vcl 4.1;

import std;
import vsthrottle;

backend default {
  .host = "plik";
  .port = "8080";
  .max_connections = 100;
  .probe = {
    .url = "/";
    .interval = 10s;
    .timeout = 5s;
    .window = 5;
    .threshold = 3;
  }
  .connect_timeout       = 5s;
  .first_byte_timeout    = 90s;
  .between_bytes_timeout = 2s;
}

acl purge {
  "localhost";
  "127.0.0.1";
  "::1";
}

sub vcl_recv {
  unset req.http.X-Cache;
  unset req.http.X-Cache-Hits;

  set req.http.Host = regsub(req.http.Host, ":[0-9]+", "");
  unset req.http.proxy;
  set req.backend_hint = default;
  set req.url = std.querysort(req.url);
  set req.url = regsub(req.url, "\?$", "");

  if (req.restarts == 0) {
    if (req.http.X-Forwarded-For) {
      set req.http.X-Forwarded-For = req.http.X-Forwarded-For + ", " + client.ip;
    } else {
      set req.http.X-Forwarded-For = client.ip;
    }
  }

  if (vsthrottle.is_denied(client.identity, 100, 10s, 10s)) {
    return (synth(429, "Too Many Requests"));
  }

  if (req.method == "PURGE") {
    if (!client.ip ~ purge) {
      return (synth(405, "Not allowed."));
    }
    return (purge);
  }

  if (req.method == "BAN") {
    if (!client.ip ~ purge) {
      return (synth(405, "Not allowed."));
    }
    ban("req.http.host == " + req.http.host + " && req.url ~ " + req.url);
    return (synth(200, "Banned"));
  }

  if (req.method != "GET" && req.method != "HEAD" && req.method != "OPTIONS") {
    return (pass);
  }

  if (req.http.Authorization) {
    return (pass);
  }

  # upload / status / api / ajax poza cache
  if (
    req.url ~ "(?i)^/(upload|api|status|progress|session|login|logout)(/|$)" ||
    req.url ~ "(?i)/(ajax|ahah)/"
  ) {
    return (pass);
  }

  if (req.http.Accept-Encoding) {
    if (req.url ~ "(?i)\.(jpg|jpeg|png|gif|webp|ico|svg|woff2?|ttf|eot|mp4|mp3|pdf|zip|7z|gz|bz2)$") {
      unset req.http.Accept-Encoding;
    } elseif (req.http.Accept-Encoding ~ "gzip") {
      set req.http.Accept-Encoding = "gzip";
    } else {
      unset req.http.Accept-Encoding;
    }
  }

  # jeśli są cookies, to:
  # - dla plików statycznych ignorujemy
  # - dla reszty omijamy cache
  if (req.http.Cookie) {
    if (req.url ~ "(?i)\.(jpg|jpeg|png|gif|webp|ico|svg|js|css|woff2?|ttf|eot|pdf|zip|7z|gz|bz2|mp4|mp3)$") {
      unset req.http.Cookie;
    } else {
      return (pass);
    }
  }

  return (hash);
}

sub vcl_hash {
  if (req.http.X-Forwarded-Proto) {
    hash_data(req.http.X-Forwarded-Proto);
  }
}

sub vcl_hit {
  set req.http.X-Cache = "HIT";
  if (obj.ttl <= 0s && obj.grace > 0s) {
    set req.http.X-Cache = "HIT-GRACE";
  }
  return (deliver);
}

sub vcl_miss {
  set req.http.X-Cache = "MISS";
  return (fetch);
}

sub vcl_pass {
  set req.http.X-Cache = "PASS";
  return (fetch);
}

sub vcl_backend_response {
  # nie cache'uj błędów 5xx
  if (beresp.status == 500 || beresp.status == 503) {
    set beresp.uncacheable = true;
    set beresp.ttl = 0s;
    return (deliver);
  }

  # krótkie cache dla 404, umiarkowane dla redirectów
  if (beresp.status == 404) {
    set beresp.ttl = 5s;
  } elseif (beresp.status == 301 || beresp.status == 302) {
    set beresp.ttl = 10m;
  }

  if (bereq.url ~ "(?i)\.(jpg|jpeg|png|gif|webp|ico|svg|mp4|mp3|pdf|zip|7z|gz|bz2)$") {
    set beresp.do_gzip = false;
  } else {
    set beresp.do_gzip = true;
  }

  if (beresp.http.Cache-Control ~ "(?i)no-store|private") {
    set beresp.uncacheable = true;
    set beresp.ttl = 0s;
    return (deliver);
  }

  if (beresp.ttl <= 0s) {
    if (beresp.http.Cache-Control ~ "(?i)s-maxage=\d+") {
      set beresp.ttl = std.duration(
        regsub(beresp.http.Cache-Control, ".*(?i)s-maxage=(\d+).*", "\1") + "s",
        0s
      );
    } elseif (beresp.http.Cache-Control ~ "(?i)max-age=\d+") {
      set beresp.ttl = std.duration(
        regsub(beresp.http.Cache-Control, ".*(?i)max-age=(\d+).*", "\1") + "s",
        0s
      );
    }
  }

  if (beresp.ttl <= 0s) {
    if (bereq.url ~ "(?i)\.(jpg|jpeg|png|gif|webp|ico|svg|js|css|woff2?|ttf|eot|pdf|zip|7z|gz|bz2|mp4|mp3)$") {
      set beresp.ttl = 7d;
    } else {
      set beresp.ttl = 0s;
      set beresp.uncacheable = true;
      return (deliver);
    }
  }

  if (bereq.url ~ "(?i)\.(jpg|jpeg|png|gif|webp|ico|svg|js|css|woff2?|ttf|eot|pdf|zip|7z|gz|bz2|mp4|mp3)$") {
    unset beresp.http.Set-Cookie;
  }

  if (beresp.http.Surrogate-Control ~ "ESI/1.0") {
    unset beresp.http.Surrogate-Control;
    set beresp.do_esi = true;
  }

  if (beresp.ttl > 0s) {
    set beresp.grace = 10m;
    if (beresp.ttl > 1h) {
      set beresp.keep = 1h;
    } else {
      set beresp.keep = beresp.ttl;
    }
  } else {
    set beresp.grace = 0s;
    set beresp.keep = 0s;
  }

  if (beresp.http.Content-Length && std.integer(beresp.http.Content-Length, 0) > 1048576) {
    set beresp.do_stream = true;
  }

  return (deliver);
}

sub vcl_deliver {
  # Cache-Control tylko dla realnych plików
  if (req.url ~ "(?i)\.(jpg|jpeg|png|gif|webp|ico|svg|js|css|woff2?|ttf|eot|pdf|zip|7z|gz|bz2|mp4|mp3)$") {
    set resp.http.Cache-Control = "public, max-age=604800, immutable";
  } else {
    set resp.http.Cache-Control = "no-store, no-cache, must-revalidate, max-age=0";
  }

  unset resp.http.Expires;
  unset resp.http.Pragma;

  if (resp.status >= 500) {
    set resp.http.X-Cache = "ERROR";
  } elseif (obj.uncacheable) {
    set resp.http.X-Cache = "PASS";
    unset resp.http.Age;
  } elseif (obj.hits > 0) {
    set resp.http.X-Cache = "HIT";
    set resp.http.X-Cache-Hits = obj.hits;
  } else {
    set resp.http.X-Cache = "MISS";
    unset resp.http.Age;
  }

  unset resp.http.X-Url;
  unset resp.http.X-Host;
  unset resp.http.Via;
  unset resp.http.X-Varnish;
  unset resp.http.Server;
  unset resp.http.Content-Disposition;

  set resp.http.X-Frame-Options = "SAMEORIGIN";
}

sub vcl_synth {
  set resp.http.X-Cache = "SYNTH";
  unset resp.http.X-Varnish;

  if (resp.status == 429) {
    set resp.http.Content-Type = "text/plain; charset=utf-8";
    return (deliver);
  }
}