Create a "Connect" plugin to integrate Actitime app

[Ronan QUINTIN]

Hello,

I am currently studying documentation on how to create a jira "connect" application which aims at integrate to Actitime app.

Actimetime is basicaly a time track app. In this app we can define Clients / Project / Task. Developpers enters time track on task.

But developpers actually works with Jira issues. So I want to add custom fields to Jira issue to set thoses actitime clients / project and task to an issue at creation.

Then they can time track on jira issues and this time track can be automatically "transfers" to Actitime.

What i've did so far is to use ngrok and spring boot template to create and add an app a test/dev Jira Cloud instance. I can declare a custom fields using this : 

"modules": {
    "jiraIssueFields": [
      {
        "key": "actitime_project",
        "name": {
          "value": "Select actitime project"
        },
        "description": {
          "value": "Select a actitime project"
        },
        "type": "single_select",
        "function": "https://xxx.ngrok-free.app/actitime",
        "searcherKey": "actitime"
      }
    ]
  }

But now I want to populate "actitime project" custom field using my addon rest api. But I am slightly confuse on how to do this.

Somewhere I read that I need to create a IFrame which is use to display HTML code which interacts with Jira API.

Somewhere else I read that I need to use Jira API to "pre-load" select data : 

https://developer.atlassian.com/cloud/jira/platform/rest/v2/api-group-issue-custom-field-options--apps-/#api-rest-api-2-field-fieldkey-option-post

What is recommanded method ? 

Knowing that when I select a client, it changes the list of available projects, which changes the list of available tasks