From 4c05b2562447fb192d134b2eba9ed0867ddf6771 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cl=C3=A9ment=20Escolano?= <clement.escolano@icloud.com>
Date: Fri, 27 Sep 2019 11:53:35 +0200
Subject: [PATCH 1/3] Refactor headers management for fetchJson

---
 packages/ra-core/src/util/fetch.ts | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/packages/ra-core/src/util/fetch.ts b/packages/ra-core/src/util/fetch.ts
index 9db09fd2bdd..494256fa12b 100644
--- a/packages/ra-core/src/util/fetch.ts
+++ b/packages/ra-core/src/util/fetch.ts
@@ -8,7 +8,7 @@ interface Options extends RequestInit {
     };
 }
 
-export const fetchJson = (url, options: Options = {}) => {
+export const createHeadersFromOptions = (options: Options): Headers => {
     const requestHeaders = (options.headers ||
         new Headers({
             Accept: 'application/json',
@@ -23,6 +23,12 @@ export const fetchJson = (url, options: Options = {}) => {
         requestHeaders.set('Authorization', options.user.token);
     }
 
+    return requestHeaders;
+};
+
+export const fetchJson = (url, options: Options = {}) => {
+    const requestHeaders = createHeadersFromOptions(options);
+
     return fetch(url, { ...options, headers: requestHeaders })
         .then(response =>
             response.text().then(text => ({

From 1284bab9602f86aa0d2328f822a6d204035e5ec7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cl=C3=A9ment=20Escolano?= <clement.escolano@icloud.com>
Date: Fri, 27 Sep 2019 11:59:25 +0200
Subject: [PATCH 2/3] Add Content-Type header only for non GET requests.

---
 packages/ra-core/src/util/fetch.spec.ts | 32 ++++++++++++++++++++++++-
 packages/ra-core/src/util/fetch.ts      |  1 +
 2 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/packages/ra-core/src/util/fetch.spec.ts b/packages/ra-core/src/util/fetch.spec.ts
index 2f7b7f08eae..b8bf9bc4c93 100644
--- a/packages/ra-core/src/util/fetch.spec.ts
+++ b/packages/ra-core/src/util/fetch.spec.ts
@@ -1,5 +1,9 @@
 import assert from 'assert';
-import { queryParameters, flattenObject } from './fetch';
+import {
+    createHeadersFromOptions,
+    queryParameters,
+    flattenObject,
+} from './fetch';
 
 describe('queryParameters', () => {
     it('should generate a query parameter', () => {
@@ -57,3 +61,29 @@ describe('flattenObject', () => {
         assert.deepEqual(flattenObject(input), expected);
     });
 });
+
+describe('createHeadersFromOptions', () => {
+    it('should add a Content-Type header for POST requests', () => {
+        const options = {
+            method: 'POST',
+        };
+
+        const headers = createHeadersFromOptions(options);
+        assert.strictEqual(headers.get('Content-Type'), 'application/json');
+    });
+
+    it('should not add a Content-Type header for GET requests', () => {
+        const optionsWithoutMethod = {};
+        const optionsWithMethod = {
+            method: 'GET',
+        };
+
+        const headersWithMethod = createHeadersFromOptions(optionsWithMethod);
+        assert.strictEqual(headersWithMethod.get('Content-Type'), null);
+
+        const headersWithoutMethod = createHeadersFromOptions(
+            optionsWithoutMethod
+        );
+        assert.strictEqual(headersWithoutMethod.get('Content-Type'), null);
+    });
+});
diff --git a/packages/ra-core/src/util/fetch.ts b/packages/ra-core/src/util/fetch.ts
index 494256fa12b..d656529674e 100644
--- a/packages/ra-core/src/util/fetch.ts
+++ b/packages/ra-core/src/util/fetch.ts
@@ -15,6 +15,7 @@ export const createHeadersFromOptions = (options: Options): Headers => {
         })) as Headers;
     if (
         !requestHeaders.has('Content-Type') &&
+        !(options && (!options.method || options.method === 'GET')) &&
         !(options && options.body && options.body instanceof FormData)
     ) {
         requestHeaders.set('Content-Type', 'application/json');

From 7bcdd9e97182d3c822218f9bd69b624bb76a3a15 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cl=C3=A9ment=20Escolano?= <clement.escolano@icloud.com>
Date: Fri, 27 Sep 2019 13:48:41 +0200
Subject: [PATCH 3/3] Mock fetch Headers to make tests work

---
 package.json  |  3 ++-
 test-setup.js | 10 ++++++++++
 yarn.lock     |  2 +-
 3 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/package.json b/package.json
index 8165fbf520a..e5ad1b27794 100644
--- a/package.json
+++ b/package.json
@@ -65,7 +65,8 @@
         "prettier": "~1.17.1",
         "raf": "~3.4.0",
         "ts-jest": "^23.10.5",
-        "wait-on": "^2.1.0"
+        "wait-on": "^2.1.0",
+        "whatwg-fetch": "^3.0.0"
     },
     "workspaces": [
         "packages/*",
diff --git a/test-setup.js b/test-setup.js
index a552cd44b6d..75c36b2d37e 100644
--- a/test-setup.js
+++ b/test-setup.js
@@ -45,3 +45,13 @@ jest.mock('popper.js', () => {
     ];
     return Popper;
 });
+
+/**
+ * Mock fetch objects Response, Request and Headers
+ */
+
+const { Response, Headers, Request } = require('whatwg-fetch');
+
+global.Response = Response;
+global.Headers = Headers;
+global.Request = Request;
diff --git a/yarn.lock b/yarn.lock
index 0d512c1f14d..357c98f456c 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -16035,7 +16035,7 @@ whatwg-encoding@^1.0.3, whatwg-encoding@^1.0.5:
   dependencies:
     iconv-lite "0.4.24"
 
-whatwg-fetch@3.0.0:
+whatwg-fetch@3.0.0, whatwg-fetch@^3.0.0:
   version "3.0.0"
   resolved "https://registry.yarnpkg.com/whatwg-fetch/-/whatwg-fetch-3.0.0.tgz#fc804e458cc460009b1a2b966bc8817d2578aefb"
   integrity sha512-9GSJUgz1D4MfyKU7KRqwOjXCXTqWdFNvEr7eUBYchQiVc744mqK/MzXPNR2WsPkmkOa4ywfg8C2n8h+13Bey1Q==