Merge pull request #195 from kafkajs/set-user-agent-header

Send user-agent header with API requests

src/api/index.spec.ts

@@ -0,0 +1,23 @@
+import API from '.'
+import { mockClient, install, uninstall } from 'mappersmith/test'
+
+const client = API({ clientId: 'test-client', host: 'http://example.com' })
+const mock = mockClient<typeof client>(client)
+  .resource('Schema')
+  .method('find')
+  .with({ id: 'abc' })
+  .response({})
+  .assertObject()
+
+describe('API Client', () => {
+  beforeEach(() => install())
+
+  afterEach(() => uninstall())
+
+  it('should include a user agent header', async () => {
+    const response = await client.Schema.find({ id: 'abc' })
+
+    expect(mock.callsCount()).toBe(1)
+    expect(response.request().header('User-Agent')).not.toBeUndefined()
+  })
+})

src/api/index.ts

@@ -6,6 +6,7 @@ import BasicAuthMiddleware from 'mappersmith/middleware/basic-auth'
 import { DEFAULT_API_CLIENT_ID } from '../constants'
 import errorMiddleware from './middleware/errorMiddleware'
 import confluentEncoder from './middleware/confluentEncoderMiddleware'
+import userAgentMiddleware from './middleware/userAgent'
 
 const DEFAULT_RETRY = {
   maxRetryTimeInSecs: 5,
@@ -43,17 +44,19 @@ export type SchemaRegistryAPIClient = Client<{
 
 export default ({
   auth,
-  clientId,
+  clientId: userClientId,
   host,
   retry = {},
   agent,
 }: SchemaRegistryAPIClientArgs): SchemaRegistryAPIClient => {
+  const clientId = userClientId || DEFAULT_API_CLIENT_ID
   // FIXME: ResourcesType typings is not exposed by mappersmith
   const manifest: Options<any> = {
-    clientId: clientId || DEFAULT_API_CLIENT_ID,
+    clientId,
     ignoreGlobalMiddleware: true,
     host,
     middleware: [
+      userAgentMiddleware,
       confluentEncoder,
       RetryMiddleware(Object.assign(DEFAULT_RETRY, retry)),
       errorMiddleware,

src/api/middleware/userAgent.spec.ts

@@ -0,0 +1,53 @@
+import { Request } from 'mappersmith'
+
+import UserAgentMiddleware from './userAgent'
+
+const middlewareParams = (clientId?: string) => ({
+  resourceName: 'resourceNameMock',
+  resourceMethod: 'resourceMethodMock',
+  context: { context: 'contextMock' },
+  clientId,
+})
+
+describe('UserAgentMiddleware', () => {
+  let next, request
+
+  beforeEach(() => {
+    request = ({
+      enhance: jest.fn(),
+    } as unknown) as jest.Mocked<Request>
+    next = jest.fn().mockResolvedValue(request)
+  })
+
+  describe('When the user has provided a clientId', () => {
+    const params = middlewareParams('some-client-id')
+
+    it('should add the client id as a user agent comment', async () => {
+      const middleware = UserAgentMiddleware(params)
+
+      await middleware.prepareRequest(next, jest.fn())
+
+      expect(request.enhance).toHaveBeenCalledWith({
+        headers: {
+          'User-Agent': `@kafkajs/confluent-schema-registry (${params.clientId})`,
+        },
+      })
+    })
+  })
+
+  describe('When the user has not provided a clientId', () => {
+    const params = middlewareParams()
+
+    it('should not include a comment in the user agent', async () => {
+      const middleware = UserAgentMiddleware(params)
+
+      await middleware.prepareRequest(next, jest.fn())
+
+      expect(request.enhance).toHaveBeenCalledWith({
+        headers: {
+          'User-Agent': `@kafkajs/confluent-schema-registry`,
+        },
+      })
+    })
+  })
+})

src/api/middleware/userAgent.ts

@@ -0,0 +1,19 @@
+import { Middleware } from 'mappersmith'
+import { DEFAULT_API_CLIENT_ID } from '../../constants'
+
+const product = '@kafkajs/confluent-schema-registry'
+
+const userAgentMiddleware: Middleware = ({ clientId }) => {
+  const comment = clientId !== DEFAULT_API_CLIENT_ID ? clientId : undefined
+  const userAgent = comment ? `${product} (${comment})` : product
+  const headers = {
+    'User-Agent': userAgent,
+  }
+  return {
+    prepareRequest: next => {
+      return next().then(req => req.enhance({ headers }))
+    },
+  }
+}
+
+export default userAgentMiddleware