add stackoverflow api implementation

Signed-off-by: Brian Fletcher <brian@roadie.io>

plugins/stack-overflow/src/api/StackOverflowApi.ts

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2022 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { createApiRef } from '@backstage/core-plugin-api';
+import {
+  StackOverflowQuestion,
+  StackOverflowQuestionsRequestParams,
+} from '../types';
+
+export const stackOverflowApiRef = createApiRef<StackOverflowApi>({
+  id: 'plugin.stackoverflow.service',
+});
+
+export type StackOverflowApi = {
+  listQuestions(options?: {
+    requestParams: StackOverflowQuestionsRequestParams;
+  }): Promise<StackOverflowQuestion[]>;
+};

plugins/stack-overflow/src/api/StackOverflowClient.test.ts

@@ -0,0 +1,74 @@
+/*
+ * Copyright 2021 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { setupRequestMockHandlers } from '@backstage/test-utils';
+import { rest } from 'msw';
+import { setupServer } from 'msw/node';
+import { StackOverflowClient } from './index';
+import { StackOverflowQuestion } from '../types';
+
+const server = setupServer();
+
+const backstageQuestions: StackOverflowQuestion[] = [
+  {
+    title: 'What is it?',
+    link: 'https://example.com:9191/questions/1',
+    tags: ['asdf'],
+    owner: { who: 'me' },
+    answer_count: 3,
+  },
+  {
+    title: 'Is it?',
+    link: 'https://example.com:9191/questions/2',
+    tags: ['asdf'],
+    owner: { who: 'me' },
+    answer_count: 4,
+  },
+];
+
+describe('StackOverflowClient', () => {
+  setupRequestMockHandlers(server);
+
+  const mockBaseUrl = 'https://example.com:9191';
+
+  const setupHandlers = () => {
+    server.use(
+      rest.get(`${mockBaseUrl}/questions`, (req, res, ctx) => {
+        return res(
+          ctx.json({
+            items:
+              req.url.searchParams.get('tagged') === 'backstage'
+                ? backstageQuestions
+                : [],
+          }),
+        );
+      }),
+    );
+  };
+
+  it('list questions should return all questions', async () => {
+    setupHandlers();
+    const client = new StackOverflowClient({
+      baseUrl: 'https://example.com:9191',
+    });
+
+    const responseQuestions = await client.listQuestions({
+      requestParams: { tagged: 'backstage' },
+    });
+    expect(responseQuestions.length).toEqual(2);
+    expect(responseQuestions).toEqual(backstageQuestions);
+  });
+});

plugins/stack-overflow/src/api/StackOverflowClient.ts

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2021 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import fetch from 'cross-fetch';
+import { StackOverflowApi } from './StackOverflowApi';
+import {
+  StackOverflowQuestion,
+  StackOverflowQuestionsRequestParams,
+} from '../types';
+import qs from 'qs';
+
+export class StackOverflowClient implements StackOverflowApi {
+  private baseUrl: string;
+
+  constructor({ baseUrl }: { baseUrl: string }) {
+    this.baseUrl = baseUrl;
+  }
+
+  /**
+   * List Questions in the StackOverflow instance
+   *
+   * */
+  async listQuestions(options: {
+    requestParams: StackOverflowQuestionsRequestParams;
+  }): Promise<StackOverflowQuestion[]> {
+    const params = qs.stringify(options.requestParams, {
+      addQueryPrefix: true,
+    });
+    const response = await fetch(`${this.baseUrl}/questions${params}`);
+    const data = await response.json();
+    return data.items;
+  }
+}

plugins/stack-overflow/src/api/index.ts

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2022 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * An API definition and client for integrating with the StackOverflow Backend
+ * API
+ *
+ * @packageDocumentation
+ */
+
+export * from './StackOverflowApi';
+export * from './StackOverflowClient';

plugins/stack-overflow/src/home/StackOverflowQuestions/Content.tsx

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import { useApi, configApiRef } from '@backstage/core-plugin-api';
+import { useApi } from '@backstage/core-plugin-api';
 import { Link } from '@backstage/core-components';
 import {
   IconButton,
@@ -26,12 +26,12 @@ import {
 } from '@material-ui/core';
 import OpenInNewIcon from '@material-ui/icons/OpenInNew';
 import useAsync from 'react-use/lib/useAsync';
-import qs from 'qs';
 import React from 'react';
 import {
   StackOverflowQuestion,
   StackOverflowQuestionsContentProps,
 } from '../../types';
+import { stackOverflowApiRef } from '../../api';
 
 /**
  * A component to display a list of stack overflow questions on the homepage.
@@ -41,18 +41,12 @@ import {
 
 export const Content = (props: StackOverflowQuestionsContentProps) => {
   const { requestParams } = props;
-  const configApi = useApi(configApiRef);
-  const baseUrl =
-    configApi.getOptionalString('stackoverflow.baseUrl') ||
-    'https://api.stackexchange.com/2.2';
+  const stackOverflowApi = useApi(stackOverflowApiRef);
 
   const { value, loading, error } = useAsync(async (): Promise<
     StackOverflowQuestion[]
   > => {
-    const params = qs.stringify(requestParams, { addQueryPrefix: true });
-    const response = await fetch(`${baseUrl}/questions${params}`);
-    const data = await response.json();
-    return data.items;
+    return await stackOverflowApi.listQuestions({ requestParams });
   }, []);
 
   if (loading) {

plugins/stack-overflow/src/plugin.ts

@@ -17,9 +17,12 @@
 import {
   createPlugin,
   createComponentExtension,
+  createApiFactory,
+  configApiRef,
 } from '@backstage/core-plugin-api';
 import { createCardExtension } from '@backstage/plugin-home';
 import { StackOverflowQuestionsContentProps } from './types';
+import { stackOverflowApiRef, StackOverflowClient } from './api';
 
 /**
  * The Backstage plugin that holds stack overflow specific components
@@ -28,6 +31,18 @@ import { StackOverflowQuestionsContentProps } from './types';
  */
 export const stackOverflowPlugin = createPlugin({
   id: 'stack-overflow',
+  apis: [
+    createApiFactory({
+      api: stackOverflowApiRef,
+      deps: { configApi: configApiRef },
+      factory: ({ configApi }) =>
+        new StackOverflowClient({
+          baseUrl:
+            configApi.getOptionalString('stackoverflow.baseUrl') ||
+            'https://api.stackexchange.com/2.2',
+        }),
+    }),
+  ],
 });
 
 /**