Blitz Adapter for Next.js
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Overview
The @blitzjs/next adapter exposes functions & components specific for
the Next.js framework.
Setup
You can install @blitzjs/next by running the following command:
npm i @blitzjs/next # yarn add @blitzjs/next # pnpm add @blitzjs/next
Next Config
Blitz.js extends the next.config.js file by accepting a blitz
property.
blitz?: {
resolverPath?: ResolverPathOptions;
customServer?: {
hotReload?: boolean;
};
};
Client
Example
Inside src/blitz-client.ts:
import {setupBlitzClient} from "@blitzjs/next"
export const {withBlitz} = setupBlitzClient({
plugins: [],
})
Then inside src/pages/_app.tsx wrap MyApp function with the
withBlitz HOC component.
import {ErrorFallbackProps, ErrorComponent, ErrorBoundary} from "@blitzjs/next"
import {AuthenticationError, AuthorizationError} from "blitz"
import type {AppProps} from "next/app"
import React, {Suspense} from "react"
import {withBlitz} from "src/blitz-client"
function RootErrorFallback({error}: ErrorFallbackProps) {
if (error instanceof AuthenticationError) {
return <div>Error: You are not authenticated</div>
} else if (error instanceof AuthorizationError) {
return (
<ErrorComponent
statusCode={error.statusCode}
title="Sorry, you are not authorized to access this"
/>
)
} else {
return (
<ErrorComponent
statusCode={(error as any)?.statusCode || 400}
title={error.message || error.name}
/>
)
}
}
function MyApp({Component, pageProps}: AppProps) {
return (
<ErrorBoundary FallbackComponent={RootErrorFallback}>
<Component {...pageProps} />
</ErrorBoundary>
)
}
export default withBlitz(MyApp)
API
setupBlitzClient({
plugins: [],
})
Arguments
plugins:An array of Blitz.js plugins- Required
Returns
An object with the withBlitz HOC wrapper
Server
Example
Inside src/blitz-server.ts
import {setupBlitzServer} from "@blitzjs/next"
export const {gSSP, gSP, api} = setupBlitzServer({
plugins: [],
})
API
setupBlitzServer({
plugins: [],
onError?: (err) => void
})
Arguments
plugins:An array of Blitz.js plugins- Required
onError:Catch all errors (Great for services like sentry)
Returns
An object with the gSSP,
gSP & api wrappers.
Custom Server
The Blitz CLI supports running custom Next.js servers. This means you can
compile both javascript & typescript while using the Blitz.js CLI to
inject env variables. By default, the CLI checks for
src/server/index.[ts | js] or src/server.[ts | js]
For more information about custom Next.js servers, check the
official docs
Wrappers
All Next.js wrapper functions are serialized with
superjson. That means you can
use Date, Map, Set & BigInt when returning data. Another thing to
note is that Blitz runs the middlewares from plugins before calling the
Next.js request handler.
Examples
getStaticProps
import {gSP} from "src/blitz-server"
export const getStaticProps = gSP(async ({ctx}) => {
return {
props: {
data: {
userId: ctx?.session.userId,
session: {
id: ctx?.session.userId,
publicData: ctx?.session.$publicData,
},
},
},
}
})
getServerSideProps
import {gSSP} from "src/blitz-server"
export const getServerSideProps = gSSP(async ({ctx}) => {
return {
props: {
userId: ctx?.session.userId,
publicData: ctx?.session.$publicData,
},
}
})
api
import {api} from "src/blitz-server"
export default api(async (req, res, ctx) => {
res.status(200).json({userId: ctx?.session.userId})
})
For more information about Next.js API routes, visit their docs at https://nextjs.org/docs/api-routes/introduction
Concepts
Authenticate user before page loads
You may want to check if the user is logged in before your page loads.
We’re going to use the getCurrentUser query inside
getServerSideProps() by calling the query directly. Then you can check
if the user is logged in on the server and use the built-in Next.js
redirect property.
import {Routes, BlitzPage} from "@blitzjs/next"
import {gSSP} from "src/blitz-server"
import getCurrentUser from "src/users/queries/getCurrentUser"
export const getServerSideProps = gSSP(async ({ctx}) => {
const currentUser = await getCurrentUser(null, ctx)
if (currentUser) {
return {
props: {
user: currentUser,
},
}
} else {
return {
redirect: {
destination: Routes.LoginPage(),
permanent: false,
},
}
}
})
Return types when data fetching on the server
You can set the types returned from the Next.js data fetching functions.
All Blitz.js wrappers for the Next.js functions accept a generic. Same
with the BlitzPage type.
So for example, we can use some typescript utilities to help use get the
types returned by getCurrentUser()
import {Routes, BlitzPage} from "@blitzjs/next"
import {gSSP} from "src/blitz-server"
import getCurrentUser from "src/users/queries/getCurrentUser"
type TCurrentUser = Awaited<ReturnType<typeof getCurrentUser>>
export const getServerSideProps = gSSP<{user: TCurrentUser}>(async ({ctx}) => {
const currentUser = await getCurrentUser(null, ctx)
if (currentUser) {
return {
props: {
user: currentUser,
},
}
} else {
return {
redirect: {
destination: Routes.LoginPage(),
permanent: false,
},
}
}
})
const Page: BlitzPage<{user: TCurrentUser}> = ({user}) => {
return (
<Layout title="Page">
<div className="container">
<p>User Page</p>
{user && <p>{user.email}</p>}
</div>
</Layout>
)
}
export default Page
Handling errors on initial page load
There’s an edge case where you may be throwing an error in a query that’s
being called on an initial page load, causing a server error instead of
hitting the <ErrorBoundary />. This is because when initially loading
the page, there is no ErrorBoundary component rendered until _app.tsx is
mounted. Though, this is expected behaviour, there is a workaround.
For an example, in a query where the user is not found you can create a
NotFoundError() then return the status code.
export default resolver.pipe(resolver.zod(GetUser), async (input) => {
const {id} = input
const user = await db.user.findFirst({where: {id}})
if (!user) {
const userError = new NotFoundError("User not found")
return {
error: userError.statusCode,
}
} else {
return {
user,
}
}
})
Then on the server (in this case getServerSideProps()) you can call the
query and if the error key is found in the return object then show an
error.
export const getServerSideProps = gSSP(async ({ ctx }) => {
const user = await getUser({ 1 }, ctx)
if("error" in user) {
return { props: { error: user.error}}
} else {
return { props: { user }}
}
})
You can also catch server errors in _app.tsx and show the errors with a
toast component.
function MyApp({Component, pageProps}: AppProps) {
const getLayout = Component.getLayout || ((page) => page)
if (pageProps.error) {
return <ToastComponent>{pageProps.error.statusCode}</ToastComponent>
}
return (
<ErrorBoundary FallbackComponent={RootErrorFallback}>
{getLayout(<Component {...pageProps} />)}
</ErrorBoundary>
)
}