Class: Middleware::AnonymousCache

Inherits:
Object
  • Object
show all
Defined in:
lib/middleware/anonymous_cache.rb

Defined Under Namespace

Classes: Helper

Constant Summary collapse

PAYLOAD_INVALID_REQUEST_METHODS = 
%w[GET HEAD]

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(app, settings = {}) ⇒ AnonymousCache

Returns a new instance of AnonymousCache.



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# File 'lib/middleware/anonymous_cache.rb', line 340

def initialize(app, settings = {})
  @app = app
end

Class Method Details

.anon_cache(env, duration) ⇒ Object 



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# File 'lib/middleware/anonymous_cache.rb', line 42

def self.anon_cache(env, duration)
  env["ANON_CACHE_DURATION"] = duration
end

.build_cache_key(helper) ⇒ Object 



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# File 'lib/middleware/anonymous_cache.rb', line 37

def self.build_cache_key(helper)
  compile_key_builder unless defined?(@@compiled)
  __compiled_key_builder(helper)
end

.cache_key_segments ⇒ Object 



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# File 'lib/middleware/anonymous_cache.rb', line 10

def self.cache_key_segments
  @@cache_key_segments ||= {
    m: "key_is_mobile?",
    c: "key_is_crawler?",
    o: "key_is_old_browser?",
    d: "key_is_modern_mobile_device?",
    b: "key_has_brotli?",
    t: "key_cache_theme_ids",
    ca: "key_compress_anon",
    l: "key_locale",
  }
end

.clear_all_cache! ⇒ Object 



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# File 'lib/middleware/anonymous_cache.rb', line 46

def self.clear_all_cache!
  if Rails.env.production?
    raise "for perf reasons, clear_all_cache! cannot be used in production."
  end
  Discourse.redis.keys("ANON_CACHE_*").each { |k| Discourse.redis.del(k) }
end

.compile_key_builder ⇒ Object

Compile a string builder method that will be called to create an anonymous cache key



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# File 'lib/middleware/anonymous_cache.rb', line 25

def self.compile_key_builder
  method = +"def self.__compiled_key_builder(h)\n  \""
  cache_key_segments.each do |k, v|
    raise "Invalid key name" unless k =~ /\A[a-z]+\z/
    raise "Invalid method name" unless v =~ /\Akey_[a-z_\?]+\z/
    method << "|#{k}=#\{h.#{v}}"
  end
  method << "\"\nend"
  eval(method) # rubocop:disable Security/Eval
  @@compiled = true
end

.disable_anon_cache ⇒ Object 



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# File 'lib/middleware/anonymous_cache.rb', line 53

def self.disable_anon_cache
  @@disabled = true
end

.enable_anon_cache ⇒ Object 



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# File 'lib/middleware/anonymous_cache.rb', line 57

def self.enable_anon_cache
  @@disabled = false
end

Instance Method Details

#call(env) ⇒ Object 



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# File 'lib/middleware/anonymous_cache.rb', line 346

def call(env)
  return @app.call(env) if defined?(@@disabled) && @@disabled

  if PAYLOAD_INVALID_REQUEST_METHODS.include?(env[Rack::REQUEST_METHOD]) &&
       env[Rack::RACK_INPUT].size > 0
    return 413, { "Cache-Control" => "private, max-age=0, must-revalidate" }, []
  end

  helper = Helper.new(env)
  force_anon = false

  if helper.blocked_crawler?
    env["discourse.request_tracker.skip"] = true
    return 403, {}, ["Crawler is not allowed!"]
  end

  if helper.should_force_anonymous?
    force_anon = env["DISCOURSE_FORCE_ANON"] = true
    helper.force_anonymous!
  end

  if (env["HTTP_DISCOURSE_BACKGROUND"] == "true") && (queue_time = env["REQUEST_QUEUE_SECONDS"])
    max_time = GlobalSetting.background_requests_max_queue_length.to_f
    if max_time > 0 && queue_time.to_f > max_time
      return [
        429,
        { "content-type" => "application/json; charset=utf-8" },
        [
          {
            errors: I18n.t("rate_limiter.slow_down"),
            extras: {
              wait_seconds: 5 + (5 * rand).round(2),
            },
          }.to_json,
        ]
      ]
    end
  end

  result =
    if helper.cacheable?
      helper.cached(env) || helper.cache(@app.call(env), env)
    else
      @app.call(env)
    end

  result[1]["Set-Cookie"] = "dosp=1; Path=/" if force_anon

  result
end