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Middleware edge functions do not support POST request with "Expect: 100-continue" HTTP header

See original GitHub issue

Steps to reproduce:

Add any valid _middleware.ts to a NextJS application.
Deploy to Vercel
Make a POST request to any url where that middleware will be run with: Expect: 100-continue as an HTTP header, and any non-empty body content.

Result:

We get a 502 Bad Gateway with the following response body:

An internal error occurred with Vercel.

INTERNAL_EDGE_FUNCTION_CONNECTION_CLOSED

In the function log, we get a message that the middleware was called, but the code does not execute (adding a console.info in the middleware does not show up in the function log)

Expected result:

Middleware and page or api executes appropriately.

Expect: 100-continue is part of the HTTP 1.1 spec and should be implemented, or should be documented explicitly as not implemented.

Issue Analytics

State:
Created a year ago
Reactions:6
Comments:29 (2 by maintainers)

Top GitHub Comments

1reaction

littleStudentcommented, Sep 9, 2022

👋 We are having the same issue since 12hours ago as well. Seems like POST requests from some locations (confirmed via VPN for the UK) run into a 502 - INTERNAL_EDGE_FUNCTION_CONNECTION_CLOSED

From other parts of the world we do not see such a problem

0reactions

viekocommented, Nov 4, 2022

We brought back the middleware, working as expected. There was an issue on Vercel’s end which has been fixed.