Dealing with errors in Next.js 13 with middleware: a comprehensive guide

Question

Dealing with errors in Next.js 13 with middleware: a comprehensive guide

My attempt to manage exceptions in Next.js 13 using middleware is not producing the desired results. Below is my current code:

import { NextRequest, NextFetchEvent, NextResponse } from "next/server"

export function middleware(req: NextRequest, event: NextFetchEvent) {
    try {
        return NextResponse.next()
    } catch (error: Error | any) {
        return NextResponse.json({
            error: {
                message: error.message,
                status: error.status,
            }
        })
    }
}

I anticipated the middleware would capture exceptions and provide a JSON response with error details. However, it appears that instead of functioning as expected, the code simply returns a 500 status error when an exception occurs elsewhere in the application, leading to a crash.

What am I missing here? Are there alternative methods for managing exceptions in Next.js 13 using middleware? Any suggestions or assistance would be greatly valued.

typescript next.js next.js13

Answer 1

Answer №1

The latest feature of Next.js middleware focuses on handling incoming network requests and applying transformations to all application routes. However, it does not manage errors that occur outside the request/response lifecycle.

When using a try-catch block in your middleware function, it only encapsulates the NextResponse.next() statement. Any exceptions occurring elsewhere in the application will not be caught by this block.

For further insights into this topic, check out these discussions on Next.js GitHub:

1- https://github.com/vercel/next.js/discussions/17832

2- https://github.com/vercel/next.js/discussions/32230

Considering the current situation, it may be more effective to implement error handling separately in different parts of the application. This could involve incorporating error boundaries in React components, utilizing try-catch blocks in API routes, or exploring third-party error tracking services like @sentry/nextjs for centralized error logging.

Answer 2

The latest feature of Next.js middleware focuses on handling incoming network requests and applying transformations to all application routes. However, it does not manage errors that occur outside the request/response lifecycle.

When using a try-catch block in your middleware function, it only encapsulates the NextResponse.next() statement. Any exceptions occurring elsewhere in the application will not be caught by this block.

For further insights into this topic, check out these discussions on Next.js GitHub:

1- https://github.com/vercel/next.js/discussions/17832

2- https://github.com/vercel/next.js/discussions/32230

Considering the current situation, it may be more effective to implement error handling separately in different parts of the application. This could involve incorporating error boundaries in React components, utilizing try-catch blocks in API routes, or exploring third-party error tracking services like @sentry/nextjs for centralized error logging.

Answer 3

Answer №2

Recently, I encountered a similar limitation while working with the latest Next.js middleware and implementing global error handling for API routes.

To overcome this challenge, I developed a custom apiHandler wrapper that incorporates both global middleware and exception handling:

import { NextRequest, NextResponse } from 'next/server';
import { errorHandler, jwtMiddleware, validateMiddleware } from './';

export { apiHandler };

function apiHandler(handler: any) {
    const wrappedHandler: any = {};
    const httpMethods = ['GET', 'POST', 'PUT', 'PATCH', 'DELETE'];

    // Implementing middleware and global error handler for each method
    httpMethods.forEach(method => {
        if (typeof handler[method] !== 'function')
            return;

        wrappedHandler[method] = async (req: NextRequest, ...args: any) => {
            try {
                const json = await req.json();
                req.json = () => json;
            } catch {}

            try {
                await jwtMiddleware(req);
                await validateMiddleware(req, handler[method].schema);

                const responseBody = await handler[method](req, ...args);
                return NextResponse.json(responseBody || {});
            } catch (err: any) {
                return errorHandler(err);
            }
        };
    });

    return wrappedHandler;
}

Below is an example of an API route (/api/account/login) utilizing the apiHandler:

import { cookies } from 'next/headers';
import joi from 'joi';
import { usersRepo } from '_helpers/server';
import { apiHandler } from '_helpers/server/api';

module.exports = apiHandler({
    POST: login
});

async function login(req: Request) {
    const body = await req.json();
    const { user, token } = await usersRepo.authenticate(body);

    cookies().set('authorization', token, { httpOnly: true });

    return user;
}

login.schema = joi.object({
    username: joi.string().required(),
    password: joi.string().required()
});

You can access the complete project at

Answer 4

Recently, I encountered a similar limitation while working with the latest Next.js middleware and implementing global error handling for API routes.

To overcome this challenge, I developed a custom apiHandler wrapper that incorporates both global middleware and exception handling:

import { NextRequest, NextResponse } from 'next/server';
import { errorHandler, jwtMiddleware, validateMiddleware } from './';

export { apiHandler };

function apiHandler(handler: any) {
    const wrappedHandler: any = {};
    const httpMethods = ['GET', 'POST', 'PUT', 'PATCH', 'DELETE'];

    // Implementing middleware and global error handler for each method
    httpMethods.forEach(method => {
        if (typeof handler[method] !== 'function')
            return;

        wrappedHandler[method] = async (req: NextRequest, ...args: any) => {
            try {
                const json = await req.json();
                req.json = () => json;
            } catch {}

            try {
                await jwtMiddleware(req);
                await validateMiddleware(req, handler[method].schema);

                const responseBody = await handler[method](req, ...args);
                return NextResponse.json(responseBody || {});
            } catch (err: any) {
                return errorHandler(err);
            }
        };
    });

    return wrappedHandler;
}

Below is an example of an API route (/api/account/login) utilizing the apiHandler:

import { cookies } from 'next/headers';
import joi from 'joi';
import { usersRepo } from '_helpers/server';
import { apiHandler } from '_helpers/server/api';

module.exports = apiHandler({
    POST: login
});

async function login(req: Request) {
    const body = await req.json();
    const { user, token } = await usersRepo.authenticate(body);

    cookies().set('authorization', token, { httpOnly: true });

    return user;
}

login.schema = joi.object({
    username: joi.string().required(),
    password: joi.string().required()
});

You can access the complete project at

Answer 5

Answer №3

The Edge middleware's error handling capabilities are limited by the constraints of the standard Web API, offering only a few options for managing errors. When NextResponse.error() is used, it triggers a promise rejection for the fetch request and displays the not-found page.

To address this limitation, I developed a workaround utilizing Response.rewrite within a middleware exception handler that redirects users to an error page. The middleware logic invokes the exception handler, particularly in scenarios like a 401 error. Additionally, the exception handler is activated when the next-connect Edge router promise is rejected.

export async function handleException(req: NextRequest, status: number, message?: string) {
    const base64 = btoa(JSON.stringify({ success: false, status, message }));
    const rewriteURL = new URL(`/error/${base64}`, req.url);
    return NextResponse.rewrite(rewriteURL);
}

This approach leads the client to display the error page at /error/[base64]/page.tsx.

'use server';

export default async function Error({ params }) {
    const decodedParams = decodeURIComponent(params.base64);
    const errorDetails = JSON.parse(atob(decodedParams));

    return (
        <div>
            <h2>{errorDetails.status}</h2>
            <span>{errorDetails.message}</span>
        </div>
    );
}

Answer 6

The Edge middleware's error handling capabilities are limited by the constraints of the standard Web API, offering only a few options for managing errors. When NextResponse.error() is used, it triggers a promise rejection for the fetch request and displays the not-found page.

To address this limitation, I developed a workaround utilizing Response.rewrite within a middleware exception handler that redirects users to an error page. The middleware logic invokes the exception handler, particularly in scenarios like a 401 error. Additionally, the exception handler is activated when the next-connect Edge router promise is rejected.

export async function handleException(req: NextRequest, status: number, message?: string) {
    const base64 = btoa(JSON.stringify({ success: false, status, message }));
    const rewriteURL = new URL(`/error/${base64}`, req.url);
    return NextResponse.rewrite(rewriteURL);
}

This approach leads the client to display the error page at /error/[base64]/page.tsx.

'use server';

export default async function Error({ params }) {
    const decodedParams = decodeURIComponent(params.base64);
    const errorDetails = JSON.parse(atob(decodedParams));

    return (
        <div>
            <h2>{errorDetails.status}</h2>
            <span>{errorDetails.message}</span>
        </div>
    );
}

Dealing with errors in Next.js 13 with middleware: a comprehensive guide

Answer №1

Answer №2

Answer №3

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