fix: clone body correctly

src/index.ts

@@ -1,4 +1,4 @@
-import { getMainProvider, parseProviders, verify } from "./utils";
+import { cloneFormData, getMainProvider, parseBody, parseProviders, verify } from "./utils";
 
 export default {
 	async fetch(request: Request, env: Env, _: ExecutionContext): Promise<Response> {
@@ -17,14 +17,14 @@ export default {
 
 		providers.sort((a, _) => (a.name === mainProvider?.name ? 1 : -1));
 
-		const body = request.body !== null ? request.body : null;
+		const body = request.body ? await parseBody(request) : null;
 
 		let res: Response;
 		for (const provider of providers) {
 			const url = new URL(provider.url);
 			url.pathname += baseUrl.pathname;
 
-			if (request.body !== null) {
+			if (body !== null) {
 				// @ts-expect-error expected
 				res = await fetch(url.toString(), {
 					method: request.method,
@@ -32,7 +32,7 @@ export default {
 						...request.headers,
 						authorization: `Bearer ${btoa(provider.token)}`,
 					},
-					body: body,
+					body: body(),
 				});
 			} else {
 				// @ts-expect-error expected

src/utils.ts

@@ -28,3 +28,32 @@ export function parseProviders(providers: string): Provider[] {
 export function getMainProvider(providers: Provider[], main: string): Provider | undefined {
 	return providers.find((provider) => provider.name === main) ?? providers[0];
 }
+
+export async function parseBody(request: Request): Promise<() => BodyInit> {
+	const contentType = request.headers.get("content-type");
+	if (contentType === "multipart/form-data" || contentType === "application/x-www-form-urlencoded") {
+		const data = await request.formData();
+		return () => cloneFormData(data);
+	}
+
+	if (contentType === "application/json") {
+		const data = await request.json();
+		return () => JSON.stringify(data);
+	}
+
+	const text = await request.text();
+	return () => text;
+}
+
+export function cloneFormData(data: FormData) {
+	const form = new FormData();
+	for (const [key, value] of data.entries()) {
+		if (value instanceof File) {
+			form.append(key, value, value.name);
+		} else {
+			form.append(key, value);
+		}
+	}
+
+	return form;
+}