###########

# mattermost
# This configuration file is for use by people behind some load balancer which already terminates SSL
# where the user may desire not to use backend letsencrypt SSL within a secured network.

# proxy cache
proxy_cache_path /var/cache/nginx levels=1:2 keys_zone=mattermost_cache:10m max_size=3g inactive=120m use_temp_path=off;

# upstream used in proxy_pass below
upstream backend {
    # ip where Mattermost is running; this relies on a working DNS inside the Docker network
    # and uses the hostname of the mattermost container (see service name in docker-compose.yml)
    server mattermost:8065;
    keepalive 64;
}

server {
    server_name _;
    listen 80;
    listen [::]:80;

    # logging
    access_log /var/log/nginx/mm.access.log;
    error_log /var/log/nginx/mm.error.log warn;

    # gzip for performance
    gzip on;
    gzip_vary on;
    gzip_proxied any;
    gzip_comp_level 6;
    gzip_types text/plain text/css text/xml application/json application/javascript application/rss+xml application/atom+xml image/svg+xml;

    ## security headers
    # https://securityheaders.com/
    # https://scotthelme.co.uk/tag/security-headers/
    add_header X-Frame-Options "SAMEORIGIN" always;
    add_header X-XSS-Protection "1; mode=block" always;
    add_header X-Content-Type-Options "nosniff" always;
    add_header Referrer-Policy no-referrer;
    add_header Strict-Transport-Security "max-age=63072000" always;
    add_header Permissions-Policy "interest-cohort=()";

    ## locations

    # disable Google bots from indexing this site
    location = /robots.txt {
        add_header Content-Type text/plain;
        return 200 "User-agent: *\nDisallow: /\n";
    }

    location ~ /api/v[0-9]+/(users/)?websocket$ {
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
        client_max_body_size 50M;
        proxy_set_header Host $http_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;
        proxy_set_header X-Frame-Options SAMEORIGIN;
        proxy_set_header Early-Data $ssl_early_data;
        proxy_buffers 256 16k;
        proxy_buffer_size 16k;
        client_body_timeout 60;
        send_timeout 300;
        lingering_timeout 5;
        proxy_connect_timeout 90;
        proxy_send_timeout 300;
        proxy_read_timeout 90s;
        proxy_http_version 1.1;
        proxy_pass http://backend;
    }

    location / {
        client_max_body_size 50M;
        proxy_set_header Connection "";
        proxy_set_header Host $http_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;
        proxy_set_header X-Frame-Options SAMEORIGIN;
        proxy_set_header Early-Data $ssl_early_data;
        proxy_buffers 256 16k;
        proxy_buffer_size 16k;
        proxy_read_timeout 600s;
        proxy_cache mattermost_cache;
        proxy_cache_revalidate on;
        proxy_cache_min_uses 2;
        proxy_cache_use_stale timeout;
        proxy_cache_lock on;
        proxy_http_version 1.1;
        proxy_pass http://backend;
    }
}