enter ID in field, let Jira query external API to lookup + fill out additional fields

[Winfred]

Maybe this question has been addressed many times before. If so: apologies!

I would like to (using Jira Core on local server):

• use a screen that has multiple fields. E.g.: userid, first name, last name, homepage URL.
• as soon as the user has entered the userid field, I would like the system to use a predefined REST API call to an external system to return a JSON with the first name, last name and homepage values.
• fill out the associated Jira fields using these JSON values.
• optional: modify the summary field, e.g. "[last name] <original summary>"
• optional: if there was a successful lookup then these additional fields can be made read-only (if not found then the user should be able to enter these additional fields manually)

I checked the marketplace but was not sure if there was an add-on that covers this functionality. We have resources available that can develop. 

[Craig Nodwell]

This would have to work as a scripted solution.  I would recommend scriptrunner