Advanced Server-Side Scripting in ServiceNow: Best Practices

Server-side scripts in ServiceNow are a crucial element in automating processes, manipulating data, and integrating with other systems. In this article, we will discuss advanced server-side scripting techniques, focusing on the use of GlideSystem, GlideRecord, and GlideAggregate.

1. GlideSystem (gs)

GlideSystem (gs) is a powerful tool that provides access to many system functions in ServiceNow, such as logging, manipulating dates, generating unique identifiers, and controlling transactions. Here are some examples of advanced uses of GlideSystem:

Logging and Debugging:

gs.log("This is an informational log message");
gs.warn("This is a warning");
gs.error("This is an error");

Manipulating Dates:

var now = new GlideDateTime();
gs.addDays(now, 5);
gs.log("Date five days from now: " + now);

Generating Unique IDs:

var uniqueID = gs.generateGUID();
gs.log("Generated unique ID: " + uniqueID);

2. GlideRecord

GlideRecord is the most important tool for manipulating data in ServiceNow tables. It allows you to perform CRUD (Create, Read, Update, Delete) operations on records. Here are some advanced techniques for using GlideRecord:

Creating and Updating Records:

var gr = new GlideRecord('incident');
gr.initialize();
gr.short_description = 'New incident';
gr.insert();

var updateGr = new GlideRecord('incident');
updateGr.get('sys_id', '1234567890abcdef');
if (updateGr.isValidRecord()) {
  updateGr.short_description = 'Updated incident';
  updateGr.update();
}

Filtering and Retrieving Records:

var gr = new GlideRecord('incident');
gr.addQuery('priority', 1);
gr.addQuery('state', '!=', 7);
gr.query();
while (gr.next()) {
  gs.log('Incident: ' + gr.number + ', Description: ' + gr.short_description);
}

Deleting Records:

var gr = new GlideRecord('incident');
gr.addQuery('priority', 5);
gr.query();
while (gr.next()) {
  gr.deleteRecord();
}

3. GlideAggregate

GlideAggregate is used for performing advanced aggregate operations on data, such as summing, counting, averaging, and other statistical operations. Here are examples of advanced uses of GlideAggregate:

Summing and Counting Records:

var ga = new GlideAggregate('incident');
ga.addAggregate('COUNT');
ga.addAggregate('SUM', 'priority');
ga.query();
if (ga.next()) {
  gs.log('Number of incidents: ' + ga.getAggregate('COUNT'));
  gs.log('Sum of priorities: ' + ga.getAggregate('SUM', 'priority'));
}

Grouping and Aggregating:

var ga = new GlideAggregate('incident');
ga.groupBy('priority');
ga.addAggregate('COUNT');
ga.query();
while (ga.next()) {
  gs.log('Priority: ' + ga.priority + ', Number of incidents: ' + ga.getAggregate('COUNT'));
}

Best Practices

• Writing Clear and Understandable Scripts: Always use understandable variable and function names. Comment your code so that other developers can easily understand what the script does.
• Optimizing Queries: Avoid unnecessary database queries. Use methods such as addQuery, addEncodedQuery, and setLimit to limit the number of retrieved records.
• Script Security: Always check if the user has the appropriate permissions to perform the operation. Avoid using gs.runAs unless absolutely necessary.
• Testing and Debugging: Regularly test your scripts in various scenarios. Use gs.log for debugging and error tracking.
• Avoid Hardcoding: Avoid hardcoding values in scripts. Instead, use system properties or configuration variables.

Summary

In summary, advanced server-side scripts in ServiceNow offer enormous potential for automating and optimizing business processes. The key to success is understanding and correctly applying tools such as GlideSystem, GlideRecord, and GlideAggregate, as well as adhering to best programming practices.