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. Everytime 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.

Methods
C
N
R
Constants
FAILSAFE_RESPONSE = [500, {'Content-Type' => 'text/html'}, ["<html><body><h1>500 Internal Server Error</h1>" << "If you are the administrator of this website, then please read this web " << "application's log file and/or the web server's log file to find out what " << "went wrong.</body></html>"]]
Class Public methods
new(app, exceptions_app = nil)

Source: show | on GitHub 

    # File actionpack/lib/action_dispatch/middleware/show_exceptions.rb, line 39
39:     def initialize(app, exceptions_app = nil)
40:       if [true, false].include?(exceptions_app)
41:         ActiveSupport::Deprecation.warn "Passing consider_all_requests_local option to ActionDispatch::ShowExceptions middleware no longer works"
42:         exceptions_app = nil
43:       end
44: 
45:       if exceptions_app.nil?
46:         raise ArgumentError, "You need to pass an exceptions_app when initializing ActionDispatch::ShowExceptions. " \
47:           "In case you want to render pages from a public path, you can use ActionDispatch::PublicExceptions.new('path/to/public')"
48:       end
49: 
50:       @app = app
51:       @exceptions_app = exceptions_app
52:     end
rescue_responses()

Source: show | on GitHub 

    # File actionpack/lib/action_dispatch/middleware/show_exceptions.rb, line 26
26:       def rescue_responses
27:         ActiveSupport::Deprecation.warn "ActionDispatch::ShowExceptions.rescue_responses is deprecated. " \
28:           "Please configure your exceptions using a railtie or in your application config instead."
29:         ExceptionWrapper.rescue_responses
30:       end
rescue_templates()

Source: show | on GitHub 

    # File actionpack/lib/action_dispatch/middleware/show_exceptions.rb, line 32
32:       def rescue_templates
33:         ActiveSupport::Deprecation.warn "ActionDispatch::ShowExceptions.rescue_templates is deprecated. " \
34:           "Please configure your exceptions using a railtie or in your application config instead."
35:         ExceptionWrapper.rescue_templates
36:       end
Instance Public methods
call(env)

Source: show | on GitHub 

    # File actionpack/lib/action_dispatch/middleware/show_exceptions.rb, line 54
54:     def call(env)
55:       begin
56:         response  = @app.call(env)
57:       rescue Exception => exception
58:         raise exception if env['action_dispatch.show_exceptions'] == false
59:       end
60: 
61:       response || render_exception(env, exception)
62:     end