#   This file is included strictly as an example of how Nginx can be configured
#   to work with CryptPad. This example WILL NOT WORK AS IS. For best results,
#   compare the sections of this configuration file against a working CryptPad
#   installation (http server by the Nodejs process). If you are using CryptPad
#   in production, contact sales@cryptpad.fr

server {
    listen 443 ssl http2;

    # CryptPad serves static assets over these two domains.
    # `main_domain` is what users will enter in their address bar.
    # Privileged computation such as key management is handled in this scope
    # UI content is loaded via the `sandbox_domain`.
    # "Content Security Policy" headers prevent content loaded via the sandbox
    # from accessing privileged information.
    # These variables must be different to take advantage of CryptPad's sandboxing techniques.
    # In the event of an XSS vulnerability in CryptPad's front-end code
    # this will limit the amount of information accessible to attackers.
    set $main_domain "your-main-domain.com";
    set $sandbox_domain "your-sandbox-domain.com";

    # CryptPad's dynamic content (websocket traffic and encrypted blobs)
    # can be served over separate domains. Using dedicated domains (or subdomains)
    # for these purposes allows you to move them to a separate machine at a later date
    # if you find that a single machine cannot handle all of your users.
    # If you don't use dedicated domains, this can be the same as $main_domain
    # If you do, they'll be added as exceptions to any rules which block connections to remote domains.
    set $api_domain "api.your-main-domain.com";
    set $files_domain "files.your-main-domain.com";

    # nginx doesn't let you set server_name via variables, so you need to hardcode your domains here
    server_name your-main-domain.com your-sandbox-domain.com;

    # You'll need to Set the path to your certificates and keys here
    ssl_certificate         /home/cryptpad/.acme.sh/your-main-domain.com/fullchain.cer;
    ssl_certificate_key     /home/cryptpad/.acme.sh/your-main-domain.com/your-main-domain.com.key;
    ssl_trusted_certificate /home/cryptpad/.acme.sh/your-main-domain.com/ca.cer;

    # diffie-hellman parameters are used to negotiate keys for your session
    # generate strong parameters using the following command
    ssl_dhparam /etc/nginx/dhparam.pem; # openssl dhparam -out /etc/nginx/dhparam.pem 4096

    # Speeds things up a little bit when resuming a session
    ssl_session_timeout 5m;
    ssl_session_cache shared:SSL:5m;

    # You'll need nginx 1.13.0 or better to support TLSv1.3
    ssl_protocols TLSv1.2 TLSv1.3;

    # https://cipherli.st/
    ssl_ciphers EECDH+AESGCM:EDH+AESGCM;
    ssl_ecdh_curve secp384r1; # Requires nginx >= 1.1.0

    add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;
    add_header X-XSS-Protection "1; mode=block";
    add_header X-Content-Type-Options nosniff;
    # add_header X-Frame-Options "SAMEORIGIN";

    # Insert the path to your CryptPad repository root here
    root /home/cryptpad/cryptpad;
    index index.html;
    error_page 404 /customize.dist/404.html;

    # any static assets loaded with "ver=" in their URL will be cached for a year
    if ($args ~ ver=) {
        set $cacheControl max-age=31536000;
    }
    # Will not set any header if it is emptystring
    add_header Cache-Control $cacheControl;

    # CSS can be dynamically set inline, loaded from the same domain, or from $main_domain
    set $styleSrc   "'unsafe-inline' 'self' ${main_domain}";

    # connect-src restricts URLs which can be loaded using script interfaces
    set $connectSrc "'self' https://${main_domain} wss://${main_domain} $main_domain https://${api_domain} blob:";

    # fonts can be loaded from data-URLs or the main domain
    set $fontSrc    "'self' data: ${main_domain}";

    # images can be loaded from anywhere, though we'd like to deprecate this as it allows the use of images for tracking
    set $imgSrc     "'self' data: * blob: ${main_domain}";

    # frame-src specifies valid sources for nested browsing contexts.
    # this prevents loading any iframes from anywhere other than the sandbox domain
    set $frameSrc   "'self' ${sandbox_domain} blob:";

    # specifies valid sources for loading media using video or audio
    set $mediaSrc   "'self' data: * blob: ${main_domain}";

    # defines valid sources for webworkers and nested browser contexts
    # deprecated in favour of worker-src and frame-src
    set $childSrc   "https://${main_domain}";

    # specifies valid sources for Worker, SharedWorker, or ServiceWorker scripts.
    # supercedes child-src but is unfortunately not yet universally supported.
    set $workerSrc  "https://${main_domain}";

    # script-src specifies valid sources for javascript, including inline handlers
    set $scriptSrc  "'self' ${main_domain}";

    set $unsafe 0;
    # the following assets are loaded via the sandbox domain
    # they unfortunately still require exceptions to the sandboxing to work correctly.
    if ($uri = "/pad/inner.html") { set $unsafe 1; }
    if ($uri = "/sheet/inner.html") { set $unsafe 1; }
    if ($uri = "/common/onlyoffice/web-apps/apps/spreadsheeteditor/main/index.html") { set $unsafe 1; }

    # everything except the sandbox domain is a privileged scope, as they might be used to handle keys
    if ($host != sandbox.cryptpad.info) { set $unsafe 0; }

    # privileged contexts allow a few more rights than unprivileged contexts, though limits are still applied
    if ($unsafe) {
        set $scriptSrc "'self' 'unsafe-eval' 'unsafe-inline' ${main_domain}";
    }

    # Finally, set all the rules you composed above.
    add_header Content-Security-Policy "default-src 'none'; child-src $childSrc; worker-src $workerSrc; media-src $mediaSrc; style-src $styleSrc; script-src $scriptSrc; connect-src $connectSrc; font-src $fontSrc; img-src $imgSrc; frame-src $frameSrc;";

    # The nodejs process can handle all traffic whether accessed over websocket or as static assets
    # We prefer to serve static content from nginx directly and to leave the API server to handle
    # the dynamic content that only it can manage. This is primarily an optimization
    location ^~ /cryptpad_websocket {
        proxy_pass http://localhost:3000;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

        # WebSocket support (nginx 1.4)
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection upgrade;
    }

    location ^~ /customize.dist/ {
        # This is needed in order to prevent infinite recursion between /customize/ and the root
    }
    # try to load customizeable content via /customize/ and fall back to the default content
    # located at /customize.dist/
    # This is what allows you to override behaviour.
    location ^~ /customize/ {
        rewrite ^/customize/(.*)$ $1 break;
        try_files /customize/$uri /customize.dist/$uri;
    }

    # /api/config is loaded once per page load and is used to retrieve
    # the caching variable which is applied to every other resource
    # which is loaded during that session.
    location = /api/config {
        proxy_pass http://localhost:3000;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    }

    # encrypted blobs are immutable and are thus cached for a year
    location ^~ /blob/ {
        add_header Cache-Control max-age=31536000;
        try_files $uri =404;
    }

    # the "block-store" serves encrypted payloads containing users' drive keys
    # these payloads are unlocked via login credentials. They are mutable
    # and are thus never cached. They're small enough that it doesn't matter, in any case.
    location ^~ /block/ {
        add_header Cache-Control max-age=0;
        try_files $uri =404;
    }

    # This block provides an alternative means of loading content
    # otherwise only served via websocket. This is solely for debugging purposes,
    # and is thus not allowed by default.
    #location ^~ /datastore/ {
        #add_header Cache-Control max-age=0;
        #try_files $uri =404;
    #}

    # The nodejs server has some built-in forwarding rules to prevent
    # URLs like /pad from resulting in a 404. This simply adds a trailing slash
    # to a variety of applications.
    location ~ ^/(register|login|settings|user|pad|drive|poll|slide|code|whiteboard|file|media|profile|contacts|todo|filepicker|debug|kanban|sheet|support|admin|notifications|teams)$ {
        rewrite ^(.*)$ $1/ redirect;
    }

    # Finally, serve anything the above exceptions don't govern.
    try_files /www/$uri /www/$uri/index.html /customize/$uri;
}