class ActionDispatch::ShowExceptions
This middleware rescues any exception returned by the application and calls an exceptions app that will wrap it in a format for the end user.
The exceptions app should be passed as parameter on initialization of ShowExceptions
. Every time there is an exception, ShowExceptions
will store the exception in env, rewrite the PATH_INFO to the exception status code and call the Rack
app.
If the application returns a “X-Cascade” pass response, this middleware will send an empty response as result with the correct status code. If any exception happens inside the exceptions app, this middleware catches the exceptions and returns a FAILSAFE_RESPONSE
.
Constants
- FAILSAFE_RESPONSE
Public Class Methods
new(app, exceptions_app)
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# File lib/action_dispatch/middleware/show_exceptions.rb, line 26 def initialize(app, exceptions_app) @app = app @exceptions_app = exceptions_app end
Public Instance Methods
call(env)
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# File lib/action_dispatch/middleware/show_exceptions.rb, line 31 def call(env) request = ActionDispatch::Request.new env @app.call(env) rescue Exception => exception if request.show_exceptions? render_exception(request, exception) else raise exception end end
Private Instance Methods
pass_response(status)
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# File lib/action_dispatch/middleware/show_exceptions.rb, line 59 def pass_response(status) [status, { "Content-Type" => "text/html; charset=#{Response.default_charset}", "Content-Length" => "0" }, []] end
render_exception(request, exception)
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# File lib/action_dispatch/middleware/show_exceptions.rb, line 43 def render_exception(request, exception) backtrace_cleaner = request.get_header "action_dispatch.backtrace_cleaner" wrapper = ExceptionWrapper.new(backtrace_cleaner, exception) status = wrapper.status_code request.set_header "action_dispatch.exception", wrapper.unwrapped_exception request.set_header "action_dispatch.original_path", request.path_info request.set_header "action_dispatch.original_request_method", request.raw_request_method request.path_info = "/#{status}" request.request_method = "GET" response = @exceptions_app.call(request.env) response[1]["X-Cascade"] == "pass" ? pass_response(status) : response rescue Exception => failsafe_error $stderr.puts "Error during failsafe response: #{failsafe_error}\n #{failsafe_error.backtrace * "\n "}" FAILSAFE_RESPONSE end