Class: Mayu::Server::App

Inherits:
Object
  • Object
show all
Extended by:
T::Sig
Defined in:
lib/mayu/server/app.rb

Constant Summary collapse

DEV_ASSETS_TIMEOUT_SECONDS = 
4
DEV_ASSETS_RETRY_AFTER_SECONDS = 
2
PING_INTERVAL =

seconds

2
NANOID_RE = 
/[\w-]{21}/
MIME_TYPES = 
T.let(
  {
    eventstream: "application/vnd.mayu.eventstream",
    session: "application/vnd.mayu.session"
  },
  T::Hash[Symbol, String]
)

Instance Method Summary collapse

Constructor Details

#initialize(environment:) ⇒ App 



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# File 'lib/mayu/server/app.rb', line 29

def initialize(environment:)
  @environment = environment
  @metrics = T.let(environment.metrics, AppMetrics)
  @barrier = T.let(Async::Barrier.new, Async::Barrier)
  @stop = T.let(Async::Variable.new, Async::Variable)
  @sessions = T.let({}, T::Hash[String, Session])

  @runtime_assets =
    T.let(FileServer.new(@environment.js_runtime_path), FileServer)
  @static_assets =
    T.let(FileServer.new(@environment.path(:assets)), FileServer)
end

Instance Method Details

#call(request) ⇒ Object 



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# File 'lib/mayu/server/app.rb', line 85

def call(request)
  # The following line generates very noisy logs,
  # but can be useful when debugging.
  # Console.logger.info(self, "#{request.method} #{request.path}")

  Errors.handle_exceptions { handle_request(request) }
end

#clear_expired_sessions! ⇒ Object 



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# File 'lib/mayu/server/app.rb', line 43

def clear_expired_sessions!
  old_size = @sessions.size

  @sessions.delete_if do |id, session|
    next unless session.expired?(20)

    Console.logger.warn(self, "Session #{session.id} timed out")
    session.stop!
    @metrics.session_timeout_count.increment
    true
  end

  unless @sessions.size == old_size
    Console.logger.warn(self, "Session count: #{@sessions.size}")
  end

  @metrics.session_count.set(@sessions.size)
end

#close ⇒ Object 



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# File 'lib/mayu/server/app.rb', line 70

def close
  @barrier.wait
end

#get_session(id, request, resume: false) ⇒ Object 



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# File 'lib/mayu/server/app.rb', line 105

def get_session(id, request, resume: false)
  session = load_session(id, resume ? request.read.to_s : "")
  cookie_value = get_token_cookie_value(request)

  if session.authorized?(cookie_value)
    session
  else
    raise Errors::UnauthorizedSessionCookie,
          "session with id #{id} had wrong value #{cookie_value.inspect}"
  end
end

#handle_request(request) ⇒ Object 



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# File 'lib/mayu/server/app.rb', line 122

def handle_request(request)
  # FIXME: raise_if_shutting_down! should only prevent the following:
  # * starting new sessions
  # * updating sessions that have been transferred
  # * updating sessions that have been paused for transferring
  raise_if_shutting_down!

  case request.path.delete_prefix("/").split("/")
  in ["__mayu", "session", NANOID_RE => session_id, *rest]
    handle_session_post(request, session_id, rest)
  in ["index.js"]
    body = File.read(File.join(__dir__, "client", "dist", "live.js"))
    Protocol::HTTP::Response[
      200,
      { "content-type": "application/javascript" },
      [body]
    ]
  in ["robots.txt"]
    Protocol::HTTP::Response[
      200,
      { "content-type" => "text/plain; charset=utf-8" },
      File.read(File.join(@environment.root, "app", "robots.txt"))
    ]
  in ["favicon.ico"]
    # Idea: Maybe it would be possible to create
    # an asset from the favicon and redirect to the asset?
    Protocol::HTTP::Response[
      200,
      { "content-type" => "image/png" },
      Protocol::HTTP::Body::File.open(
        File.join(@environment.root, "app", "favicon.png")
      )
    ]
  in ["__mayu", "status"]
    Protocol::HTTP::Response[200, {}, "ok"]
  in ["__mayu", "runtime", *path]
    accept_encodings = request.headers["accept-encoding"].to_s.split(", ")

    filename = File.join(*path)

    if filename == "entries.json"
      return Protocol::HTTP::Response[403, {}, ["forbidden"]]
    end

    @runtime_assets.serve(filename, accept_encodings:)
  in ["__mayu", "static", filename]
    if @environment.config.server.generate_assets
      begin
        @environment.resources.wait_for_asset(
          filename,
          timeout: DEV_ASSETS_TIMEOUT_SECONDS
        )
      rescue Async::TimeoutError => e
        Console.logger.warn(
          self,
          "Asset #{filename} could not be generated in time"
        )
        return(
          Protocol::HTTP::Response[
            503,
            { "retry-after" => DEV_ASSETS_RETRY_AFTER_SECONDS },
            ["asset could not be generated in time"]
          ]
        )
      end
    end

    accept_encodings = request.headers["accept-encoding"].to_s.split(", ")

    @static_assets.serve(filename, accept_encodings:)
  in ["__mayu", *]
    raise Errors::FileNotFound,
          "Resource not found at: #{request.method} #{request.path}"
  in [*] if request.method == "GET"
    raise_if_shutting_down!

    handle_session_init(request)
  else
    Protocol::HTTP::Response[404, {}, ["not found"]]
  end
end

#handle_session_init(request) ⇒ Object 



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# File 'lib/mayu/server/app.rb', line 292

def handle_session_init(request)
  Console.logger.info(self) { "Init session: #{request.path}" }

  validate_header!(
    request.headers,
    "sec-fetch-mode",
    "navigate"
  ) do |value|
    raise Errors::InvalidSecFetchHeader,
          "Expected sec-fetch-mode to equal navigate but got #{value.inspect}"
  end

  validate_header!(
    request.headers,
    "sec-fetch-dest",
    "document"
  ) do |value|
    raise Errors::InvalidSecFetchHeader,
          "Expected sec-fetch-dest to equal document but got #{value.inspect}"
  end

  session =
    Session.new(
      environment: @environment,
      path: request.path,
      headers: request.headers.to_h.freeze
    )
  body = Async::HTTP::Body::Writable.new

  headers = {
    "content-type" => "text/html; charset=utf-8",
    "cache" => "no-cache"
  }

  accept_encodings = request.headers["accept-encoding"].to_s.split(", ")

  writer =
    if accept_encodings.include?("br")
      headers["content-encoding"] = "br"
      Brotli::Writer.new(body)
    else
      body
    end

  session.initial_render(writer) => { stylesheets: }

  headers["link"] = [
    "</__mayu/runtime/#{@environment.init_js}##{session.id}>; rel=preload; as=script; crossorigin=same-origin; fetchpriority=high",
    *stylesheets.map { "<#{_1}>; rel=preload; as=style" }
  ].join(", ")

  headers["set-cookie"] = set_token_cookie_value(session)

  @sessions.store(session.id, session)

  @environment.metrics.session_init_count.increment()

  Protocol::HTTP::Response[200, headers, body]
end

#handle_session_post(request, session_id, path) ⇒ Object

Raises:



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# File 'lib/mayu/server/app.rb', line 216

def handle_session_post(request, session_id, path)
  raise Errors::InvalidMethod unless request.method == "POST"

  if ["resume"] === path
    body = Async::HTTP::Body::Writable.new
    session = get_session(session_id, request, resume: true)
    run_event_stream(session, body:)

    return(
      Protocol::HTTP::Response[
        200,
        { "content-type": MIME_TYPES[:eventstream] },
        body
      ]
    )
  end

  session = get_session(session_id, request, resume: false)
  session.activity!

  case path
  in ["init"]
    body = Async::HTTP::Body::Writable.new
    run_event_stream(session, body:)
    Protocol::HTTP::Response[
      200,
      { "content-type": MIME_TYPES[:eventstream] },
      body
    ]
  in ["ping"]
    body = JSON.parse(request.read.to_s)
    pong = body["pong"].to_f
    ping = body["ping"]
    time = time_ping_value
    server_pong = time_ping_value - body["pong"].to_f
    headers = {
      "content-type": "application/json",
      "set-cookie": set_token_cookie_value(session)
    }
    session.log.push(
      :pong,
      pong: ping,
      server: server_pong,
      region: @environment.config.instance.region,
      instance: @environment.config.instance.alloc_id.split("-", 2).first
    )
    Protocol::HTTP::Response[200, headers, [JSON.generate(ping)]]
  in ["navigate"]
    @environment.metrics.session_navigate_count.increment()
    path = request.read.force_encoding("utf-8")
    session.handle_callback("navigate", { path: })
    headers = {
      "content-type": "text/plain",
      "set-cookie": set_token_cookie_value(session),
      "x-request-time": request.headers["x-request-time"]
    }
    Protocol::HTTP::Response[200, headers, ["ok"]]
  in ["callback", String => callback_id]
    session.handle_callback(
      callback_id,
      JSON.parse(request.read, symbolize_names: true)
    )
    headers = {
      "content-type": "text/plain",
      "set-cookie": set_token_cookie_value(session),
      "x-request-time": request.headers["x-request-time"]
    }
    Protocol::HTTP::Response[200, headers, ["ok"]]
  end
end

#raise_if_shutting_down! ⇒ Object

Raises:



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# File 'lib/mayu/server/app.rb', line 205

def raise_if_shutting_down!
  raise Errors::ServerIsShuttingDown if @stop.resolved?
end

#rerender ⇒ Object 



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# File 'lib/mayu/server/app.rb', line 94

def rerender
  @sessions.values.each(&:rerender)
end

#run_event_stream(session, body:) ⇒ Object 



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# File 'lib/mayu/server/app.rb', line 357

def run_event_stream(session, body:)
  @barrier.async do |task|
    session.activity!

    stream = EventStream::Writable.new(body)

    Console.logger.info(self, "Streaming events to session #{session.id}")

    barrier = Async::Barrier.new
    stop_notification = Async::Notification.new

    task.async do
      @stop.wait
      stop_notification.signal
    end

    session_task =
      barrier.async do
        session
          .run do |message|
            case message
            in [event, payload]
              session.log.push(:"session.#{event}", payload)
            end
          end
          .wait
      ensure
        stop_notification.signal
      end

    ping_task =
      barrier.async do
        loop do
          sleep PING_INTERVAL
          session.log.push(:ping, time_ping_value)
        end
      end

    message_task =
      barrier.async do |subtask|
        loop { stream.write(session.log.pop.to_a) }
      ensure
        barrier.stop
      end

    stop_notification.wait

    barrier.stop
    perform_transfer(session, stream)
    task.stop
  end
end

#stop ⇒ Object 



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# File 'lib/mayu/server/app.rb', line 63

def stop
  @stop.resolve(true)
  @barrier.wait
  Console.logger.info(self, "Stopped sessions")
end

#time_ping_value ⇒ Object 



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# File 'lib/mayu/server/app.rb', line 75

def time_ping_value
  Process.clock_gettime(Process::CLOCK_MONOTONIC, :millisecond).to_i &
    0x0fffffff
end