Lecture Notes: ServiceNow Developer Training

Introduction

Instructor: Gaurav Tripathi
Experience: 9.5 years in IT, 6.5 years in ServiceNow
Objective: Train on ServiceNow scripting for developers

Prerequisites

Experience in ServiceNow Administration (6 months) required.
Knowledge of JavaScript.
Completed Code Academy JavaScript course (recommended).

Topics Covered

Client Scripts
UI Policies
Business Rules
Script Includes
Workflows
GlideAjax

Client-Side Scripting

Client-Side Scripts execute within a user’s browser.
Manage forms and form fields (e.g., show an alert on form load, validate form data).

Locations to Write Client-Side Scripts

Client Scripts
UI Policies
Service Catalog UI Policies
UI Actions
UI Context Menus
Validation Scripts

Key Client-Side APIs

GlideForm (g_form)
- Methods: addDecoration, addErrorMessage, addInfoMessage, setMandatory, etc.
GlideUser (g_user)
- Methods: getUserID, getUserName, hasRole, etc.
GlideAjax (g_ajax)
- Used to call server-side code from client side.

Scripting in Business Rules

Server-side scripting
Trigger Points: Insert, Update, Delete, Query
Execution Timings: Before, After, Async, Display
Key Objects: current, previous, GlideAjax, GlideSystem (gs)

Example Business Rule

var gr = new GlideRecord('incident');
gr.addQuery('active', true);
gr.query();
while (gr.next()) {
  gs.log('Active Incident: ' + gr.number);
}

Script Includes

Store reusable JavaScript functions
Executed on server side

Types of Script Includes

Classless: Single reusable function.
Extended Classes: Call functions on the client side using GlideAjax.
Utils: Classes with multiple functions.

Example Script Include

var DemoUtils = Class.create();
DemoUtils.prototype = {
  initialize: function() {},
  calculateSum: function(a, b) {
    return a + b;
  },
  type: 'DemoUtils'
};

Workflows

Automated sequence of activities (e.g., Approvals, Sending Notifications).
Workflow Editor: Interface to create/manage workflows
Scripting in Workflows: Used in different activities like IF conditions, notifications, REST messages, etc.

Example Workflow Script

if (current.priority == 1) {
  workflow.scratchpad.issue_priority = 'High';
}

GlideAjax

Used to make server-side calls from client side scripts
Syntax

var ga = new GlideAjax('ServerScriptInclude');
ga.addParam('sysparm_name', 'getData');
ga.getXMLAnswer(callbackFunction);

Debugging

Tools: JavaScript Log, Field Watcher, Response Time Indicator, Try/Catch
Syntax for Logging: gs.log('Your message');
Catch Errors:

try {
  // code
} catch (ex) { 
  gs.log('Error: ' + ex);
}

Conclusion

Developer Scope: Ability to perform advanced scripting in various ServiceNow functionalities.
Recommendation: Practice the examples, become comfortable with scripting in different scenarios.

Resources

ServiceNow Developer Documentation
Code Academy JavaScript Course
ServiceNow Developer Portal