Where can I register a handler in Rails 3 that can catch view errors? There is a class of error that Rails raises that we wish to handle and silence instead of logging as FATAL.
(These are not errors in our code, rather errors caused by the client closing the connection before the page has finished rendering, and Rails/unicorn attempting to write to a broken pipe.)
Will rescue_from work for you? http://api.rubyonrails.org/classes/ActiveSupport/Rescuable/ClassMethods.html
You can conceivably rescue (and silence) your particular subclass of ActionView::TemplateError
Related
My app is just a typical Rails with a Postgresql (actually, Postgres app on OS X). I would like to add exception handling when my Rails app cannot connect to the database and show plain text of connection error for now, instead of a Rails error page (or may be static HTML error page later on).
I've tried adding exception below to the application_controller.rb.
# from app/controllers/application_controllers.rb
-------------------------------------------------
rescue_from PG::ConnectionBad, with: :database_connection_error
def :database_connection_error
render plain: "Could not connect to the Database"
end
(code ommited)
but it's not rendering plain text. (I also use this exception snippet on the other controllers. It's working but it's handling a different exception, e.g. I use it to handling ActiveRecord::RecordNotFound error)
Is there any way to handle a PG::ConnectionBad or point out what I am doing wrong here?
Thanks in advance.
I just launched a completely rebuilt in rails website and am using New Relic for error monitoring. I've been getting a lot of errors and alerts for what I'm guessing is people using bookmarks for pages/paths that no longer exist and possibly some hot linking.
What is the best way to resolve this situation so that I stop getting the alerts?
How about ignoring those errors?
ignore_errors - A comma separated list of Exception classes which will
be ignored
In addition, the error collector can be customized programmatically
for more control over filtering. In your application initialization,
you can register a block with the Agent to be called when an error is
detected. The block should return the error to record, or nil if the
error is to be ignored. For example:
config.after_initialize do
::NewRelic::Agent.ignore_error_filter do |error|
if error.message =~ /gateway down/
nil
elsif
error.class.name == "InvalidLicenseException"
StandardError.new "We should never see this..."
else
error
end
end
end
(source)
I've got problem with migrating rails 2.x -> 3.2.13
At some point, after fixing a few things, I get Completed 500 Internal Server Error in 76ms without any traceback.
development.rb
config.consider_all_requests_local = true
config.action_controller.perform_caching = false
Why there is no traceback and how to fix this?
you probably solved it but I wanted to share my couple of hours debugging about this issue as it can be very annoying. In short, I was having the same problem - 500 internal server error without any log of the exception thrown. It was happening only for exceptions thrown in the action view templates - any ActionView::Template::Error exception. For example, missing partial, invalid route.
My specific problem was using this ruby statistics module:
http://derrick.pallas.us/ruby-stats/
directly in the initializers directory which works great in rails 2.x. It defined Array.sum method which is already defined in rails 3 under Enumerable.sum. The problem with the redefine is that Array.sum no longer works with arrays of strings which is what rails was trying to do with ActionView::Template::Error.source_extract method - when trying to extract the source of the error in template, it uses the Enumerable.sum method which is redefined in a wrong way. Thus, another exception happened TypeError: cannot convert String into Fixnum and the original exception was not logged, neither was the new one. I had to do a backtrace and go through many of the internal calls to see where is the issue.
So, for everyone not seeing the actual exceptions thrown in your ActionView templates, check if you have not redefined a rails method that is used internally in rails.
How can I use exception handling in Rails? Currently I have done following.
In each controller method I have added
begin
<myCode>
rescue
<exception handler>
But I think with Rails I should be able to define an exception handler method in Application controller and catch all the exceptions from there, without handling them from each method.
I have used 'rescue_action_in_public' in my application controller, but when I given a wrong database name in config/database.yml and load the application, it doesn't catch those exceptions.
My questions are
1 - Is it a recompilation practice to have one exception handler in the application controller and catch the exceptions ? If not, what is the standard way ?
2 - How can I handle the Exceptions like Databse not found, doesn't have permission to view table fields, etc kind of low level exceptions
I'm riding on Rails 3 and I have some projects in Rails 2.3.8 as well
With according to Advanced Rails Recipes book by PragProg, the general exception handling is the good approach.
rescue_action (all environments), and rescue_action_in_public (production) are using to caught any exceptions in abstract controller class. So you do it right way.
Boot application happens before the controllers are loaded, so you can't handle database.yml over there. If you still need to do it, put an initializer ruby file to check that the file exist and a valid, then initialize AR::Base connection to perform DESC table for instance.
For Rails 3 you can use rescue_from in your ApplicationController. If the exceptions you want to catch are at a lower level then you can configure a Rack Middleware layer will allow you to catch exceptions that the controller does not have access to. This is how Hoptoad works. I recently released a rails 3 gem that will catch common exceptions using rescue_from and provide well defined http status codes and error responses for html, json and xml. This may or may not fit your needs. https://github.com/voomify/egregious
I created a webpage and a XML REST service.
0.
I would like to know how errors are handled in Rails (general).
1.
Let say that a controller does not exists and I would like to redirect a user to a default "Page not found" address (website) or show a default error status code (REST).
2.
What is a best practice for handling controller action errors e.g. when saving but a record is not saved or some param[] field does not exists or else. Usually I use rescue command and I repeat this in every create or update action (would be cool to have some kind of general error handling for that case).
Thank you!
Rails handles 404 and 500 errors out-of-the-box. In development mode you will see detailed error messages. However, in production Rails will use the 404.html and 500.html pages in the public directory.
If the route is not recognised, Rails will return a 404 error.
I generally don't handle errors at the controller level unless they are expected - so I don't wrap everything in begin...rescue. Rails will return the 500 error page if something fatal has occurred. If I expect a particular set of parameters I validate before proceeding and in this case have a redirection or return result to indicate the incomplete parameters.