Through REST API, How to get RITM and Task values for each Request?

[soibam_ana_sing]

we are integration SNOW with third party platform " Hybrid cloud management" through REST APIs. we use only REST APIs for integration. 

We order Catalog Items through Service catalog APIs(https://docs.servicenow.com/bundle/istanbul-servicenow-platform/page/integrate/inbound-rest/reference/r_SCatAPIAddItemToCartPOST.html#ariaid-title12)  and a request is generated (REQ0010180). Through REST APIs, How would I get RITM and Task values for each Request? 

we don't want to use  client script gliderecord

regards

Soibam

[gale3]

thank you very much. great help.

[Hitoshi Ozawa]

Can create a Scripted REST API to get everything in 1 REST call.

(function process( /*RESTAPIRequest*/ request, /*RESTAPIResponse*/ response) {
    var number = request.pathParams.number;

    var taskInfo = {};
    try {
        var grRTIM = new GlideRecord('sc_req_item');
        if (grRTIM.get('number', number)) {
            taskInfo = {
                'number': number.toString(),
                'item': grRTIM.cat_item.name.toString(),
                'stage': grRTIM.stage.toString(),
                'request': grRTIM.request.number.toString(),
                'requested_for': grRTIM.requested_for.name.toString(),
                'opened_by': grRTIM.opened_by.name.toString(),
                'due_date': grRTIM.due_date.toString(),
                'updated': grRTIM.sys_updated_on.toString()
            };
            var grTask = new GlideRecord('sc_task');
            grTask.addQuery('parent', grRTIM.sys_id);
            grTask.query();
            var taskList = [];
            while (grTask.next()) {
                var taskNumber = grTask.number;
                var taskPriority = grTask.priority;
                taskList.push({
                    'number': grTask.number.toString(),
                    'priority': grTask.priority.toString(),
                    'state': grTask.state.toString(),
                    'short_description': grTask.short_description.toString(),
                    'assignment_group': grTask.assignment_group.name.toString(),
                    'opened': grTask.opened_at.toString()
                });

            }
            //gs.info(JSON.stringify(taskList));
            taskInfo['tasks'] = taskList;
        }
    } catch (e) {
        gs.error("ERROR=", e);
    }
    return taskInfo;
})(request, response);

Example result:

{
  "result": {
    "number": "RITM0010040",
    "item": "mrvs script",
    "stage": "Assess or Scope Task",
    "request": "REQ0010033",
    "requested_for": "System Administrator",
    "opened_by": "System Administrator",
    "due_date": "2020-10-06 09:10:08",
    "updated": "2020-10-04 09:10:10",
    "tasks": [
      {
        "number": "SCTASK0010059",
        "priority": "4",
        "state": "-5",
        "short_description": "Provide requested service",
        "assignment_group": "Software",
        "opened": "2020-10-04 09:10:09"
      },
      {
        "number": "SCTASK0010058",
        "priority": "4",
        "state": "1",
        "short_description": "Assess or Scope Task",
        "assignment_group": "Field Services",
        "opened": "2020-10-04 09:10:08"
      }
    ]
  }
}