[Cases ]Expose the bulk get cases API from the cases UI client (#154235)

## Summary

This PR exposes the bulk get cases API from the cases UI client.

Fixes: https://github.com/elastic/kibana/issues/153926

### Checklist

Delete any items that are not applicable to this PR.

- [x] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios

### For maintainers

- [x] This was checked for breaking API changes and was [labeled
appropriately](https://www.elastic.co/guide/en/kibana/master/contributing.html#kibana-release-notes-process)

---------

Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>

x-pack/plugins/cases/public/api/decoders.ts

@@ -15,10 +15,14 @@ import type {
   CasesFindResponse,
   CasesStatusResponse,
   CasesMetricsResponse,
+  CasesBulkGetResponseCertainFields,
+  CaseResponse,
 } from '../../common/api';
 import {
   CasesFindResponseRt,
   CasesStatusResponseRt,
+  CasesResponseRt,
+  getTypeForCertainFieldsFromArray,
   CasesMetricsResponseRt,
 } from '../../common/api';
 
@@ -36,3 +40,13 @@ export const decodeCasesMetricsResponse = (metrics?: CasesMetricsResponse) =>
     CasesMetricsResponseRt.decode(metrics),
     fold(throwErrors(createToasterPlainError), identity)
   );
+
+export const decodeCasesBulkGetResponse = <Field extends keyof CaseResponse = keyof CaseResponse>(
+  res: CasesBulkGetResponseCertainFields<Field>,
+  fields?: string[]
+) => {
+  const typeToDecode = getTypeForCertainFieldsFromArray(CasesResponseRt, fields);
+  pipe(typeToDecode.decode(res.cases), fold(throwErrors(createToasterPlainError), identity));
+
+  return res;
+};

x-pack/plugins/cases/public/api/index.test.ts

@@ -6,8 +6,8 @@
  */
 
 import { httpServiceMock } from '@kbn/core/public/mocks';
-import { getCases, getCasesMetrics } from '.';
-import { allCases, allCasesSnake } from '../containers/mock';
+import { bulkGetCases, getCases, getCasesMetrics } from '.';
+import { allCases, allCasesSnake, casesSnake } from '../containers/mock';
 
 describe('api', () => {
   beforeEach(() => {
@@ -47,4 +47,31 @@ describe('api', () => {
       });
     });
   });
+
+  describe('bulkGetCases', () => {
+    const http = httpServiceMock.createStartContract({ basePath: '' });
+    http.post.mockResolvedValue({ cases: [{ title: 'test' }], errors: [] });
+
+    it('should return the correct cases with a subset of fields', async () => {
+      expect(await bulkGetCases({ http, params: { ids: ['test'], fields: ['title'] } })).toEqual({
+        cases: [{ title: 'test' }],
+        errors: [],
+      });
+    });
+
+    it('should return the correct cases with all fields', async () => {
+      http.post.mockResolvedValueOnce({ cases: casesSnake, errors: [] });
+      expect(await bulkGetCases({ http, params: { ids: ['test'] } })).toEqual({
+        cases: casesSnake,
+        errors: [],
+      });
+    });
+
+    it('should have been called with the correct path', async () => {
+      await bulkGetCases({ http, params: { ids: ['test'], fields: ['title'] } });
+      expect(http.post).toHaveBeenCalledWith('/internal/cases/_bulk_get', {
+        body: '{"ids":["test"],"fields":["title"]}',
+      });
+    });
+  });
 });

x-pack/plugins/cases/public/api/index.ts

@@ -7,8 +7,16 @@
 
 import type { HttpStart } from '@kbn/core/public';
 import type { Cases, CasesStatus, CasesMetrics } from '../../common/ui';
-import { CASE_FIND_URL, CASE_METRICS_URL, CASE_STATUS_URL } from '../../common/constants';
+import {
+  CASE_FIND_URL,
+  CASE_METRICS_URL,
+  CASE_STATUS_URL,
+  INTERNAL_BULK_GET_CASES_URL,
+} from '../../common/constants';
 import type {
+  CaseResponse,
+  CasesBulkGetRequestCertainFields,
+  CasesBulkGetResponseCertainFields,
   CasesFindRequest,
   CasesFindResponse,
   CasesMetricsRequest,
@@ -18,6 +26,7 @@ import type {
 } from '../../common/api';
 import { convertAllCasesToCamel, convertToCamelCase } from './utils';
 import {
+  decodeCasesBulkGetResponse,
   decodeCasesFindResponse,
   decodeCasesMetricsResponse,
   decodeCasesStatusResponse,
@@ -58,3 +67,21 @@ export const getCasesMetrics = async ({
   const res = await http.get<CasesMetricsResponse>(CASE_METRICS_URL, { signal, query });
   return convertToCamelCase(decodeCasesMetricsResponse(res));
 };
+
+export const bulkGetCases = async <Field extends keyof CaseResponse = keyof CaseResponse>({
+  http,
+  signal,
+  params,
+}: HTTPService & { params: CasesBulkGetRequestCertainFields<Field> }): Promise<
+  CasesBulkGetResponseCertainFields<Field>
+> => {
+  const res = await http.post<CasesBulkGetResponseCertainFields<Field>>(
+    INTERNAL_BULK_GET_CASES_URL,
+    {
+      body: JSON.stringify({ ...params }),
+      signal,
+    }
+  );
+
+  return decodeCasesBulkGetResponse(res, params.fields);
+};

x-pack/plugins/cases/public/client/api/index.test.ts

@@ -7,7 +7,7 @@
 
 import { httpServiceMock } from '@kbn/core/public/mocks';
 import { createClientAPI } from '.';
-import { allCases, allCasesSnake } from '../../containers/mock';
+import { allCases, allCasesSnake, casesSnake } from '../../containers/mock';
 
 describe('createClientAPI', () => {
   beforeEach(() => {
@@ -80,5 +80,33 @@ describe('createClientAPI', () => {
         });
       });
     });
+
+    describe('bulkGet', () => {
+      const http = httpServiceMock.createStartContract({ basePath: '' });
+      const api = createClientAPI({ http });
+      http.post.mockResolvedValue({ cases: [{ title: 'test' }], errors: [] });
+
+      it('should return the correct cases with a subset of fields', async () => {
+        expect(await api.cases.bulkGet({ ids: ['test'], fields: ['title'] })).toEqual({
+          cases: [{ title: 'test' }],
+          errors: [],
+        });
+      });
+
+      it('should return the correct cases with all fields', async () => {
+        http.post.mockResolvedValueOnce({ cases: casesSnake, errors: [] });
+        expect(await api.cases.bulkGet({ ids: ['test'], fields: ['title'] })).toEqual({
+          cases: casesSnake,
+          errors: [],
+        });
+      });
+
+      it('should have been called with the correct path', async () => {
+        await api.cases.bulkGet({ ids: ['test'], fields: ['title'] });
+        expect(http.post).toHaveBeenCalledWith('/internal/cases/_bulk_get', {
+          body: '{"ids":["test"],"fields":["title"]}',
+        });
+      });
+    });
   });
 });

x-pack/plugins/cases/public/client/api/index.ts

@@ -15,7 +15,7 @@ import type {
 } from '../../../common/api';
 import { getCasesFromAlertsUrl } from '../../../common/api';
 import type { Cases, CasesStatus, CasesMetrics } from '../../../common/ui';
-import { getCases, getCasesMetrics, getCasesStatus } from '../../api';
+import { bulkGetCases, getCases, getCasesMetrics, getCasesStatus } from '../../api';
 import type { CasesUiStart } from '../../types';
 
 export const createClientAPI = ({ http }: { http: HttpStart }): CasesUiStart['api'] => {
@@ -32,6 +32,7 @@ export const createClientAPI = ({ http }: { http: HttpStart }): CasesUiStart['ap
         getCasesStatus({ http, query, signal }),
       getCasesMetrics: (query: CasesMetricsRequest, signal?: AbortSignal): Promise<CasesMetrics> =>
         getCasesMetrics({ http, signal, query }),
+      bulkGet: (params, signal?: AbortSignal) => bulkGetCases({ http, signal, params }),
     },
   };
 };

x-pack/plugins/cases/public/mocks.ts

@@ -10,7 +10,12 @@ import type { CasesUiStart } from './types';
 
 const apiMock: jest.Mocked<CasesUiStart['api']> = {
   getRelatedCases: jest.fn(),
-  cases: { find: jest.fn(), getCasesMetrics: jest.fn(), getCasesStatus: jest.fn() },
+  cases: {
+    find: jest.fn(),
+    getCasesMetrics: jest.fn(),
+    getCasesStatus: jest.fn(),
+    bulkGet: jest.fn(),
+  },
 };
 
 const uiMock: jest.Mocked<CasesUiStart['ui']> = {

x-pack/plugins/cases/public/types.ts

@@ -25,6 +25,9 @@ import type { LicensingPluginStart } from '@kbn/licensing-plugin/public';
 import type { FilesSetup, FilesStart } from '@kbn/files-plugin/public';
 import type { SavedObjectsManagementPluginStart } from '@kbn/saved-objects-management-plugin/public';
 import type {
+  CaseResponse,
+  CasesBulkGetRequestCertainFields,
+  CasesBulkGetResponseCertainFields,
   CasesByAlertId,
   CasesByAlertIDRequest,
   CasesFindRequest,
@@ -102,6 +105,10 @@ export interface CasesUiStart {
       find: (query: CasesFindRequest, signal?: AbortSignal) => Promise<Cases>;
       getCasesStatus: (query: CasesStatusRequest, signal?: AbortSignal) => Promise<CasesStatus>;
       getCasesMetrics: (query: CasesMetricsRequest, signal?: AbortSignal) => Promise<CasesMetrics>;
+      bulkGet: <Field extends keyof CaseResponse = keyof CaseResponse>(
+        params: CasesBulkGetRequestCertainFields<Field>,
+        signal?: AbortSignal
+      ) => Promise<CasesBulkGetResponseCertainFields<Field>>;
     };
   };
   ui: {

x-pack/plugins/cases/server/client/cases/client.ts

@@ -66,8 +66,8 @@ export interface CasesSubClient {
    * Retrieves multiple cases with the specified IDs.
    */
   bulkGet<Field extends keyof CaseResponse = keyof CaseResponse>(
-    params: CasesBulkGetRequestCertainFields<Field | 'id' | 'version' | 'owner'>
-  ): Promise<CasesBulkGetResponseCertainFields<Field | 'id' | 'version' | 'owner'>>;
+    params: CasesBulkGetRequestCertainFields<Field>
+  ): Promise<CasesBulkGetResponseCertainFields<Field>>;
   /**
    * Pushes a specific case to an external system.
    */