From e3036848d19a48935129aec2fe50003518a3aa53 Mon Sep 17 00:00:00 2001
From: Stefanos Anagnostou <anagstef@users.noreply.github.com>
Date: Wed, 12 Jul 2023 14:13:38 +0300
Subject: [PATCH] fix(backend): Access the correct headers to determine the
 Content-Type returned by the Response (#1469)

---
 .changeset/four-monkeys-smell.md       |  5 +++++
 packages/backend/src/api/request.ts    |  5 +++--
 packages/backend/src/util/mockFetch.ts | 16 +++++++---------
 3 files changed, 15 insertions(+), 11 deletions(-)
 create mode 100644 .changeset/four-monkeys-smell.md

diff --git a/.changeset/four-monkeys-smell.md b/.changeset/four-monkeys-smell.md
new file mode 100644
index 0000000000..5d10311a5f
--- /dev/null
+++ b/.changeset/four-monkeys-smell.md
@@ -0,0 +1,5 @@
+---
+'@clerk/backend': patch
+---
+
+Fix the headers checked to determine the Response Content-Type
diff --git a/packages/backend/src/api/request.ts b/packages/backend/src/api/request.ts
index 9f5b2556d5..130d47c059 100644
--- a/packages/backend/src/api/request.ts
+++ b/packages/backend/src/api/request.ts
@@ -2,7 +2,7 @@ import type { ClerkAPIError, ClerkAPIErrorJSON } from '@clerk/types';
 import deepmerge from 'deepmerge';
 import snakecaseKeys from 'snakecase-keys';
 
-import { API_URL, API_VERSION, USER_AGENT } from '../constants';
+import { API_URL, API_VERSION, constants, USER_AGENT } from '../constants';
 // DO NOT CHANGE: Runtime needs to be imported as a default export so that we can stub its dependencies with Sinon.js
 // For more information refer to https://sinonjs.org/how-to/stub-dependency/
 import runtime from '../runtime';
@@ -128,7 +128,8 @@ export function buildRequest(options: CreateBackendApiOptions) {
       }
 
       // TODO: Parse JSON or Text response based on a response header
-      const isJSONResponse = headers['Content-Type'] === 'application/json';
+      const isJSONResponse =
+        res?.headers && res.headers?.get(constants.Headers.ContentType) === constants.ContentTypes.Json;
       const data = await (isJSONResponse ? res.json() : res.text());
 
       if (!res.ok) {
diff --git a/packages/backend/src/util/mockFetch.ts b/packages/backend/src/util/mockFetch.ts
index 6d49be88de..387c18cbd4 100644
--- a/packages/backend/src/util/mockFetch.ts
+++ b/packages/backend/src/util/mockFetch.ts
@@ -1,11 +1,11 @@
+import { constants } from '../constants';
+
 export function jsonOk(body: unknown, status = 200) {
   // Mock response object that satisfies the window.Response interface
   const mockResponse = {
     ok: true,
     status,
-    headers: {
-      'Content-type': 'application/json',
-    },
+    headers: { get: mockHeadersGet },
     json() {
       return Promise.resolve(body);
     },
@@ -19,9 +19,7 @@ export function jsonNotOk(body: unknown) {
   const mockResponse = {
     ok: false,
     status: 422,
-    headers: {
-      'Content-type': 'application/json',
-    },
+    headers: { get: mockHeadersGet },
     json() {
       return Promise.resolve(body);
     },
@@ -35,9 +33,7 @@ export function jsonError(body: unknown, status = 500) {
   const mockResponse = {
     ok: false,
     status: status,
-    headers: {
-      'Content-type': 'application/json',
-    },
+    headers: { get: mockHeadersGet },
     json() {
       return Promise.resolve(body);
     },
@@ -45,3 +41,5 @@ export function jsonError(body: unknown, status = 500) {
 
   return Promise.resolve(mockResponse);
 }
+
+const mockHeadersGet = (key: string) => (key === constants.Headers.ContentType ? constants.ContentTypes.Json : null);