feat: add validation for null values in bookingFieldsResponses (calcom#25272)

* feat: add validation for null values in bookingFieldsResponses

- Add test case to verify 400 error when bookingFieldsResponses contains null values
- Create ValidateBookingFieldsResponses decorator to reject null values in booking field responses
- Apply validator to CreateBookingInput_2024_08_13.bookingFieldsResponses property
- Ensure all booking field response values are non-null strings

* feat: transform null values to empty strings in bookingFieldsResponses

- Remove ValidateBookingFieldsResponses validator that rejected null values
- Add Transform decorator to convert null values to empty strings in bookingFieldsResponses
- Update test to verify null values are transformed to empty strings instead of returning 400 error

* remove extra spaces

* test: add rescheduleReason null value test case

---------

Co-authored-by: Morgan <33722304+ThyMinimalDev@users.noreply.github.com>

Author: ibex088

apps/api/v2/src/ee/bookings/2024-08-13/controllers/e2e/booking-fields.e2e-spec.ts

@@ -20,11 +20,7 @@ import { randomString } from "test/utils/randomString";
 import { withApiAuth } from "test/utils/withApiAuth";
 
 import { CAL_API_VERSION_HEADER, SUCCESS_STATUS, VERSION_2024_08_13 } from "@calcom/platform-constants";
-import {
-  CreateBookingInput_2024_08_13,
-  GetBookingOutput_2024_08_13,
-  GetSeatedBookingOutput_2024_08_13,
-} from "@calcom/platform-types";
+import { CreateBookingInput_2024_08_13, GetBookingOutput_2024_08_13, GetSeatedBookingOutput_2024_08_13 } from "@calcom/platform-types";
 import { BookingOutput_2024_08_13 } from "@calcom/platform-types";
 import type { Booking, PlatformOAuthClient, Team, User, EventType } from "@calcom/prisma/client";
 
@@ -854,7 +850,7 @@ describe("Bookings Endpoints 2024-08-13", () => {
 
     describe("Booking Field Type Validation", () => {
       const basePayload = {
-        start: "2025-06-19T11:00:00.000Z",
+        start: new Date(Date.UTC(2030, 5, 19, 11, 0, 0)).toISOString(),
         attendee: {
           name: "Charlie TypeTest",
           email: "charlie.typetest@example.com",
@@ -1162,6 +1158,31 @@ describe("Bookings Endpoints 2024-08-13", () => {
           `One or more invalid options for booking field '${fieldName}'. Allowed options are: blue, red.`
         );
       });
+
+      it("should transform null values to empty strings in bookingFieldsResponses", async () => {
+        const payload = {
+          ...basePayload,
+          eventTypeId: eventTypeWithBookingFields.id,
+          bookingFieldsResponses: {
+            "favorite-movie": "The Matrix",
+            rescheduleReason: null,
+            notes: null,
+          },
+        };
+        const response = await request(app.getHttpServer())
+          .post(`/v2/bookings`)
+          .send(payload)
+          .set(CAL_API_VERSION_HEADER, VERSION_2024_08_13);
+        expect(response.status).toBe(201);
+        expect(response.body.status).toEqual(SUCCESS_STATUS);
+
+        if (responseDataIsBooking(response.body.data)) {
+          const data: BookingOutput_2024_08_13 = response.body.data;
+          expect(data.bookingFieldsResponses.notes).toBe("");
+          expect(data.bookingFieldsResponses.rescheduleReason).toBe("");
+          expect(data.bookingFieldsResponses["favorite-movie"]).toBe("The Matrix");
+        }
+      });
     });
 
     afterAll(async () => {
@@ -1176,4 +1197,4 @@ describe("Bookings Endpoints 2024-08-13", () => {
   function responseDataIsBooking(data: any): data is BookingOutput_2024_08_13 {
     return !Array.isArray(data) && typeof data === "object" && data && "id" in data;
   }
-});
+});

packages/platform/types/bookings/2024-08-13/inputs/create-booking.input.ts

@@ -1,5 +1,5 @@
 import { ApiExtraModels, ApiProperty, ApiPropertyOptional, getSchemaPath } from "@nestjs/swagger";
-import { Type } from "class-transformer";
+import { Transform, Type } from "class-transformer";
 import type { ValidationArguments, ValidationOptions } from "class-validator";
 import {
   IsInt,
@@ -239,6 +239,14 @@ export class CreateBookingInput_2024_08_13 {
   })
   @IsObject()
   @IsOptional()
+  @Transform(({ value }) => {
+    if (!value || typeof value !== "object") return value;
+    const transformed: Record<string, unknown> = {};
+    for (const [key, val] of Object.entries(value)) {
+      transformed[key] = val === null ? "" : val;
+    }
+    return transformed;
+  })
   bookingFieldsResponses?: Record<string, unknown>;
 
   @ApiPropertyOptional({