fix: custom base path not working

packages/better-auth/src/api/index.ts

@@ -162,6 +162,7 @@ export const router = <C extends AuthContext, Option extends BetterAuthOptions>(
 ) => {
 	const { api, middlewares } = getEndpoints(ctx, options);
 	const basePath = new URL(ctx.baseURL).pathname;
+	console.log({ basePath });
 
 	return createRouter(api, {
 		extraContext: ctx,

packages/better-auth/src/auth.ts

@@ -3,6 +3,7 @@ import { getEndpoints, router } from "./api";
 import { init } from "./init";
 import type { BetterAuthOptions } from "./types/options";
 import type { InferPluginTypes, InferSession, InferUser } from "./types";
+import { getBaseURL } from "./utils/base-url";
 
 type InferAPI<API> = Omit<
 	API,
@@ -19,21 +20,15 @@ export const betterAuth = <O extends BetterAuthOptions>(options: O) => {
 	const authContext = init(options);
 	const { api } = getEndpoints(authContext, options);
 	type API = typeof api;
-	type X = API extends { [key in infer K]: Endpoint }
-		? K extends string
-			? API[K]["options"]["metadata"] extends { isAction: false }
-				? K
-				: never
-			: never
-		: never;
 
 	return {
 		handler: async (request: Request) => {
 			const ctx = await authContext;
-			const basePath = ctx.options.basePath;
+			const basePath = ctx.options.basePath || "/api/auth";
 			const url = new URL(request.url);
 			if (!ctx.options.baseURL) {
-				const baseURL = `${url.origin}/api/auth`;
+				const baseURL =
+					getBaseURL(undefined, basePath) || `${url.origin}${basePath}`;
 				ctx.options.baseURL = baseURL;
 				ctx.baseURL = baseURL;
 			}

packages/better-auth/src/client/config.ts

@@ -8,6 +8,7 @@ export const getClientConfig = <O extends ClientOptions>(options?: O) => {
 	const $fetch = createFetch({
 		baseURL: getBaseURL(options?.fetchOptions?.baseURL || options?.baseURL),
 		credentials: "include",
+		method: "GET",
 		...options?.fetchOptions,
 		plugins: [
 			csrfPlugin,

packages/better-auth/src/init.test.ts

@@ -1,6 +1,8 @@
 import { describe, expect, it } from "vitest";
 import { init } from "./init";
 import Database from "better-sqlite3";
+import { betterAuth } from "./auth";
+import { createAuthClient } from "./client";
 
 describe("init", async () => {
 	const database = new Database(":memory:");
@@ -44,4 +46,32 @@ describe("init", async () => {
 		});
 		expect(res).toMatchObject(changedCtx);
 	});
+
+	it("should work with custom path", async () => {
+		const customPath = "/custom-path";
+		const ctx = await init({
+			database,
+			basePath: customPath,
+			baseURL: "http://localhost:3000",
+		});
+		expect(ctx.baseURL).toBe(`http://localhost:3000${customPath}`);
+
+		const res = betterAuth({
+			database,
+			basePath: customPath,
+		});
+
+		const client = createAuthClient({
+			baseURL: `http://localhost:3000/custom-path`,
+			fetchOptions: {
+				customFetchImpl: async (url, init) => {
+					return res.handler(new Request(url, init));
+				},
+			},
+		});
+		const ok = await client.$fetch("/ok");
+		expect(ok.data).toMatchObject({
+			ok: true,
+		});
+	});
 });