Matrix schema server

Simple and slim server to answer well-known requests for matrix.org servers based on the request host header, to be used behind a reverse proxy of your choice.

Features:

• Have a single server instance serve as many different domains on the same reverse proxy as required.
• Simple managment by passing through your JSON files queried by the Host-header.
• Low footprint (~8MB RAM, 10MB binary), no heavy dependencies (single binary), fast responses (~1ms).

Setup example

For my own domain klonmaschine.de I use the following docker-compose setup:

version: '3.7'

services:
  updater:
    image: adrianrudnik/matrix-wellknown-server:latest
    volumes:
      - ./schema:/var/schema
    ports:
      - 8080:8080

Now let's define the response to /.well-known/matrix/server if a request with an Host: klonmaschine.de header is received by placing a file into ./schema/klonmaschine.de.server.json:

{
  "m.server": "matrix.klonmaschine.de:8448"
}

The same for /.well-known/matrix/client requests, placed into ./schema/klonmaschine.de.client.json:

{
  "m.homeserver": {
    "base_url": "https://matrix.klonmaschine.de:8448"
  }
}

Now boot it up with docker-compose up -d and the following requests are answered correctly and offer CORS support as well:

https://klonmaschine.de/.well-known/matrix/server
http://klonmaschine.de/.well-known/matrix/client

Environment variables

The following configuration can be done by passing environment variables to this app:

Key	Description	Default
BIND_ADDR	HTTP bind address	:8080
SCHEMA_ROOT	Root folder for schema JSON files	/var/schema

Remarks

The element.io client does not use the server schema to resolve the homeserver. You need to specify the matrix server as full domain, in my example matrix.klonmaschine.de to connect to it.

Reserver proxy examples

Traefik

I use this slightly redacted version to serve the app:

http:
  routers:
    matrix-wellknown-server:
      rule: "PathPrefix(`/.well-known/matrix/`)"
      priority: 1000
      entryPoints:
        - https
      service: wellknown-server
      tls:
        certResolver: http-le
        
  services:
    wellknown-server:
      loadBalancer:
        servers:
          - url: "http://wellknown-server:8080"