Why does Membrane API Gateway return 404 Not Found with Invalid path or method?

Membrane received a request on one of its ports, but none of the APIs configured for that port matches the request's host, HTTP method and path. Membrane does not know where to route the request and answers with 404 Not Found.

How do I fix the Invalid path or method error in Membrane?

Compare the request with the api definitions in your apis.yaml. Check the path prefix, the method and host restrictions, and for OpenAPI based APIs the base path from the servers field. Either call the correct URL or add an API that matches the request.

How do I hide the details in Membrane error responses?

Enable production mode by adding a configuration document with production: true to your apis.yaml. Membrane then leaves out detailed information from error responses.

404 Not Found: Invalid Path or Method

Membrane API Gateway returns 404 Not Found with the title Invalid path or method when a request arrives on one of its ports, but no API matches the request. Membrane does not know where to route the request and rejects it.

The Error Response

The response contains the status 404 Not Found, the title Invalid path or method, the message The requested path or HTTP method is not supported., the problem type https://membrane-api.io/problems/user and a link to this page. The type user means that the request or the configuration caused the problem, not an internal failure of the gateway.

How Membrane Routes Requests

For every incoming request, Membrane looks for an api whose criteria all match the request:

Criterion	Configuration	Default
Port	`port`	Required
Host header	`host`	Any host
HTTP method	`method`	Any method
Path	`path.uri`, or the base paths of an `openapi` document	Any path

If no API on the port matches, Membrane answers with this error. The APIs are checked in the order in which they appear in the configuration, and the first match wins.

Common Causes

The Path Does Not Match

A path is matched as a prefix. The following API accepts /shop/products and /shop/orders/7, but a request to /products or /Shop fails with Invalid path or method:

api:
  port: 2000
  path:
    uri: /shop
  target:
    url: https://api.predic8.de

api:
  port: 2000
  path:
    uri: /shop
  target:
    url: https://api.predic8.de

Check the request URL for typos, missing prefixes and case. If isRegExp: true is set, the uri is treated as a regular expression, so check that the expression matches the path.

The Method Is Restricted

An API with a method accepts only that HTTP method. A POST to this API is rejected:

api:
  port: 2000
  method: GET
  path:
    uri: /shop
  target:
    url: https://api.predic8.de

api:
  port: 2000
  method: GET
  path:
    uri: /shop
  target:
    url: https://api.predic8.de

Remove method to accept all methods, or add another API for the missing method.

The Host Does Not Match

With host set, the Host header of the request must match. Calling the gateway by IP address or through localhost instead of the configured host name fails.

The OpenAPI Base Path Does Not Match

An API deployed from an OpenAPI document is routed using the paths of the servers URLs in that document. If the servers URL is https://api.example.com/shop/v2, requests must start with /shop/v2.

The Request Hits the Wrong Port

If there is no API for the path on the port you are calling, the request cannot be routed, even if another port has a matching API. Check the port in the URL against the port of your APIs.

How to Fix It

Note the port, Host header, method and path of the failing request.
Compare them with the api definitions in your apis.yaml.
Either correct the request, or change or add an API that matches it.

To accept all remaining requests on a port, place a catch-all API without path and method after the more specific ones:

api:
  port: 2000
  path:
    uri: /shop
  target:
    url: https://api.predic8.de
---
api:
  port: 2000
  flow:
    - return:
        status: 404

api:
  port: 2000
  path:
    uri: /shop
  target:
    url: https://api.predic8.de
---
api:
  port: 2000
  flow:
    - return:
        status: 404

Hide Details in Production

By default, Membrane runs in development mode and adds details to error responses that help you find the problem. These details may reveal information about your setup. In production, turn them off:

configuration:
  production: true

configuration:
  production: true

Add the configuration document to your apis.yaml and separate it from the APIs with ---.