remove env access from debug_exceptions

Creates fewer request objects and helps to abstract away from internals

actionpack/lib/action_dispatch/middleware/debug_exceptions.rb

@@ -55,18 +55,17 @@ def call(env)
       response
     rescue Exception => exception
       raise exception unless request.show_exceptions?
-      render_exception(env, exception)
+      render_exception(request, exception)
     end
 
     private
 
-    def render_exception(env, exception)
-      backtrace_cleaner = env['action_dispatch.backtrace_cleaner']
+    def render_exception(request, exception)
+      backtrace_cleaner = request.get_header('action_dispatch.backtrace_cleaner')
       wrapper = ExceptionWrapper.new(backtrace_cleaner, exception)
-      log_error(env, wrapper)
+      log_error(request, wrapper)
 
-      if env['action_dispatch.show_detailed_exceptions']
-        request = Request.new(env)
+      if request.get_header('action_dispatch.show_detailed_exceptions')
         traces = wrapper.traces
 
         trace_to_show = 'Application Trace'
@@ -108,8 +107,8 @@ def render(status, body, format)
       [status, {'Content-Type' => "#{format}; charset=#{Response.default_charset}", 'Content-Length' => body.bytesize.to_s}, [body]]
     end
 
-    def log_error(env, wrapper)
-      logger = logger(env)
+    def log_error(request, wrapper)
+      logger = logger(request)
       return unless logger
 
       exception = wrapper.exception
@@ -125,8 +124,8 @@ def log_error(env, wrapper)
       end
     end
 
-    def logger(env)
-      env['action_dispatch.logger'] || stderr_logger
+    def logger(request)
+      request.logger || stderr_logger
     end
 
     def stderr_logger