Delete Content-Type header for multipart requests (#211)

index.js

@@ -46,6 +46,7 @@ for (const property of globalProperties) {
 const isObject = value => value !== null && typeof value === 'object';
 const supportsAbortController = typeof globals.AbortController === 'function';
 const supportsStreams = typeof globals.ReadableStream === 'function';
+const supportsFormData = typeof globals.FormData === 'function';
 
 const deepMerge = (...sources) => {
 	let returnValue = {};
@@ -240,6 +241,12 @@ class Ky {
 		if (this._options.searchParams) {
 			const url = new URL(this.request.url);
 			url.search = new URLSearchParams(this._options.searchParams);
+
+			// To provide correct form boundary, Content-Type header should be deleted each time when new Request instantiated from another one
+			if (((supportsFormData && this._options.body instanceof globals.FormData) || this._options.body instanceof URLSearchParams) && !(this._options.headers && this._options.headers['content-type'])) {
+				this.request.headers.delete('content-type');
+			}
+
 			this.request = new globals.Request(new globals.Request(url, this.request), this._options);
 		}
 

test/_require.js

@@ -1,8 +1,10 @@
 import fetch, {Headers, Request, Response} from 'node-fetch';
 import AbortController from 'abort-controller';
+import FormData from 'form-data';
 
 global.fetch = fetch;
 global.Headers = Headers;
 global.Request = Request;
 global.Response = Response;
 global.AbortController = AbortController;
+global.FormData = FormData;

test/browser.js

@@ -173,18 +173,20 @@ test('throws if does not support ReadableStream', withPage, async (t, page) => {
 });
 
 test('FormData with searchParams', withPage, async (t, page) => {
-	t.plan(2);
+	t.plan(3);
 
 	const server = await createTestServer();
 	server.get('/', (request, response) => {
 		response.end();
 	});
 	server.post('/', async (request, response) => {
 		const requestBody = await pBody(request);
+		const contentType = request.headers['content-type'];
+		const boundary = contentType.split('boundary=')[1];
 
+		t.truthy(requestBody.includes(boundary));
 		t.regex(requestBody, /bubblegum pie/);
 		t.deepEqual(request.query, {foo: '1'});
-
 		response.end();
 	});
 
@@ -203,8 +205,7 @@ test('FormData with searchParams', withPage, async (t, page) => {
 	await server.close();
 });
 
-// FIXME: More detailed test that reproduces the bug described in https://github.com/sindresorhus/ky/issues/209
-test.failing('FormData with searchParams ("multipart/form-data" parser)', withPage, async (t, page) => {
+test('FormData with searchParams ("multipart/form-data" parser)', withPage, async (t, page) => {
 	t.plan(3);
 	const server = await createTestServer();
 	server.get('/', (request, response) => {
@@ -213,7 +214,7 @@ test.failing('FormData with searchParams ("multipart/form-data" parser)', withPa
 	server.post('/', async (request, response) => {
 		const [body, error] = await new Promise(resolve => {
 			const busboy = new Busboy({headers: request.headers});
-			busboy.on('error', error => resolve(null, error));
+			busboy.on('error', error => resolve([null, error]));
 			busboy.on('file', async (fieldname, file, filename, encoding, mimetype) => {
 				let fileContent = '';
 				try {
@@ -226,12 +227,14 @@ test.failing('FormData with searchParams ("multipart/form-data" parser)', withPa
 					resolve([null, error_]);
 				}
 			});
+			busboy.on('finish', () => {
+				response.writeHead(303, {Connection: 'close', Location: '/'});
+				response.end();
+			});
 			setTimeout(() => resolve([null, new Error('Timeout')]), 3000);
 			request.pipe(busboy);
 		});
 
-		response.end();
-
 		t.falsy(error);
 		t.deepEqual(request.query, {foo: '1'});
 		t.deepEqual(body, {

test/headers.js

@@ -158,6 +158,37 @@ test('form-data automatic `content-type` header', async t => {
 	t.is(headers['content-type'], `multipart/form-data;boundary=${form.getBoundary()}`);
 });
 
+test('form-data manual `content-type` header with search params', async t => {
+	const server = await createTestServer();
+	server.post('/', echoHeaders);
+
+	const form = new FormData();
+	form.append('a', 'b');
+	const headers = await ky.post(server.url, {
+		searchParams: 'foo=1',
+		headers: {
+			'content-type': 'custom'
+		},
+		body: form
+	}).json();
+
+	t.is(headers['content-type'], 'custom');
+});
+
+test('form-data automatic `content-type` header with search params', async t => {
+	const server = await createTestServer();
+	server.post('/', echoHeaders);
+
+	const form = new FormData();
+	form.append('a', 'b');
+	const headers = await ky.post(server.url, {
+		searchParams: 'foo=1',
+		body: form
+	}).json();
+
+	t.is(headers['content-type'], `multipart/form-data;boundary=${form.getBoundary()}`);
+});
+
 test('form-data sets `content-length` header', async t => {
 	const server = await createTestServer();
 	server.post('/', echoHeaders);