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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.

Methods
C
N

Class Public methods

new(app, exceptions_app)

Source: show 

# File actionpack/lib/action_dispatch/middleware/show_exceptions.rb, line 25
def initialize(app, exceptions_app)
  @app = app
  @exceptions_app = exceptions_app
end

Instance Public methods

call(env)

Source: show 

# File actionpack/lib/action_dispatch/middleware/show_exceptions.rb, line 30
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)
  if wrapper.show?(request)
    render_exception(request, wrapper)
  else
    raise exception
  end
end