relocale

Overview

relocale redirects requests via the Accept-Language HTTP header. It is meant for static sites that need to redirect users based on their locale without any JavaScript or meta tags.

Installation

Before you start, you need to make sure that the relocale binary is installed somewhere. I will leave that part up to you.

Preparation

Create the relocale user:

useradd --system --shell /bin/false relocale

Locale configuration

Here is an example of how a configuration file could be written:

# Mandatory fallbacks which are used when no or empty values have been provided.
locale = 'en'
destination = '/${locale}${path}'

[network]
# Network address for relocale.
# This defaults to localhost:10451.
address = 'localhost:10451'

[locales]
# This regular expression will set the locale to 'en' if the client's locale
# matches 'en', 'en-US', ...
en.alias = '^en-.+$'

de.alias = '^de-.+$'

# The destination path which will be redirected to.
# This is a template string with the following predefined parameters:
# * path: Original request path
# * locale: Current locale
de.destination = '/${locale}${path}'

Service configuration

[Unit]
Description=relocale redirection service
After=network.target

[Service]
Type=simple
ExecStart=/usr/local/bin/relocale --config %i
ProtectSystem=strict
ReadOnlyPaths=/etc/relocale
WorkingDirectory=/etc/relocale
TimeoutStopSec=20
KillMode=mixed
Restart=on-failure
User=relocale
Group=relocale

[Install]
WantedBy=multi-user.target

Next, put the systemd unit file (e.g. as relocale@.service) into /etc/systemd/system. This unit file might not work for every setup out there, so make sure to modify it as needed.

Reverse proxy

server {
    # Change this to match your server's name or domain.
    server_name example.com;

    # This matches any path without the available locales 'en' and 'de' at the
    # start.
    location ~ ^/(?!(de|en)) {
        # Change this to match relocale's configuration.
        proxy_pass http://localhost:10451;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }

    # Every other request will serve a static file.
    location / {
        root /srv/http/example.com;
        index index.html;
    }

    # Your TLS configuration goes here.
    listen 80;
}