Action Dispatch 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 a parameter on initialization of ShowExceptions
. Every time there is an exception, ShowExceptions
will store the exception in env["action_dispatch.exception"]
, rewrite the PATH_INFO
to the exception status code, and call the Rack app.
In Rails
applications, the exceptions app can be configured with config.exceptions_app
, which defaults to ActionDispatch::PublicExceptions
.
If the application returns a response with the X-Cascade
header set to "pass"
, this middleware will send an empty response as a result with the correct status code. If any exception happens inside the exceptions app, this middleware catches the exceptions and returns a failsafe response.
Class Public methods
new(app, exceptions_app) Link
Instance Public methods
call(env) Link
# File actionpack/lib/action_dispatch/middleware/show_exceptions.rb, line 31 def call(env) @app.call(env) rescue Exception => exception request = ActionDispatch::Request.new env backtrace_cleaner = request.get_header("action_dispatch.backtrace_cleaner") wrapper = ExceptionWrapper.new(backtrace_cleaner, exception) request.set_header "action_dispatch.exception", wrapper.unwrapped_exception request.set_header "action_dispatch.report_exception", !wrapper.rescue_response? if wrapper.show?(request) render_exception(request.dup, wrapper) else raise exception end end