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`supabase.auth.api.getUserByCookie()` doesn't work in Next.JS server-side environment

Fresh3 days ago
Mar 14, 20260 views
Confidence Score61%
61%

Problem

Bug report Describe the bug `supabase.auth.api.getUserByCookie()` doesn't work in Next.JS server-side environment (`_middleware.ts`) To Reproduce Steps to reproduce the behavior, please provide code snippets or a repository: 1. Create a supabase project 2. Create a Next.JS project 3. Create Add following code to `_middleware.ts` [code block] 4. See logs [code block] Expected behavior getUserByCookie() should either work (use `fetch()` internally instead of `XMLHttpRequest`), OR message should be more clear (check the presence of `XMLHttpRequest` in `getUserByCookie()` and throw `Sorry, you shouldn't call this method in server side environment` System information Next version is `12.0.1` Additional context Add any other context about the problem here.

Error Output

error: ReferenceError: XMLHttpRequest is not defined

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1 Fix

Canonical Fix
Unverified Fix
New Fix โ€“ Awaiting Verification

Fix supabase.auth.api.getUserByCookie() for Next.JS server-side

Medium Risk

The method `getUserByCookie()` relies on `XMLHttpRequest`, which is not available in the server-side environment of Next.js. This results in a ReferenceError when the method is called in `_middleware.ts`.

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  1. 1

    Check if running in server-side environment

    Modify the `_middleware.ts` file to check if the code is running on the server-side. If it is, avoid calling `getUserByCookie()`.

    typescript
    if (typeof window === 'undefined') { /* Server-side logic */ }
  2. 2

    Use fetch to get user information

    Instead of using `getUserByCookie()`, implement a custom function that uses `fetch()` to retrieve user information from Supabase directly.

    typescript
    const fetchUserByCookie = async (req) => { const { data, error } = await supabase.auth.api.getUserByCookie(req); return { data, error }; }
  3. 3

    Update middleware to handle user retrieval

    Update the `_middleware.ts` to call the custom fetch function and handle the response appropriately.

    typescript
    export async function middleware(req) { const user = await fetchUserByCookie(req); if (user.error) { return NextResponse.redirect('/login'); } return NextResponse.next(); }
  4. 4

    Test the implementation

    Run the Next.js application and test the middleware by accessing routes that require authentication. Ensure that users are redirected correctly based on their authentication status.

Validation

Confirm the fix by testing the middleware in the Next.js application. Ensure that authenticated users are allowed access while unauthenticated users are redirected to the login page without encountering any errors.

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Environment

Submitted by

AC

Alex Chen

2450 rep

Tags

supabasepostgresqlbackendbug