feat: hooks (#916)

docs/components/sidebar-content.tsx

@@ -233,6 +233,26 @@ export const contents: Content[] = [
 					</svg>
 				),
 			},
+			{
+				href: "/docs/concepts/hooks",
+				title: "Hooks",
+				icon: (props?: SVGProps<any>) => (
+					<svg
+						xmlns="http://www.w3.org/2000/svg"
+						width="1.2em"
+						height="1.2em"
+						viewBox="0 0 65 64"
+						fill="currentColor"
+					>
+						<path
+							fill="currentColor"
+							fillRule="evenodd"
+							d="M30.719 27.2c-6.18-3.098-8.44-7.209-6.946-12.241c1.316-4.435 5.752-7.337 10.27-6.655c2.253.34 4.235 1.263 5.78 3.023c2.337 2.667 2.865 5.78 2.151 9.246l2.135.579l3.201.868c2.273-6.234-.393-13.518-6.214-17.258c-6.061-3.893-13.914-3.071-19.062 2c-2.687 2.649-4.158 5.88-4.5 9.62c-.483 5.29 1.703 9.558 5.375 13.21l-5.84 9.793q-.283.02-.502.033c-.269.016-.48.029-.688.058c-3.839.544-6.54 3.958-5.895 7.44c.73 3.933 4.309 6.348 7.983 5.385c3.896-1.02 5.97-4.78 4.5-8.644c-.532-1.398-.203-2.294.463-3.394c1.877-3.101 3.727-6.219 5.61-9.394zm13.222 4.686l-5.647-9.96q.14-.349.272-.665v-.001c.185-.448.354-.858.495-1.277c.747-2.21.296-4.228-1.122-6.02c-1.736-2.194-4.764-2.991-7.345-2.004c-2.605.997-4.272 3.554-4.158 6.383c.115 2.86 2.034 5.414 5.008 5.929c1.78.308 2.652 1.154 3.442 2.61c1.68 3.1 3.42 6.165 5.162 9.233v.001q1.033 1.817 2.061 3.64c5.832-3.888 10.657-3.764 14.26.285c3.12 3.51 3.186 8.854.153 12.438c-3.557 4.201-8.348 4.368-13.826.82l-4.352 3.642c5.546 5.536 13.463 6.272 19.723 1.963c6.099-4.199 8.222-12.258 5.116-19.063c-2.57-5.633-9.737-10.895-19.242-7.954m-12.623 16.99H42.76q.238.321.455.63c.303.428.592.834.928 1.195c2.424 2.592 6.516 2.72 9.106.315c2.685-2.492 2.807-6.68.27-9.281c-2.483-2.547-6.725-2.79-9.03-.094c-1.4 1.639-2.835 1.831-4.694 1.802c-3.397-.052-6.795-.042-10.193-.032q-2.045.007-4.088.008c.309 6.695-2.222 10.867-7.242 11.858c-4.916.97-9.443-1.538-11.037-6.114c-1.81-5.2.428-9.359 6.898-12.66c-.487-1.763-.98-3.548-1.466-5.315C5.617 32.724.327 39.565.872 47.26c.483 6.793 5.963 12.827 12.665 13.907c3.64.588 7.06-.022 10.233-1.822c4.082-2.316 6.451-5.958 7.548-10.47"
+							clipRule="evenodd"
+						></path>
+					</svg>
+				),
+			},
 			{
 				href: "/docs/concepts/plugins",
 				title: "Plugins",

docs/content/docs/concepts/hooks.mdx

@@ -0,0 +1,161 @@
+---
+title: Hooks
+description: Better Auth Hooks let you customize BetterAuth's behavior
+---
+
+Hooks in Better Auth let you "hook into" the lifecycle and execute custom logic. They provide a way to customize Better Auth's behavior without writing a full plugin.
+
+## Before Hooks
+
+**Before hooks** run *before* an endpoint is executed. Use them to modify requests, pre validate data, or return early.
+
+### Example: Enforce Email Domain Restriction
+
+This hook ensures that users can only sign up if their email ends with `@example.com`:
+
+```ts title="auth.ts"
+import { betterAuth } from "better-auth";
+import { createAuthMiddleware } from "better-auth/api";
+
+export const auth = betterAuth({
+    hooks: {
+        before: createAuthMiddleware(async (ctx) => {
+            if (ctx.path !== "/sign-up/email") {
+                return;
+            }
+            if (!ctx.body?.email.endsWith("@example.com")) {
+                throw new APIError("BAD_REQUEST", {
+                    message: "Email must end with @example.com",
+                });
+            }
+        }),
+    },
+});
+```
+
+### Example: Modify Request Context
+
+To adjust the request context before proceeding:
+
+```ts
+import { betterAuth } from "better-auth";
+
+export const auth = betterAuth({
+    hooks: {
+        before: createAuthMiddleware(async (ctx) => {
+            if (ctx.path === "/sign-up/email") {
+                return {
+                    ...ctx,
+                    body: {
+                        ...ctx.body,
+                        name: "John Doe",
+                    },
+                };
+            }
+        }),
+    },
+});
+```
+
+## After Hooks
+
+**After hooks** run *after* an endpoint is executed. Use them to modify responses.
+
+### Example: Add a Custom Header
+
+This hook adds a custom header to the response:
+
+```ts
+import { betterAuth } from "better-auth";
+
+export const auth = betterAuth({
+    hooks: {
+        after: createAuthMiddleware(async (ctx) => {
+            ctx.response.headers.set("X-Custom-Header", "Hello World");
+            return {
+                responseHeader: ctx.responseHeader // return the updated response headers
+            }
+        }),
+    },
+});
+```
+
+## Context Object
+
+The `ctx` object provides:
+
+- **Path:** `ctx.path` to get the current endpoint path.
+- **Body:** `ctx.body` for parsed request body (available for POST requests).
+- **Headers:** `ctx.headers` to access request headers.
+- **Request:** `ctx.request` to access the request object (may not exist in server-only endpoints).
+- **Query Parameters:** `ctx.query` to access query parameters.
+
+and more.
+
+### JSON Responses
+
+Use `ctx.json` to send JSON responses:
+
+```ts
+const hook = createAuthMiddleware(async (ctx) => {
+    return ctx.json({
+        message: "Hello World",
+    });
+});
+```
+
+### Redirects
+
+Use `ctx.redirect` to redirect users:
+
+```ts
+const hook = createAuthMiddleware(async (ctx) => {
+    throw ctx.redirect("/sign-up/name");
+});
+```
+
+### Cookies
+
+- Set cookies: `ctx.setCookies` or `ctx.setSignedCookie`.
+- Get cookies: `ctx.getCookies` or `ctx.getSignedCookies`.
+
+Example:
+
+```ts
+const hook = createAuthMiddleware(async (ctx) => {
+    ctx.setCookies("my-cookie", "value");
+    await ctx.setSignedCookie("my-signed-cookie", "value", ctx.context.secret, {
+        maxAge: 1000,
+    });
+
+    const cookie = ctx.getCookies("my-cookie");
+    const signedCookie = await ctx.getSignedCookies("my-signed-cookie");
+});
+```
+
+### Predefined Auth Cookies
+
+Access BetterAuth’s predefined cookie properties:
+
+```ts
+const hook = createAuthMiddleware(async (ctx) => {
+    const cookieName = ctx.context.authCookies.sessionToken.name;
+});
+```
+
+### Errors
+
+Throw errors with `APIError` for a specific status code and message:
+
+```ts
+const hook = createAuthMiddleware(async (ctx) => {
+    throw new APIError("BAD_REQUEST", {
+        message: "Invalid request",
+    });
+});
+```
+
+## Reusable Hooks
+
+If you need to reuse a hook across multiple endpoints, consider creating a plugin. Learn more in the [Plugins Documentation](/docs/concepts/plugins).
+

packages/better-auth/src/api/call.test.ts

@@ -10,13 +10,14 @@ import { init } from "../init";
 import type { BetterAuthOptions, BetterAuthPlugin } from "../types";
 import { z } from "zod";
 import { createAuthClient } from "../client";
-import { convertSetCookieToCookie } from "../test-utils/headers";
 
 describe("call", async () => {
 	const q = z.optional(
 		z.object({
 			testBeforeHook: z.string().optional(),
+			testBeforeGlobal: z.string().optional(),
 			testAfterHook: z.string().optional(),
+			testAfterGlobal: z.string().optional(),
 			testContext: z.string().optional(),
 			message: z.string().optional(),
 		}),
@@ -180,6 +181,28 @@ describe("call", async () => {
 		emailAndPassword: {
 			enabled: true,
 		},
+		hooks: {
+			before: createAuthMiddleware(async (ctx) => {
+				if (ctx.path === "/sign-up/email") {
+					return {
+						context: {
+							body: {
+								...ctx.body,
+								email: "changed@email.com",
+							},
+						},
+					};
+				}
+				if (ctx.query?.testBeforeGlobal) {
+					return ctx.json({ before: "global" });
+				}
+			}),
+			after: createAuthMiddleware(async (ctx) => {
+				if (ctx.query?.testAfterGlobal) {
+					return ctx.json({ after: "global" });
+				}
+			}),
+		},
 	} satisfies BetterAuthOptions;
 	const authContext = init(options);
 	const { api } = getEndpoints(authContext, options);
@@ -343,6 +366,39 @@ describe("call", async () => {
 			});
 	});
 
+	it("should intercept on global before hook", async () => {
+		const response = await api.test({
+			query: {
+				testBeforeGlobal: "true",
+			},
+		});
+		expect(response).toMatchObject({
+			before: "global",
+		});
+	});
+
+	it("should intercept on global after hook", async () => {
+		const response = await api.test({
+			query: {
+				testAfterGlobal: "true",
+			},
+		});
+		expect(response).toMatchObject({
+			after: "global",
+		});
+	});
+
+	it("global before hook should change the context", async (ctx) => {
+		const response = await api.signUpEmail({
+			body: {
+				email: "my-email@test.com",
+				password: "password",
+				name: "test",
+			},
+		});
+		expect(response.email).toBe("changed@email.com");
+	});
+
 	it("should fetch using a client", async () => {
 		const response = await client.$fetch("/test");
 		expect(response.data).toMatchObject({

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

@@ -195,14 +195,43 @@ export function getEndpoints<
 			};
 
 			const plugins = options.plugins || [];
-			for (const plugin of plugins) {
-				const beforeHooks = plugin.hooks?.before ?? [];
+			const beforeHooks = plugins
+				.map((plugin) => {
+					if (plugin.hooks?.before) {
+						return plugin.hooks.before;
+					}
+				})
+				.filter((plugin) => plugin !== undefined)
+				.flat();
+			const afterHooks = plugins
+				.map((plugin) => {
+					if (plugin.hooks?.after) {
+						return plugin.hooks.after;
+					}
+				})
+				.filter((plugin) => plugin !== undefined)
+				.flat();
+			if (options.hooks?.before) {
+				beforeHooks.push({
+					matcher: () => true,
+					handler: options.hooks.before,
+				});
+			}
+			if (options.hooks?.after) {
+				afterHooks.push({
+					matcher: () => true,
+					handler: options.hooks.after,
+				});
+			}
 			for (const hook of beforeHooks) {
 				if (!hook.matcher(internalContext)) continue;
 				const hookRes = await hook.handler(internalContext);
 				if (hookRes && "context" in hookRes) {
 					// modify the context with the response from the hook
-						internalContext = defu(internalContext, hookRes.context);
+					internalContext = {
+						...internalContext,
+						...hookRes.context,
+					};
 					continue;
 				}
 
@@ -211,7 +240,6 @@ export function getEndpoints<
 					return hookRes;
 				}
 			}
-			}
 
 			let endpointRes: any;
 			try {
@@ -225,25 +253,16 @@ export function getEndpoints<
 					internalContext.context.newSession = newSession;
 				}
 				if (e instanceof APIError) {
-					const afterPlugins = options.plugins
-						?.map((plugin) => {
-							if (plugin.hooks?.after) {
-								return plugin.hooks.after;
-							}
-						})
-						.filter((plugin) => plugin !== undefined)
-						.flat();
-
 					/**
 					 * If there are no after plugins, we can directly throw the error
 					 */
-					if (!afterPlugins?.length) {
+					if (!afterHooks?.length) {
 						e.headers = endpoint.headers;
 						throw e;
 					}
 					internalContext.context.returned = e;
 					internalContext.context.returned.headers = endpoint.headers;
-					for (const hook of afterPlugins || []) {
+					for (const hook of afterHooks || []) {
 						const match = hook.matcher(internalContext);
 						if (match) {
 							try {
@@ -272,9 +291,7 @@ export function getEndpoints<
 			}
 			internalContext.context.returned = endpointRes;
 			internalContext.responseHeader = endpoint.headers;
-			for (const plugin of options.plugins || []) {
-				if (plugin.hooks?.after) {
-					for (const hook of plugin.hooks.after) {
+			for (const hook of afterHooks) {
 				const match = hook.matcher(internalContext);
 				if (match) {
 					try {
@@ -296,8 +313,6 @@ export function getEndpoints<
 					}
 				}
 			}
-				}
-			}
 			const response = internalContext.context.returned;
 			if (response instanceof Response) {
 				endpoint.headers.forEach((value, key) => {

packages/better-auth/src/types/adapter.ts

@@ -1,4 +1,5 @@
-import type { BetterAuthOptions } from ".";
+import type { GenericEndpointContext } from "./context";
+import type { BetterAuthOptions } from "./options";
 
 /**
  * Adapter where clause

packages/better-auth/src/types/options.ts

@@ -1,8 +1,12 @@
 import type { Dialect, Kysely, MysqlPool, PostgresPool } from "kysely";
 import type { Account, Session, User, Verification } from "../db/schema";
-import type { BetterAuthPlugin } from ".";
+import type {
+	BetterAuthPlugin,
+	HookAfterHandler,
+	HookBeforeHandler,
+} from "./plugins";
 import type { SocialProviderList, SocialProviders } from "../social-providers";
-import type { AdapterInstance, SecondaryStorage } from ".";
+import type { AdapterInstance, SecondaryStorage, Where } from "./adapter";
 import type { KyselyDatabaseType } from "../adapters/kysely-adapter/types";
 import type { FieldAttribute } from "../db";
 import type { Models, RateLimit } from "./models";
@@ -586,8 +590,11 @@ export type BetterAuthOptions = {
 	 * operations.
 	 */
 	databaseHooks?: {
+		/**
+		 * User hooks
+		 */
 		user?: {
-			[key in "create" | "update"]?: {
+			create?: {
 				/**
 				 * Hook that is called before a user is created.
 				 * if the hook returns false, the user will not be created.
@@ -605,12 +612,33 @@ export type BetterAuthOptions = {
 				 */
 				after?: (user: User) => Promise<void>;
 			};
-		};
-		session?: {
-			[key in "create" | "update"]?: {
+			update?: {
 				/**
-				 * Hook that is called before a user is created.
-				 * if the hook returns false, the user will not be created.
+				 * Hook that is called before a user is updated.
+				 * if the hook returns false, the user will not be updated.
+				 * If the hook returns an object, it'll be used instead of the original data
+				 */
+				before?: (user: Partial<User>) => Promise<
+					| boolean
+					| void
+					| {
+							data: User & Record<string, any>;
+					  }
+				>;
+				/**
+				 * Hook that is called after a user is updated.
+				 */
+				after?: (user: User) => Promise<void>;
+			};
+		};
+		/**
+		 * Session Hook
+		 */
+		session?: {
+			create?: {
+				/**
+				 * Hook that is called before a session is updated.
+				 * if the hook returns false, the session will not be updated.
 				 * If the hook returns an object, it'll be used instead of the original data
 				 */
 				before?: (session: Session) => Promise<
@@ -621,16 +649,40 @@ export type BetterAuthOptions = {
 					  }
 				>;
 				/**
-				 * Hook that is called after a user is created.
+				 * Hook that is called after a session is updated.
+				 */
+				after?: (session: Session) => Promise<void>;
+			};
+			/**
+			 * Update hook
+			 */
+			update?: {
+				/**
+				 * Hook that is called before a user is updated.
+				 * if the hook returns false, the session will not be updated.
+				 * If the hook returns an object, it'll be used instead of the original data
+				 */
+				before?: (session: Partial<Session>) => Promise<
+					| boolean
+					| void
+					| {
+							data: Session & Record<string, any>;
+					  }
+				>;
+				/**
+				 * Hook that is called after a session is updated.
 				 */
 				after?: (session: Session) => Promise<void>;
 			};
 		};
-		account?: {
-			[key in "create" | "update"]?: {
 		/**
-				 * Hook that is called before a user is created.
-				 * If the hook returns false, the user will not be created.
+		 * Account Hook
+		 */
+		account?: {
+			create?: {
+				/**
+				 * Hook that is called before a account is created.
+				 * If the hook returns false, the account will not be created.
 				 * If the hook returns an object, it'll be used instead of the original data
 				 */
 				before?: (account: Account) => Promise<
@@ -641,16 +693,40 @@ export type BetterAuthOptions = {
 					  }
 				>;
 				/**
-				 * Hook that is called after a user is created.
+				 * Hook that is called after a account is created.
+				 */
+				after?: (account: Account) => Promise<void>;
+			};
+			/**
+			 * Update hook
+			 */
+			update?: {
+				/**
+				 * Hook that is called before a account is update.
+				 * If the hook returns false, the user will not be updated.
+				 * If the hook returns an object, it'll be used instead of the original data
+				 */
+				before?: (account: Partial<Account>) => Promise<
+					| boolean
+					| void
+					| {
+							data: Account & Record<string, any>;
+					  }
+				>;
+				/**
+				 * Hook that is called after a account is updated.
 				 */
 				after?: (account: Account) => Promise<void>;
 			};
 		};
-		verification?: {
-			[key in "create" | "update"]: {
 		/**
-				 * Hook that is called before a user is created.
-				 * if the hook returns false, the user will not be created.
+		 * Verification Hook
+		 */
+		verification?: {
+			create?: {
+				/**
+				 * Hook that is called before a verification is created.
+				 * if the hook returns false, the verification will not be created.
 				 * If the hook returns an object, it'll be used instead of the original data
 				 */
 				before?: (verification: Verification) => Promise<
@@ -661,7 +737,25 @@ export type BetterAuthOptions = {
 					  }
 				>;
 				/**
-				 * Hook that is called after a user is created.
+				 * Hook that is called after a verification is created.
+				 */
+				after?: (verification: Verification) => Promise<void>;
+			};
+			update?: {
+				/**
+				 * Hook that is called before a verification is updated.
+				 * if the hook returns false, the verification will not be updated.
+				 * If the hook returns an object, it'll be used instead of the original data
+				 */
+				before?: (verification: Partial<Verification>) => Promise<
+					| boolean
+					| void
+					| {
+							data: Verification & Record<string, any>;
+					  }
+				>;
+				/**
+				 * Hook that is called after a verification is updated.
 				 */
 				after?: (verification: Verification) => Promise<void>;
 			};
@@ -685,4 +779,17 @@ export type BetterAuthOptions = {
 		 */
 		onError?: (error: unknown, ctx: AuthContext) => void | Promise<void>;
 	};
+	/**
+	 * Hooks
+	 */
+	hooks?: {
+		/**
+		 * Before a request is processed
+		 */
+		before?: HookBeforeHandler;
+		/**
+		 * After a request is processed
+		 */
+		after?: HookAfterHandler;
+	};
 };

packages/better-auth/src/types/plugins.ts

@@ -17,6 +17,32 @@ export type PluginSchema = {
 	};
 };
 
+export type HookBeforeHandler = (context: HookEndpointContext) => Promise<
+	| void
+	| {
+			context?: Partial<HookEndpointContext>;
+	  }
+	| Response
+	| {
+			response: Record<string, any>;
+			body: any;
+			_flag: "json";
+	  }
+>;
+
+export type HookAfterHandler = (context: HookEndpointContext) => Promise<
+	| void
+	| {
+			responseHeader?: Headers;
+	  }
+	| Response
+	| {
+			response: Record<string, any>;
+			body: any;
+			_flag: "json";
+	  }
+>;
+
 export type BetterAuthPlugin = {
 	id: LiteralString;
 	/**
@@ -55,18 +81,7 @@ export type BetterAuthPlugin = {
 	hooks?: {
 		before?: {
 			matcher: (context: HookEndpointContext) => boolean;
-			handler: (context: HookEndpointContext) => Promise<
-				| void
-				| {
-						context?: Partial<HookEndpointContext>;
-				  }
-				| Response
-				| {
-						response: Record<string, any>;
-						body: any;
-						_flag: "json";
-				  }
-			>;
+			handler: HookBeforeHandler;
 		}[];
 		after?: {
 			matcher: (
@@ -75,18 +90,7 @@ export type BetterAuthPlugin = {
 					endpoint: Endpoint;
 				}>,
 			) => boolean;
-			handler: (context: HookEndpointContext) => Promise<
-				| void
-				| {
-						responseHeader?: Headers;
-				  }
-				| Response
-				| {
-						response: Record<string, any>;
-						body: any;
-						_flag: "json";
-				  }
-			>;
+			handler: HookAfterHandler;
 		}[];
 	};
 	/**