Class: ActionDispatch::ShowExceptions

Inherits:
Object
  • Object
show all
Defined in:
actionpack/lib/action_dispatch/middleware/show_exceptions.rb

Overview

# 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`, 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.

Instance Method Summary collapse

Constructor Details

#initialize(app, exceptions_app) ⇒ ShowExceptions

Returns a new instance of ShowExceptions.



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# File 'actionpack/lib/action_dispatch/middleware/show_exceptions.rb', line 26

def initialize(app, exceptions_app)
  @app = app
  @exceptions_app = exceptions_app
end

Instance Method Details

#call(env) ⇒ Object 



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# 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