chore(deps-dev): bump @types/busboy from 0.3.0 to 0.3.1 (#2979)

* chore(deps-dev): bump @types/busboy from 0.3.0 to 0.3.1

Bumps [@types/busboy](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/busboy) from 0.3.0 to 0.3.1.
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/busboy)

---
updated-dependencies:
- dependency-name: "@types/busboy"
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

* fix: update busboy namespace back to lowercased variant

* feat: add typeguard for busboy headers

* test(email-submission): add test for typeguard in busboy headers

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Kar Rui Lau <[email protected]>

package.json

@@ -165,7 +165,7 @@
     "@opengovsg/mockpass": "^2.7.9",
     "@types/bcrypt": "^5.0.0",
     "@types/bluebird": "^3.5.36",
-    "@types/busboy": "^0.3.0",
+    "@types/busboy": "^0.3.1",
     "@types/compression": "^1.7.2",
     "@types/connect-datadog": "0.0.6",
     "@types/convict": "^6.1.1",

src/app/modules/submission/email-submission/__tests__/email-submission.receiver.spec.ts

@@ -2,7 +2,7 @@ import Busboy from 'busboy'
 import FormData from 'form-data'
 import { createReadStream, readFileSync } from 'fs'
 import { IncomingHttpHeaders } from 'http'
-import { pick } from 'lodash'
+import { omit, pick } from 'lodash'
 import { mocked } from 'ts-jest/utils'
 
 import {
@@ -22,12 +22,15 @@ jest.mock('busboy')
 const MockBusboy = mocked(Busboy, true)
 const RealBusboy = jest.requireActual('busboy') as typeof Busboy
 
-const MOCK_HEADERS = { key: 'value' }
+const MOCK_HEADERS: IncomingHttpHeaders = {
+  'content-type': 'anything',
+  key: 'value',
+}
 
 const MOCK_BUSBOY_ON = jest.fn().mockReturnThis()
 const MOCK_BUSBOY = {
   on: MOCK_BUSBOY_ON,
-} as unknown as busboy.Busboy
+} as unknown as Busboy.Busboy
 
 const VALID_FILE_PATH = 'tests/unit/backend/resources/'
 const VALID_FILENAME_1 = 'valid.txt'
@@ -40,13 +43,15 @@ const VALID_FILE_CONTENT_2 = readFileSync(
 )
 
 describe('email-submission.receiver', () => {
+  beforeEach(() => {
+    MockBusboy.mockReset()
+  })
   describe('createMultipartReceiver', () => {
     it('should call Busboy constructor with the correct params', () => {
       MockBusboy.mockReturnValueOnce(MOCK_BUSBOY)
 
-      const result = EmailSubmissionReceiver.createMultipartReceiver(
-        MOCK_HEADERS as IncomingHttpHeaders,
-      )
+      const result =
+        EmailSubmissionReceiver.createMultipartReceiver(MOCK_HEADERS)
 
       expect(MockBusboy).toHaveBeenCalledWith({
         headers: MOCK_HEADERS,
@@ -58,14 +63,25 @@ describe('email-submission.receiver', () => {
       expect(result._unsafeUnwrap()).toEqual(MOCK_BUSBOY)
     })
 
+    it('should return error headers are missing content-type key-value', () => {
+      const result = EmailSubmissionReceiver.createMultipartReceiver(
+        omit(MOCK_HEADERS, 'content-type'),
+      )
+
+      // Should have failed type guard and not have been called.
+      expect(MockBusboy).not.toHaveBeenCalled()
+      expect(result._unsafeUnwrapErr()).toEqual(
+        new InitialiseMultipartReceiverError(),
+      )
+    })
+
     it('should return error when busboy constructor errors', () => {
       MockBusboy.mockImplementationOnce(() => {
         throw new Error()
       })
 
-      const result = EmailSubmissionReceiver.createMultipartReceiver(
-        MOCK_HEADERS as IncomingHttpHeaders,
-      )
+      const result =
+        EmailSubmissionReceiver.createMultipartReceiver(MOCK_HEADERS)
 
       expect(MockBusboy).toHaveBeenCalledWith({
         headers: MOCK_HEADERS,

src/app/modules/submission/email-submission/email-submission.receiver.ts

@@ -1,4 +1,4 @@
-import Busboy from 'busboy'
+import Busboy, { BusboyHeaders } from 'busboy'
 import { IncomingHttpHeaders } from 'http'
 import { err, ok, Result, ResultAsync } from 'neverthrow'
 
@@ -20,13 +20,30 @@ import {
 
 const logger = createLoggerWithLabel(module)
 
+const isBusboyHeaders = (
+  headers: IncomingHttpHeaders,
+): headers is BusboyHeaders => {
+  return !!headers['content-type']
+}
+
 /**
  * Initialises a Busboy object to receive the submission stream
  * @param headers HTTP request headers
  */
 export const createMultipartReceiver = (
   headers: IncomingHttpHeaders,
 ): Result<Busboy.Busboy, InitialiseMultipartReceiverError> => {
+  if (!isBusboyHeaders(headers)) {
+    logger.error({
+      message: "Busboy cannot be init due to missing headers['content-type']",
+      meta: {
+        action: 'createMultipartReceiver',
+        headers,
+      },
+    })
+    return err(new InitialiseMultipartReceiverError())
+  }
+
   try {
     const busboy = new Busboy({
       headers,