This plugin is deprecated

Impostor 1.9.0 includes this plugin, as tha base game of Among Us has required the use of HTTP matchmaking for a while. You should switch to the built in server, see the migration guide

If you are using 1.8.4 or lower, the original plugin readme is hidden here

Impostor.Http

Adds HTTP matchmaking to Impostor

Installation

Install Impostor first. You need version 1.8.1 or newer.
Install ASP.NET Core Runtime 7 as well
Download Impostor.Http.dll from the GitHub Releases and put it in Impostor's plugin folder
Finally, if you want to change the default configuration, you need to create a configuration file for this plugin. See the next section for this.

Configuration

Configuration is read from the config_http.json file or from environment variables prefixed with IMPOSTOR_HTTP_. You can copy over this file for the default settings. These are the possible keys:

Key	Default	Description
ListenIp	`127.0.0.1`	IP address to listen on. Use 127.0.0.1 if using a reverse proxy like nginx (recommended), use 0.0.0.0 if exposed directly (not recommended)
ListenPort	22023	Port the HTTP matchmaking server is running on.
UseHttps	`false`	Set to true if using encrypted communication to your reverse proxy or if you're exposing this server directly to the internet (not recommended)
CertificatePath	not set	If UseHttps is enable, set this property to the path of your SSL certificate in PFX format.

HTTPS configuration

To enable support for Android/iOS devices, you need to enable HTTPS. If you don't need to support phones, you can skip this section. Enabling HTTPS can be done in one of two ways:

1. Use a Reverse Proxy like nginx, apache or caddy

The reverse proxy can terminate HTTPS for you. To configure this:

Set ListenIp to 127.0.0.1 so that Impostor.Http can only be reached using the Reverse Proxy.
Set UseHttps to false.
Use Let's Encrypt or a similar service to get an SSL certificate. We recommend Certbot. Self-signed certificates are not enough.
Configure your reverse proxy. For nginx, we have a sample config available. For the other servers, please refer to your server's documentation.

Nginx server configuration

Replace YOUR_SERVER_NAME_HERE with the hostname of your server:

server {
    listen 443 ssl http2;
    server_name YOUR_SERVER_NAME_HERE;

    ssl_certificate /etc/letsencrypt/live/YOUR_SERVER_NAME_HERE/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/YOUR_SERVER_NAME_HERE/privkey.pem;
    ssl_trusted_certificate /etc/letsencrypt/live/YOUR_SERVER_NAME_HERE/fullchain.pem;

    include /etc/nginx/ssl_ciphers; # https://ssl-config.mozilla.org/#server=nginx&version=1.16.1&config=intermediate&openssl=1.1.1d&guideline=5.4

    # generated 2023-03-19, Mozilla Guideline v5.6, nginx 1.17.7, OpenSSL 1.1.1d, intermediate configuration, no HSTS
    # https://ssl-config.mozilla.org/#server=nginx&version=1.17.7&config=intermediate&openssl=1.1.1d&hsts=false&guideline=5.6
    ssl_session_timeout 1d;
    ssl_session_cache shared:MozSSL:10m;  # about 40000 sessions
    ssl_session_tickets off;

    # curl https://ssl-config.mozilla.org/ffdhe2048.txt > /path/to/dhparam
    ssl_dhparam /path/to/dhparam;

    # intermediate configuration
    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384;
    ssl_prefer_server_ciphers off;

    # OCSP stapling
    ssl_stapling on;
    ssl_stapling_verify on;

    location / {
        proxy_pass http://localhost:22023;
        proxy_pass_header Server;
        proxy_buffering off;
        proxy_redirect off;
        proxy_set_header X-Real-IP $remote_addr;  # http://wiki.nginx.org/HttpProxyModule
        proxy_set_header X-Forwarded-For $remote_addr;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header Host $host;
        proxy_http_version 1.1;  # recommended with keepalive connections
    }

}

2. Use the Https feature of Impostor.Http

We don't recommend using this option for a couple reasons: it is not very flexible as it requires PFX certificates and it needs to be restarted to reload the certificate. But in case you really don't want to use a reverse proxy, here's how to do it:

Set ListenIp to 0.0.0.0 so that your server can be reached externally.
Set UseHttps to true.
Use Let's Encrypt or a similar service to get an SSL certificate. We recommend Certbot. Self-signed certificates are not enough.
Convert your certificate to PFX format, for example using OpenSSL: openssl pkcs12 -export -out certificate_fullchain.pfx -inkey privkey.pem -in fullchain.pem.
Set CertificatePath to the path to this certificate_fullchain.pfx file.

Impostor / Impostor.Http