defmodule Plug.Adapters.Cowboy.Handler do
@moduledoc false
@connection Plug.Adapters.Cowboy.Conn
@already_sent {:plug_conn, :sent}
def init({transport, :http}, req, {plug, opts}) when transport in [:tcp, :ssl] do
{:upgrade, :protocol, __MODULE__, req, {transport, plug, opts}}
end
def upgrade(req, env, __MODULE__, {transport, plug, opts}) do
conn = @connection.conn(req, transport)
try do
%{adapter: {@connection, req}} =
conn
|> plug.call(opts)
|> maybe_send(plug)
{:ok, req, [{:result, :ok} | env]}
catch
:error, value ->
stack = System.stacktrace()
exception = Exception.normalize(:error, value, stack)
reason = {{exception, stack}, {plug, :call, [conn, opts]}}
terminate(reason, req, stack)
:throw, value ->
stack = System.stacktrace()
reason = {{{:nocatch, value}, stack}, {plug, :call, [conn, opts]}}
terminate(reason, req, stack)
:exit, value ->
stack = System.stacktrace()
reason = {value, {plug, :call, [conn, opts]}}
terminate(reason, req, stack)
after
receive do
@already_sent -> :ok
after
0 -> :ok
end
end
end
defp maybe_send(%Plug.Conn{state: :unset}, _plug), do: raise Plug.Conn.NotSentError
defp maybe_send(%Plug.Conn{state: :set} = conn, _plug), do: Plug.Conn.send_resp(conn)
defp maybe_send(%Plug.Conn{} = conn, _plug), do: conn
defp maybe_send(other, plug) do
raise "Cowboy adapter expected #{inspect plug} to return Plug.Conn but got: #{inspect other}"
end
defp terminate(reason, req, stack) do
:cowboy_req.maybe_reply(stack, req)
exit(reason)
end
end