feat: stealth textfield prefill feature from query parameters

package.json

@@ -120,6 +120,7 @@
     "font-awesome": "4.7.0",
     "fp-ts": "^2.8.3",
     "has-ansi": "^4.0.0",
+    "he": "^1.2.0",
     "helmet": "^4.1.1",
     "http-status-codes": "^2.1.4",
     "intl-tel-input": "~12.1.6",

src/app/controllers/public-forms.server.controller.js

@@ -2,6 +2,7 @@
 
 const mongoose = require('mongoose')
 const { StatusCodes } = require('http-status-codes')
+const querystring = require('querystring')
 
 const { createReqMeta } = require('../utils/request')
 const logger = require('../../config/logger').createLoggerWithLabel(module)
@@ -47,6 +48,10 @@ exports.redirect = async function (req, res) {
   let redirectPath = req.params.state
     ? req.params.Id + '/' + req.params.state
     : req.params.Id
+  const reqQuery = querystring.stringify(req.query)
+  if (reqQuery.length > 0) {
+    redirectPath = redirectPath + '?' + encodeURIComponent(reqQuery)
+  }
   try {
     const metaTags = await fetchMetatags(req)
     return res.render('index', {
@@ -62,8 +67,9 @@ exports.redirect = async function (req, res) {
       },
       error: err,
     })
+    res.redirect('/#!/' + redirectPath)
+    return
   }
-  res.redirect('/#!/' + redirectPath)
 }
 
 /**

src/app/routes/frontend.server.routes.js

@@ -14,7 +14,7 @@ module.exports = function (app) {
     celebrate({
       [Segments.QUERY]: {
         redirectPath: Joi.string()
-          .regex(/^[a-fA-F0-9]{24}(\/(preview|template|use-template))?$/)
+          .regex(/^[a-fA-F0-9]{24}(\/(preview|template|use-template))?/)
           .required(),
       },
     }),

src/public/modules/forms/base/directives/field.client.directive.js

@@ -1,12 +1,19 @@
 'use strict'
 
 const { get } = require('lodash')
+const he = require('he')
+const querystring = require('querystring')
 
 angular
   .module('forms')
-  .directive('fieldDirective', ['FormFields', fieldDirective])
+  .directive('fieldDirective', [
+    'FormFields',
+    '$location',
+    '$sanitize',
+    fieldDirective,
+  ])
 
-function fieldDirective(FormFields) {
+function fieldDirective(FormFields, $location, $sanitize) {
   return {
     restrict: 'E',
     templateUrl:
@@ -23,6 +30,30 @@ function fieldDirective(FormFields) {
       isValidateDate: '<',
     },
     link: function (scope) {
+      // Stealth prefill feature
+      // If a query parameter is provided to a form URL in the form ?<fieldId1>=<value1>&<fieldId2>=<value2>...
+      // And if the fieldIds are valid mongoose object IDs and refer to a short text field,
+      // Then prefill and disable editing the corresponding form field on the frontend
+
+      const decodedUrl = he.decode($location.url()) // tech debt; after redirect, & is encoded as &amp; in the query string
+      const query = decodedUrl.split('?')
+      const queryParams =
+        query.length > 1 ? querystring.parse(query[1]) : undefined
+
+      if (
+        queryParams &&
+        scope.field._id in queryParams &&
+        scope.field.fieldType === 'textfield'
+      ) {
+        const prefillValue = queryParams[scope.field._id]
+        if (typeof prefillValue === 'string') {
+          // Only support unique query params. If query params are duplicated,
+          // none of the duplicated keys will be prefilled
+          scope.field.fieldValue = $sanitize(prefillValue) // $sanitize as a precaution to prevent xss
+          scope.field.disabled = true
+        }
+      }
+
       if ((scope.isadminpreview || scope.isTemplate) && scope.field.myInfo) {
         // Determine whether to disable field in preview
         if (

tests/unit/backend/controllers/public-forms.server.controller.spec.js

@@ -30,6 +30,7 @@ describe('Public-Forms Controller', () => {
       params: {},
       body: {},
       headers: {},
+      url: '',
       ip: '127.0.0.1',
       get: () => '',
     }
@@ -90,6 +91,35 @@ describe('Public-Forms Controller', () => {
       Controller.redirect(req, res)
     })
 
+    it('should redirect to form with correct query params retained', (done) => {
+      req.params = {
+        Id: '321564654f65we4f65e4f5',
+      }
+      req.query = {
+        p1: 'v1-_',
+        p2: 'v2',
+        p3: ['v3', 'v4'],
+      }
+
+      res.redirect = jasmine.createSpy().and.callFake(() => {
+        expect(res.redirect).toHaveBeenCalledWith(
+          jasmine.stringMatching(/\?.*p1%3Dv1-_/),
+        )
+        expect(res.redirect).toHaveBeenCalledWith(
+          jasmine.stringMatching(/\?.*p2%3Dv2/),
+        )
+        expect(res.redirect).toHaveBeenCalledWith(
+          jasmine.stringMatching(/\?.*p3%3Dv3/),
+        )
+        expect(res.redirect).toHaveBeenCalledWith(
+          jasmine.stringMatching(/\?.*p3%3Dv4/),
+        )
+        done()
+      })
+
+      Controller.redirect(req, res)
+    })
+
     it('should render index if getting fetchMetatags succeeds', (done) => {
       req.params = {
         Id: testForm._id,