It is easy to shoot yourself in the foot when it comes to performanceusing client side scripts. For this reason, it is generally good practice to move any complex processing, large requests more than a hundred or so recordsand multi-level dot-walking to server-side scripts such as business rules which can present the data to the client.
This can be done in a few ways, such as by using GlideAjax. It's also a good idea to utilize callback functions in almost every case where you're doing record lookups client-side. In this article, we'll go over some of the best ways to get the greatest client-side performance out of ServiceNow, by using good coding practices, callback functions, and GlideAjax to push some of the work off onto the server, rather than the client and prevent the client from having to wait around for the server to respond.
This article got a little bit away from me, and ended up being kind of enormous. Therefore, I'll include a little 'index' here, to help you navigate:.
Understanding Client-Side GlideRecord. Callback Functions Asynchronous Queries. Private GlideAjax Functions. Client-Side Encoded Queries. Update : Since ServiceNow removed the ability to do synchronous GlideRecord or GlideAjax calls completelyyou might find yourself in a bind if you need to use GlideAjax or a GlideRecord query in an onSubmit client script.
It provides functions for us to interact with the database, run queries, and so on. Client scripts, are scripts that run inside the user's browser the 'client' when a page is loaded, when a form is modified, or when the form is submitted.
Client-side scripts that execute when a page loads or a field is modified, "block" the user from interacting with the page. Pro Tip : While most scripts only take microseconds or milliseconds to execute, many Client Scripts that run when the page loads should generally be changed to display Business Rules, since they prevent the browser from having to load and work with the form while the user is still waiting.
Callback functions, if you aren't familiar with them, are wondrous things. Once they 'click' in your mind and start making sense, they become the solution to a great many questions.
Callback functions enable asynchronous operations such as querieswhich means queries that don't wait for the server to respond, before returning control of the browser to the user or the rest of the script s on the page. The down-side to client scripts, is that if they don't use a callback function the user must wait for them to finish executing before they can interact with the page.
Their browser effectively 'locks up' the page until all scripts are finished executing. You've probably seen the effects of this yourself when a page SEEMS to be finished loading, but its' browser icon is still "spinning", and you can't interact with it. Pro Tip : You typically want to avoid using a callback function with an onSubmit script. The reason for this is that your browser is the one executing the scripts, and if your script runs "on submit", the browser may leave the page and go about its' business, before your script has finished executing!
Instead, try to figure out if the page should be submitted using other logic on the page that the onSubmit script can access. This is normally not a big deal, because most of our scripts execute in microseconds or a few milliseconds. However, what about when we do something like. In that case, we submit an encoded query representing the query we've built to the server, wait for the server to retrieve the results and process any logic, then return that data to us.
The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. I have a Client Script that performs a GlideRecord query to check if a record already exists with the same name. The issue is that since the callback is asynchronous, it does not actually stop the form from being submitted!
That's because the script proceeds along to submit the form before the callback has a chance to retrieve the value. How can we stop the submission of a form based on the value returned by an asynchronous callback? We're on Helsinki Patch 5 so we're going through similar growing pains. We've had luck using the following structure. Learn more. Asked 3 years, 6 months ago. Active 2 years, 2 months ago. Viewed 4k times. If a matching record is found, we need to STOP the form from being submitted.
We have this working fine on the CMS portal. However, the new Service Portal does not support synchronous GlideRecord query. So I can't use gr. Here is the client script that I am trying to get working in the new Service Portal. Active Oldest Votes. You might try wrapping your Submit action inside of a custom event handler. Try: Client side: c.
John Benedetti John Benedetti 56 5 5 bronze badges.
Thanks so much John. Could you describe the last bit about how to "bind the event handler to some action in the UI"? We just need to validate the form onSubmit so it would be the submit button on a catalog item or a record producer.
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You can modify the ng-click binding on the submit button on line 30 of the HTML section. It really depends on what your design requirements are. I was able to solve this by using an asyc callback with the glide record query. Please enter a different group name. Sign up or log in Sign up using Google.We are experimenting with new training content delivery methods. This tutorial blog post is one of those experiments. We are very interested in your feedback.
Please let us know what you think about this format and the content in the comments below. Newer developers in the Developer Program have requested additional hands-on work with GlideRecord. The topics in this post build on concepts in the Server-side Scripting module.
User Object Cheat Sheet
Replace the contents of the script field with this script. NOTE : this script contains some text you will update in the next step. If you are not sure, scroll to the Answers section at the bottom of this page. NOTE : If you need help with any of these, see the Create an Incident Business Rule section in the answers at the bottom of this post for the complete script.
Did you do the hands-on exercise in this blog? Click here to let us know! Display the list in an information message. If you need help, see the Create a NeedIt Business Rule section in the answers at the bottom of this post for a sample script.
Create a Business Rule for Changes that find and lists other changes opened for the same Configuration Item. Dsiplay the list in an information message. If you need help, see the Create a Change Business Rule section in the answers at the bottom of this post for a sample script. Create an Incident Business Rule : Replace the placeholders in the script with the correct object and methods.
Answer : Pass the table on which to perform the query to the GlideRecord class. Pass the field name, operator, and value to the addQuery method. Create a NeedIt Business Rule : Here is an example script for a Business Rule to get the list of other NeedIt requests for a user and write them to an information message. Create a Change Business Rule : Here is an example script for a Business Rule to get the list of other Changes for a Configuration Item and write them to an information message.
Create a CI Business Rule : Replace the placeholders in the script with the correct table and query parameters. Powered by Hugo. Introduction Newer developers in the Developer Program have requested additional hands-on work with GlideRecord. In this exercise, you create three Business Rules. NOTE : This exercise uses demo data that may vary from your instance.
View Incidents where Rick Berzle is the Caller. Make note of how many records have Rick Berzle as the Caller. Create a Business Rule. Click the New button. Configure the Business Rule.Using methods in the GlideRecord API, you can return all the records in a table, return records based on specific conditions or keywords, or return records from multiple tables with a single query.
Creating a GlideRecord creates a target variable which is a GlideRecord object for the incident table.
This script issues the query to the database. Each call to next would load the next record for processing. For example, this script returns records from the Incident table that include the 'email' keyword. For example, instead of addQueryyou can also use gr.
A text index group is a group of tables that the system indexes together and searches across. For more information about text index groups, see Configure multiple tables for indexing and searching. For example, this script returns records that include the keyword 'email' in the 'portal' index group.
For example, instead of addQueryyou can use gr. Describes the operators that can be used within an addQuery request. For additional information on the operators that are available for filters and queries, see Operators available for filters and queries.
These examples demonstrate how to perform various GlideRecord queries. For additional information see GlideRecord. Note: Before querying a table or an index group, you must configure text indexing and search attributes for one or more tables you want to search.
For more information, see Configure a single table for indexing and searching or Configure multiple tables for indexing and searching.onchange Client Script ServiceNow - ServiceNow onchange Client Script Coding Demonstration
To query a table, first create a GlideRecord object. To process all records from the incident table, add the following script: target. Most of the time, you want to retrieve a specific record or a specific set of records, and you have some criteria query conditions that define the records you want to obtain. For example, say that you want to obtain all the incident records that have a priority value of 1.Sometimes you want to use a gliderecord query from within a client script.
In that case make sure you use a callback function. Looking at the timing diagram below we can see the difference. CS1 needs ms to retrieve the data from the server and then needs around ms to process the result. During all this time the browser cannot do anything else. CS2 needs ms, but is not blocking the next query. Conclusion : in this case we saved the user around ms waiting time, with just a small change in the script.
Thanks for promoting the use of GlideRecord callbacks, it is the preferred method of client queries. Also, when using GlideRecord queries in onLoad scripts you should also see if using display business rules are a better option.
The Fantastic g_form getReference Callback
Recent Comments David : Will this work for Kingston or what would be the equivalent? Herbart Azure : You need to adjust the UI page that performs the removal for You may hav RB : Hi, Don't seem to get it to work that part when you are inThis is an excellent page to keep bookmarked! An easy way to identify the encoded query string to use is to create a filter or a module with the query parameters you want to use, and then hover over the link or breadcrumb and look at the URL.
Is there a way to query for a date? Such as current. You can build the query you want in a module or filter definition to see what the encoded query should look like. SN seems to be all scripting from the get go with limited use of GUIs for configuration. Thanks for the comment. Hopefully some of the content here helps you to get going a little bit faster. I know that the SNC documentation team is really focusing right now on scripting documentation so what you see on the wiki should be getting better by the day.
You might check out these forum links for some more information about SNC scripting basics. In reference to the Or query — is there any documentation about what a QueryCondition object is, and what its other functions are?
There are a couple more examples that I could probably share though. I find the encodedquery to be extremely helpful especially when my query includes things like created this week or created before a specific date.
Then I know for sure I have the right query string. Question: If I run a GlideRecord query and then want to add another condition to the query and rerun it, is that possible? Not that I would do the following but just as an example.
One thing to note about updating a reference field to null is that it has to be done as described here:. Thanks so much for posting this info -it is really helpful!. Here is an example of what we wre trying to accomplish. Did you ever determine a way to do it. The only other way I can think of doing it is to create two separate queries and then combine the results not very pretty but easy enough I suppose.
However, if i leave the line as is, i wont see the update. Anyone have any thoughts? This cheat sheet covers the most frequently used GlideRecord operations. All explanations and examples are easy to follow. It saved me huge amount of time which I may have spent looking through the Service-Now Wiki pages. Can you describe the scenario or area of the tool where this would be used?
I know this was asked a long time ago but here is how you print the current query: gs. So I created an addEncodedQuery and it produced the correct data on the display list but any further filtering on the list is ignored. Is there a solution to these nested conditions, I am currently on Fuji and look to upgrade if required? Hey Peter, this question is probably better suited for ServiceNow support or the ServiceNow community.
But this is not working. How can I reference the manager id to return the Manager name as the Approver?Access fields on a related table from a form, list, or script by dot-walking. This topic includes examples of the different ways you can dot-walk. You can dot-walk to related fields in a list, such as the field list in a filter. This example demonstrates how to filter the Incident [incident] table by the company of the caller who registered the incident.
The example shows that the user is at Incident. You can return to higher levels in the hierarchy by selecting fields located at the top of the menu. For instance, selecting Incident fields returns to the list of incident fields. To dot-walk in a condition builder, first select Show Related Fields on the fields menu.
This action allows you to add fields from related tables to your query. The following GIF shows how you would dot-walk fields in a condition builder to find all Incident records assigned to one specific user, Beth Anglin. The user opens the fields menu again to select Last name.
The user builds the following condition: [Last name] [is] [Anglin]. After the user selects Runthe Incident list displays only the records assigned to Beth Anglin.
Scripting in ServiceNow Fundamentals
Often, you can add variables into templates, notifications, or other forms where a value is being called from the form. As shown in the example, you can dot-walk to fields on the original record of any reference field. The following example shows how you would use a tree picker to assign an Incident record to a user in the Database group.
You would first navigate to any Incident record and then enter Database in the Assignment group field. In this example, the Database group is a parent group with multiple child groups under it. When you select the search icon next to the Assigned to field, a window displays reference fields in the Database group. In this example, expanding the Database Atlanta or Database San Diego fields opens a list of user records within each child group.
You would select any one of the user records to add it as a value in the Assigned to field. List fields You can dot-walk to related fields in a list, such as the field list in a filter. When you open the list of fields that you want to filter, you see the list of available Incident table fields.
The reference fields are followed by the related fields. If the related fields are not present in the list, you would select Show Related Fields at the bottom of the list. When you select Show Related Fieldsthe menu reloads to display related fields. When you select a related field, the menu reloads with the fields of the related table. The following example shows where you are in the dot-walk.
Each selected reference is stored at the top of the fields menu, and the number of dots preceding the field label indicate how many dots from the initial record the user has reached. The related fields can be removed by selecting Remove Related Fields at the bottom of the list. To see which fields are reference fields and can be dot-walked, look for green fields with a plus symbol. Once a reference field is highlighted, the expand icon appears above the add icon.
Selecting the expand icon opens the list of fields from the related list in the Available pane. The following example shows that the Assigned to fields were selected.