How can I invoke an external webservice from a press of a button on a JIRA view issue screen?

[Joseph Malionek]

I am trying to develop a plugin that will send an HTTP PUT request to an external webservice using the content of specific fields of a given issue as the data of the request.

Essentially, it will add a "Print" button onto issue view screens. Once this button is clicked, it should populate a template with content of certain fields (the summary, description, assignee, date created etc..) of the issue it was triggered from.  The populated template should result in JSON format. Then the external webservice should be invoked using the JSON in an HTTP PUT request.

P.S - My instance of JIRA is hosted on our server, not on the cloud so this must be done via a Plugin2 plugin instead of a connect add-on.

[GabrielleJ]

For my instance, I accomplished this via a post-function groovy script. I needed a button that when clicked, will trigger a Jenkins Build. In the post-function, you have a couple options :

• Trigger a Webhook - If this post-function is executed, JIRA will post the issue content in JSON format to the URL specified.
  https://developer.atlassian.com/jiradev/jira-architecture/webhooks
• Script Post-Function - Runs a script in a post-function. 
  https://jamieechlin.atlassian.net/wiki/display/GRV/Post+Functions

I am using the second one which gives me more freedom.