.addQuery('active', true);
  gr.query();
  while (gr.next()) {
      // Process each record
  }
  

GlideAjax

• Used to call Script Includes from client-side scripts.
• Example usage:

  var ga = new GlideAjax('YourScriptIncludeName');
  ga.addParam('sysparm_name', 'functionName');
  ga.getXMLAnswer(function(response) {
      // Handle response
  });
  

Script Includes

• Can be defined as client callable or server-side only.
• Structure:

  var YourScriptIncludeName = Class.create();
  YourScriptIncludeName.prototype = {
      initialize: function() {},
      yourFunction: function() {
          // Your logic here
      },
      type: 'YourScriptIncludeName'
  };
  

Client Scripts

• Types:
  • onLoad: Runs when the form loads.
  • onChange: Runs when a field value changes.
  • onSubmit: Runs when the form is submitted.

Business Rules

• Run logic on the server-side when database actions occur (insert, update, delete).
• Types:
  • Before: Runs before the record is saved.
  • After: Runs after the record is saved.
  • Async: Runs asynchronously after the record is saved.
  • Query: A condition to query the records.
• Example:

  (function executeRule(current, previous /*null when async*/) {
      // Business logic here
  })(current, previous);
  

Access Control Lists (ACLs)

• Control access to records, fields, and tables.
• Types:
  • Table-level ACLs: Control access to entire tables.
  • Field-level ACLs: Control access to specific fields in a table.
• Example condition:
  • Only allow users with a specific role to access certain records.

Display Business Rules

• Specific type of business rule that runs when a form is displayed to the user.
• Used to set field values or perform actions when a form loads.

Example Scenarios

• Duplicate Request Validation:
  • Using GlideAjax to call a Script Include to check for duplicate requests.
• User Permissions:
  • Using ACLs to restrict access based on user roles and active status.

Important Functions & Methods

• getValue(): Retrieves the current value of a field.
• setValue(): Sets a new value for a field.
• addQuery(): Adds a query condition to a GlideRecord.
• addEncodedQuery(): Adds a query condition using a string format.

Conclusion

• Understanding the use of GlideRecord, GlideAjax, Script Includes, Business Rules, ACLs, and UI Policies is crucial for effective ServiceNow scripting.
• Practice using these concepts to solidify understanding.