| |
| title: use server |
| description: Learn how to use the use server directive to execute code on the server. |
| |
|
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| The `use server` directive designates a function or file to be executed on the **server side**. It can be used at the top of a file to indicate that all functions in the file are server-side, or inline at the top of a function to mark the function as a [Server Function](https://19.react.dev/reference/rsc/server-functions). This is a React feature. |
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| ## Using `use server` at the top of a file |
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| The following example shows a file with a `use server` directive at the top. All functions in the file are executed on the server. |
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| ```tsx filename="app/actions.ts" highlight={1} switcher |
| 'use server' |
| import { db } from '@/lib/db' // Your database client |
|
|
| export async function createUser(data: { name: string; email: string }) { |
| const user = await db.user.create({ data }) |
| return user |
| } |
| ``` |
|
|
| ```jsx filename="app/actions.js" highlight={1} switcher |
| 'use server' |
| import { db } from '@/lib/db' // Your database client |
|
|
| export async function createUser(data) { |
| const user = await db.user.create({ data }) |
| return user |
| } |
| ``` |
|
|
| ### Using Server Functions in a Client Component |
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| To use Server Functions in Client Components you need to create your Server Functions in a dedicated file using the `use server` directive at the top of the file. These Server Functions can then be imported into Client and Server Components and executed. |
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| Assuming you have a `fetchUsers` Server Function in `actions.ts`: |
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|
| ```tsx filename="app/actions.ts" highlight={1} switcher |
| 'use server' |
| import { db } from '@/lib/db' // Your database client |
|
|
| export async function fetchUsers() { |
| const users = await db.user.findMany() |
| return users |
| } |
| ``` |
|
|
| ```jsx filename="app/actions.js" highlight={1} switcher |
| 'use server' |
| import { db } from '@/lib/db' // Your database client |
|
|
| export async function fetchUsers() { |
| const users = await db.user.findMany() |
| return users |
| } |
| ``` |
|
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| Then you can import the `fetchUsers` Server Function into a Client Component and execute it on the client-side. |
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|
| ```tsx filename="app/components/my-button.tsx" highlight={1,2,8} switcher |
| 'use client' |
| import { fetchUsers } from '../actions' |
|
|
| export default function MyButton() { |
| return <button onClick={() => fetchUsers()}>Fetch Users</button> |
| } |
| ``` |
|
|
| ```jsx filename="app/components/my-button.js" highlight={1,2,8} switcher |
| 'use client' |
| import { fetchUsers } from '../actions' |
|
|
| export default function MyButton() { |
| return <button onClick={() => fetchUsers()}>Fetch Users</button> |
| } |
| ``` |
|
|
| ## Using `use server` inline |
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| In the following example, `use server` is used inline at the top of a function to mark it as a [Server Function](https://19.react.dev/reference/rsc/server-functions): |
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| ```tsx filename="app/posts/[id]/page.tsx" switcher highlight={8} |
| import { EditPost } from './edit-post' |
| import { revalidatePath } from 'next/cache' |
|
|
| export default async function PostPage({ params }: { params: { id: string } }) { |
| const post = await getPost(params.id) |
|
|
| async function updatePost(formData: FormData) { |
| 'use server' |
| await savePost(params.id, formData) |
| revalidatePath(`/posts/${params.id}`) |
| } |
|
|
| return <EditPost updatePostAction={updatePost} post={post} /> |
| } |
| ``` |
|
|
| ```jsx filename="app/posts/[id]/page.js" switcher highlight={8} |
| import { EditPost } from './edit-post' |
| import { revalidatePath } from 'next/cache' |
|
|
| export default async function PostPage({ params }) { |
| const post = await getPost(params.id) |
|
|
| async function updatePost(formData) { |
| 'use server' |
| await savePost(params.id, formData) |
| revalidatePath(`/posts/${params.id}`) |
| } |
|
|
| return <EditPost updatePostAction={updatePost} post={post} /> |
| } |
| ``` |
|
|
| ## Security considerations |
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| When using the `use server` directive, it's important to ensure that all server-side logic is secure and that sensitive data remains protected. |
| |
| ### Authentication and authorization |
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| Always authenticate and authorize users before performing sensitive server-side operations. |
| |
| ```tsx filename="app/actions.ts" highlight={1,7,8,9,10} switcher |
| 'use server' |
| |
| import { db } from '@/lib/db' // Your database client |
| import { authenticate } from '@/lib/auth' // Your authentication library |
| |
| export async function createUser( |
| data: { name: string; email: string }, |
| token: string |
| ) { |
| const user = authenticate(token) |
| if (!user) { |
| throw new Error('Unauthorized') |
| } |
| const newUser = await db.user.create({ data }) |
| return newUser |
| } |
| ``` |
| |
| ```jsx filename="app/actions.js" highlight={1,7,8,9,10} switcher |
| 'use server' |
| |
| import { db } from '@/lib/db' // Your database client |
| import { authenticate } from '@/lib/auth' // Your authentication library |
| |
| export async function createUser(data, token) { |
| const user = authenticate(token) |
| if (!user) { |
| throw new Error('Unauthorized') |
| } |
| const newUser = await db.user.create({ data }) |
| return newUser |
| } |
| ``` |
| |
| ## Reference |
| |
| See the [React documentation](https://react.dev/reference/rsc/use-server) for more information on `use server`. |
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