Fix for #221 Allow custom WebClient options

src/App.spec.ts

@@ -8,6 +8,7 @@ import rewiremock from 'rewiremock';
 import { ErrorCode } from './errors';
 import { Receiver, ReceiverEvent, SayFn, NextMiddleware } from './types';
 import { ConversationStore } from './conversation-store';
+import { LogLevel } from '@slack/logger';
 
 describe('App', () => {
   describe('constructor', () => {
@@ -155,6 +156,32 @@ describe('App', () => {
         assert(fakeConversationContext.firstCall.calledWith(dummyConvoStore));
       });
     });
+    it('with clientOptions', async () => {
+      const fakeConstructor = sinon.fake()
+      const overrides = mergeOverrides(
+        withNoopAppMetadata(),
+        {
+          '@slack/web-api': {
+            WebClient: class {
+              constructor() {
+                fakeConstructor(...arguments)
+              }
+            },
+          }
+        }
+      )
+      const App = await importApp(overrides);
+
+      const clientOptions = { slackApiUrl: 'proxy.slack.com' };
+      new App({ authorize: noopAuthorize, signingSecret: '', logLevel: LogLevel.ERROR, clientOptions });
+
+      assert.ok(fakeConstructor.called);
+
+      const [token, options] = fakeConstructor.lastCall.args;
+      assert.strictEqual(undefined, token, 'token should be undefined');
+      assert.strictEqual(clientOptions.slackApiUrl, options.slackApiUrl);
+      assert.strictEqual(LogLevel.ERROR, options.logLevel, 'override logLevel');
+    })
     // TODO: tests for ignoreSelf option
     // TODO: tests for logger and logLevel option
     // TODO: tests for providing botId and botUserId options

src/App.ts

@@ -1,5 +1,5 @@
 import util from 'util';
-import { WebClient, ChatPostMessageArguments, addAppMetadata } from '@slack/web-api';
+import { WebClient, ChatPostMessageArguments, addAppMetadata, WebClientOptions } from '@slack/web-api';
 import { Logger, LogLevel, ConsoleLogger } from '@slack/logger';
 import ExpressReceiver, { ExpressReceiverOptions } from './ExpressReceiver';
 import {
@@ -50,6 +50,7 @@ export interface AppOptions {
   logger?: Logger;
   logLevel?: LogLevel;
   ignoreSelf?: boolean;
+  clientOptions?: WebClientOptions;
 }
 
 export { LogLevel, Logger } from '@slack/logger';
@@ -127,14 +128,18 @@ export default class App {
     logger = new ConsoleLogger(),
     logLevel = LogLevel.INFO,
     ignoreSelf = true,
+    clientOptions = undefined,
   }: AppOptions = {}) {
 
     this.logger = logger;
     this.logger.setLevel(logLevel);
     this.errorHandler = defaultErrorHandler(this.logger);
 
-    // TODO: other webclient options (such as proxy)
-    this.client = new WebClient(undefined, { logLevel });
+    let options = { logLevel };
+    if (clientOptions !== undefined) {
+      options = { ...clientOptions, ...options };
+    }
+    this.client = new WebClient(undefined, options);
 
     if (token !== undefined) {
       if (authorize !== undefined) {