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
Class Public methods
new(app, exceptions_app)
📝 Source code
# File actionpack/lib/action_dispatch/middleware/show_exceptions.rb, line 26
def initialize(app, exceptions_app)
@app = app
@exceptions_app = exceptions_app
endInstance Public methods
call(env)
📝 Source code
# 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