ServiceNow Expert
Core Concepts
ServiceNow Platform
- ITSM - IT Service Management (Incident, Problem, Change)
- ITOM - IT Operations Management
- ITBM - IT Business Management
- CMDB - Configuration Management Database
- Service Portal - User-facing portal interface
- Flow Designer - Visual workflow automation
Development Components
- Business Rules - Server-side scripts on table operations
- Client Scripts - Client-side validation and logic
- UI Policies - Dynamic form behavior
- Script Includes - Reusable server-side code libraries
- Scheduled Jobs - Automated background tasks
- Transform Maps - Data import/integration mapping
Scripting APIs
- GlideRecord - Database query and manipulation
- GlideAjax - Asynchronous client-server communication
- GlideSystem - System utilities (gs object)
- GlideDateTime - Date and time operations
- GlideUser - User information and permissions
- RESTMessageV2 - External API integration
Implementation Examples
GlideRecord Query and Update
// Business Rule - Update related records
(function executeRule(current, previous /*null when async*/) {
// Query for related incidents
var gr = new GlideRecord('incident');
gr.addQuery('caller_id', current.sys_id);
gr.addQuery('state', 'IN', '1,2,3'); // New, In Progress, On Hold
gr.query();
var incidentCount = 0;
var incidentNumbers = [];
while (gr.next()) {
// Update priority based on user's VIP status
if (current.vip == true) {
gr.priority = '1'; // Critical
gr.update();
incidentCount++;
incidentNumbers.push(gr.number.toString());
}
}
// Log activity
if (incidentCount > 0) {
gs.addInfoMessage(
'Updated ' + incidentCount + ' incidents: ' + incidentNumbers.join(', ')
);
gs.info(
'VIP status updated for user ' +
current.sys_id +
', affected incidents: ' +
incidentNumbers.join(', ')
);
}
})(current, previous);
Script Include with REST API Integration
var ExternalAPIIntegration = Class.create();
ExternalAPIIntegration.prototype = Object.extendsObject(AbstractAjaxProcessor, {
// Call external API to get user data
getUserDetails: function (userId) {
try {
var request = new sn_ws.RESTMessageV2();
request.setEndpoint('https://api.example.com/users/' + userId);
request.setHttpMethod('GET');
request.setRequestHeader('Accept', 'application/json');
request.setRequestHeader('Authorization', 'Bearer ' + this._getToken());
var response = request.execute();
var httpStatus = response.getStatusCode();
if (httpStatus == 200) {
var responseBody = response.getBody();
var jsonResponse = JSON.parse(responseBody);
return jsonResponse;
} else {
gs.error('API call failed with status: ' + httpStatus);
return null;
}
} catch (ex) {
gs.error('Exception in getUserDetails: ' + ex.message);
return null;
}
},
// Sync user from external system
syncUser: function (userId) {
var userData = this.getUserDetails(userId);
if (userData) {
var gr = new GlideRecord('sys_user');
gr.addQuery('employee_number', userData.employeeId);
gr.query();
if (gr.next()) {
gr.email = userData.email;
gr.phone = userData.phone;
gr.department = this._getDepartmentId(userData.department);
gr.title = userData.jobTitle;
gr.update();
gs.info('User synced successfully: ' + gr.sys_id);
return gr.sys_id.toString();
} else {
gs.warn('User not found in ServiceNow: ' + userData.employeeId);
return null;
}
}
return null;
},
_getToken: function () {
// Retrieve from system property or credential store
return gs.getProperty('external.api.token');
},
_getDepartmentId: function (deptName) {
var gr = new GlideRecord('cmn_department');
gr.addQuery('name', deptName);
gr.query();
if (gr.next()) {
return gr.sys_id.toString();
}
return '';
},
type: 'ExternalAPIIntegration',
});
Client Script with GlideAjax
// Client Script - onChange
function onChange(control, oldValue, newValue, isLoading, isTemplate) {
if (isLoading || newValue === '') {
return;
}
// Call server-side script to validate user
var ga = new GlideAjax('UserValidationAjax');
ga.addParam('sysparm_name', 'validateUser');
ga.addParam('sysparm_user_id', newValue);
ga.getXMLAnswer(function (answer) {
var result = JSON.parse(answer);
if (!result.valid) {
g_form.showErrorBox('caller_id', result.message);
g_form.clearValue('caller_id');
} else {
// Populate additional fields
g_form.setValue('caller_phone', result.phone);
g_form.setValue('caller_email', result.email);
// Show info message
g_form.addInfoMessage('User validated: ' + result.name);
}
});
}
// Script Include for GlideAjax
var UserValidationAjax = Class.create();
UserValidationAjax.prototype = Object.extendsObject(AbstractAjaxProcessor, {
validateUser: function () {
var userId = this.getParameter('sysparm_user_id');
var result = {
valid: false,
message: '',
};
var gr = new GlideRecord('sys_user');
if (gr.get(userId)) {
if (!gr.active) {
result.message = 'User is inactive';
} else if (gr.locked_out) {
result.message = 'User account is locked';
} else {
result.valid = true;
result.name = gr.name.toString();
result.phone = gr.phone.toString();
result.email = gr.email.toString();
}
} else {
result.message = 'User not found';
}
return JSON.stringify(result);
},
type: 'UserValidationAjax',
});
Service Portal Widget
// Server Script
(function () {
/* Server-side script */
data.incidents = [];
var gr = new GlideRecord('incident');
gr.addQuery('caller_id', gs.getUserID());
gr.addQuery('active', true);
gr.orderByDesc('sys_created_on');
gr.setLimit(10);
gr.query();
while (gr.next()) {
data.incidents.push({
number: gr.getValue('number'),
short_description: gr.getValue('short_description'),
state: gr.getDisplayValue('state'),
priority: gr.getDisplayValue('priority'),
sys_id: gr.getValue('sys_id'),
sys_created_on: gr.getValue('sys_created_on'),
});
}
data.canCreateIncident = gs.hasRole('itil');
})();
<!-- HTML Template -->
<div class="panel panel-default">
<div class="panel-heading">
<h3 class="panel-title">My Incidents</h3>
</div>
<div class="panel-body">
<div ng-if="data.incidents.length === 0" class="alert alert-info">
No active incidents found
</div>
<table class="table table-striped" ng-if="data.incidents.length > 0">
<thead>
<tr>
<th>Number</th>
<th>Description</th>
<th>State</th>
<th>Priority</th>
<th>Created</th>
</tr>
</thead>
<tbody>
<tr ng-repeat="incident in data.incidents">
<td>
<a href="?id=ticket&table=incident&sys_id={{incident.sys_id}}">
{{incident.number}}
</a>
</td>
<td>{{incident.short_description}}</td>
<td>{{incident.state}}</td>
<td>{{incident.priority}}</td>
<td>{{incident.sys_created_on | date:'short'}}</td>
</tr>
</tbody>
</table>
<button
ng-if="data.canCreateIncident"
class="btn btn-primary"
ng-click="c.createIncident()"
>
Create New Incident
</button>
</div>
</div>
// Client Controller
function($scope, spModal) {
var c = this;
c.createIncident = function() {
spModal.open({
title: 'Create Incident',
widget: 'widget-sc-cat-item',
widgetInput: {
sys_id: 'incident_form_sys_id'
}
}).then(function(response) {
// Refresh widget after creation
c.server.refresh();
});
};
}
Flow Designer Action
// Script step in Flow Designer
(function execute(inputs, outputs) {
var incidentId = inputs.incident_id;
var gr = new GlideRecord('incident');
if (gr.get(incidentId)) {
// Calculate business hours since creation
var schedule = new GlideSchedule();
var scheduleId = gr.assignment_group.schedule.toString();
if (scheduleId) {
schedule.load(scheduleId);
} else {
// Default to 24x7
schedule.load('08fcd0930a0a0b00079c3ee8a4efc9ba');
}
var createdDate = gr.sys_created_on.getGlideObject();
var currentDate = new GlideDateTime();
var duration = schedule.duration(createdDate, currentDate);
var hours = duration.getDurationValue() / 3600; // Convert to hours
outputs.business_hours = hours;
outputs.is_sla_breach = hours > 24; // SLA is 24 hours
// Update incident
gr.u_business_hours_open = hours;
gr.update();
} else {
outputs.business_hours = 0;
outputs.is_sla_breach = false;
gs.error('Incident not found: ' + incidentId);
}
})(inputs, outputs);
Best Practices
Development Standards
- Follow ServiceNow coding best practices
- Use Script Includes for reusable code
- Implement proper error handling
- Add comments and documentation
- Use meaningful variable names
- Avoid global business rules when possible
Performance Optimization
- Limit GlideRecord queries (use setLimit)
- Use encoded queries for complex conditions
- Avoid nested queries and loops
- Implement caching where appropriate
- Use async business rules for non-critical updates
- Index frequently queried fields
Security Best Practices
- Implement ACLs for data access control
- Validate user input on client and server
- Use GlideRecord instead of direct SQL
- Follow principle of least privilege
- Sanitize data before display
- Use encrypted fields for sensitive data
Integration Patterns
- Use REST API for modern integrations
- Implement proper error handling and retry logic
- Use credentials store for API keys
- Log integration activities
- Implement rate limiting
- Use MID Server for on-premise connectivity
Anti-Patterns
Code Smells
- Complex business rules with too much logic
- Client scripts that make synchronous GlideAjax calls
- Hardcoded sys_ids in scripts
- Missing null checks on GlideRecord queries
- Global variables without proper scoping
- Direct DOM manipulation in Service Portal
Performance Issues
- Queries without limits on large tables
- Synchronous business rules that slow transactions
- Missing indexes on custom fields
- Recursive business rule triggers
- Loading unnecessary related records
- Heavy client scripts on form load
Design Issues
- Tight coupling between components
- No separation of concerns
- Monolithic Script Includes
- Duplicated code across multiple scripts
- Poor error handling strategy
- Missing logging and debugging info
Resources
Official Documentation
Learning Platforms
Tools & Resources
Community Resources
