#Undefined method map rails how to

If this is the case, the errors will look like this: ActionController::RoutingError (No route matches '///assets/application-eff78fd93759795a7be3aa21209b0bd2.css'): There is one common reason you might get an ActionController::RoutingError that is caused by your application and not by errant users: if you deploy your application to Heroku, or any platform that doesn’t allow you to serve static files, then you might find that your CSS and JavaScript doesn’t load. If that’s the case, you might find something like this in your logs: ActionController::RoutingError (No route matches '/wp-admin'): It may also be a malicious user or bot testing your application for common weaknesses. It may be caused by incorrect links pointing at or from within your application. Rails will log this and it will look like an error, but for the most part it is not the fault of your application. An ActionController::RoutingError means that a user has requested a URL that doesn’t exist within your application. We start with a classic of any web application, the Rails version of the 404 error. We'll provide example solutions based on Rails 5, but if you’re still using Rails 4 they should point you in the right direction. Let’s dig in and take a look at the errors in a bit more detail to see what might cause them in your production application. You’ve probably noticed some familiar faces in there already. We intentionally looked at the number of projects so that high-volume customers wouldn't overwhelm the data set with errors that are not relevant to most readers.

To do this, we ranked errors by the number of projects experiencing them across different companies. We focused on the errors most likely to affect you and your users. This gives users a nice overview instead of an overwhelmingly big dump like you’d see in a log file. Basically, we group two errors if the second one is just a repeat of the first. We do this by grouping errors according to fingerprinting. Rollbar collects all the errors for each project and summarizes how many times each one occurred. If you avoid these 'gotchas,' it'll make you a better developer.īecause data is king, we collected, analyzed, and ranked the top 10 Ruby errors from Ruby on Rails applications.

#Undefined method map rails how to

We’re going to show you what causes them and how to prevent them from happening. To give back to our community of developers, we looked at our database of thousands of projects and found the top 10 errors in Ruby on Rails projects.