(core) Add welcomeQuestionsSubmitted telemetry event

Summary:
The new event captures responses to the welcome questionnaire.

Responses are also still sent to the special Grist document configured with
the DOC_ID_NEW_USER_INFO variable.

Test Plan: Tested manually.

Reviewers: jarek

Reviewed By: jarek

Differential Revision: https://phab.getgrist.com/D4034

app/server/lib/FlexServer.ts

@@ -53,7 +53,7 @@ import {addPluginEndpoints, limitToPlugins} from 'app/server/lib/PluginEndpoint'
 import {PluginManager} from 'app/server/lib/PluginManager';
 import * as ProcessMonitor from 'app/server/lib/ProcessMonitor';
 import {adaptServerUrl, getOrgUrl, getOriginUrl, getScope, isDefaultUser, optStringParam,
-        RequestWithGristInfo, sendOkReply, stringParam, TEST_HTTPS_OFFSET,
+        RequestWithGristInfo, sendOkReply, stringArrayParam, stringParam, TEST_HTTPS_OFFSET,
         trustOrigin} from 'app/server/lib/requestUtils';
 import {ISendAppPageOptions, makeGristConfig, makeMessagePage, makeSendAppPage} from 'app/server/lib/sendAppPage';
 import {getDatabaseUrl, listenPromise} from 'app/server/lib/serverUtils';
@@ -1304,12 +1304,28 @@ export class FlexServer implements GristServer {
     this.app.post('/welcome/info', ...middleware, expressWrap(async (req, resp, next) => {
       const userId = getUserId(req);
       const user = getUser(req);
-      const row = {...req.body, UserID: userId, Name: user.name, Email: user.loginEmail};
+      const useCases = stringArrayParam(req.body.use_cases, 'use_cases');
+      const useOther = stringParam(req.body.use_other, 'use_other');
+      const row = {
+        UserID: userId,
+        Name: user.name,
+        Email: user.loginEmail,
+        use_cases: ['L', ...useCases],
+        use_other: useOther,
+      };
       this._recordNewUserInfo(row)
       .catch(e => {
         // If we failed to record, at least log the data, so we could potentially recover it.
         log.rawWarn(`Failed to record new user info: ${e.message}`, {newUserQuestions: row});
       });
+      this.getTelemetry().logEvent('welcomeQuestionsSubmitted', {
+        full: {
+          userId,
+          useCases,
+          useOther,
+        },
+      })
+      .catch(e => log.error('failed to log telemetry event welcomeQuestionsSubmitted', e));
 
       resp.status(200).send();
     }), jsonErrorHandler); // Add a final error handler that reports errors as JSON.

app/server/lib/requestUtils.ts

@@ -282,6 +282,17 @@ export function stringParam(p: any, name: string, options: StringParamOptions =
   return p;
 }
 
+export function stringArrayParam(p: any, name: string): string[] {
+  if (!Array.isArray(p)) {
+    throw new ApiError(`${name} parameter should be an array: ${p}`, 400);
+  }
+  if (p.some(el => typeof el !== 'string')) {
+    throw new ApiError(`${name} parameter should be a string array: ${p}`, 400);
+  }
+
+  return p;
+}
+
 export function optIntegerParam(p: any, name: string): number|undefined {
   if (p === undefined) { return p; }