I'm a beginner to both ruby and rails, and using Rails 5.17 to develop a web app for a class.
Creating the empty Rails project was successful, but something is going wrong when creating a new controller. I generated a new controller named cars from the root of the project, which was successful. There was a file in app/controllers named cars_controller.rb which looks like this:
class CarsController < ApplicationController
end
I added a method to this file named hello that does nothing.
I then created a file named cars.html.erb in the app/views/layouts directory. This file is a basic page of html code.
In config/routes.rb, I added the following:
get '/cars', to:: 'cars_controller#hello'
resources: cars
After all of this, I ran rails server, and opened localhost:3000 in a browser. This brings up the normal Ruby on Rails welcome page.
But when I go to localhost:3000/cars, I get the following:
Routing Error
uninitialized constant CarsControllerController
I've tried changing the name of the cars_controller.rb file. I've tried changing the name of the class in the controller file from CarsController to Cars. I've tried many different routes in routes.rb. I finally tried uninstalling Rails 5.17 and installing Rails 5.13.
I'm very confused, and I'd be grateful for any advice I can get. Thanks in advance!
One of the great things about Rails is its preference for convention over configuration. However, for this to really benefit you, you need to stick to doing things “The Rails Way” rather than your own way, wherever possible.
In this case, start by getting rid of your custom get route, and just use resources :cars.
From the command line, run rake routes (you might be able to run rails routes on your rails version too) and see the routes that it has created for you.
Now, rename the method you added to your CarsController from hello to index.
Move your hello.html.erb file from app/views/layout to app/views/cars/index.html.erb.
Finally, start the rails server (rails start) and load the url http://localhost:3000/cars in your browser.
—-
Note that templates in app/views/layout have a special purpose. These are used to apply a general template to your views. Look up the use of layout within a controller for more details
I think you have an error in how you had defined your route - you don't need _controller.
Instead, try this:
get '/cars', to: 'cars#hello'
Also, keep in mind that in your cars directory you need the view: hello.html.erb
Related
I am new to programming in general, someone referred me to railstutorial.org.
Specs: I am working on a cloud9 IDE, as suggested in the tutorial.
Information: I am on 1.3 of the rails tutorial, which is setting the root route.
The problem was initially my route did not effect the server launch (root page was still ruby default, not to 'application#hello'). Here are the files that the tutorial said to edit.
routes.rb
Rails.application.routes.draw do
root to: 'application#hello'
end
application_controller.rb
class ApplicationController < ActionController::Base
protect_from_forgery with: :exception
def hello
render text: "Hello, world!"
end
end
There are a lot of comments that were defaulted into the files that I left out.
I have followed the instructions precisely. After I first had trouble, I thought I may have made an installation error, so I deleted my IDE and restarted, paying extreme attention to detail, especially versions.
I have tried $ rake routes, and my understanding it gives the message:
You don't have any routes defined!
That leads me to believe that the problem is the routes.rb file. I have tried changing the syntax to:
root to: 'application#hello'
I don't know a whole lot, such as how it would work using application, so I also tried:
root 'ApplicationController#hello'
and
root to: 'ApplicationController#hello'
These all result in the no routes defined message. I have no idea what is going on.
Thanks for any input or help!
You could try root 'application#hello' in your routes. Also, when starting out simple things like forgetting to save the file before trying things out on the browser can slip by; restarting the server takes care of a surprising number of foibles.
The rails documentation can also provide you a bit more information beyond the tutorial.
You probably want to move that action outside of the ApplicationController to another controller, but if you really insist, you can put this into your routes.rb:
get '/hello', to: 'application#hello', as: :hello
If you want the page to be the root, I would recommend creating a StaticPagesController and defining hello there, instead of putting it inside ApplicationController.
Here's what you can do:
Run rails g controller static_pages
Inside your StaticPagesController.rb, copy and paste your hello method that was inside ApplicationController.
Change the routes.rb to root 'static_pages#hello.
and you should have your desired result.
I've followed the same tutorial and I can say that the materials covered in the first two chapters are quite complicated at first if you are new to programming. It's only after you've done the entire tutorial that it will become clear to you how this routing thing (or any other details in these chapters for that matter) actually works.
However, since this idea of routing is very important, it's not a bad idea to understand how it works even if you are at an early stage in the tutorial.
The way you can create a route in rails is that you first specify a proper HTTP verb (GET, POST, PATCH, DELETE) with an appropriate path, the name of a controller, followed by a hash sign (#) and the name of an action defined in the controller.
Here controller is just a ruby class and an action a ruby method. (Since the basic principle of ruby on rails is "convention over configuration", it's important to get used to the terminology like controller, action, routing etc...)
When you say
get '/hello' => "application#hello"
(yes, you can use => in place of to:) as takeriho suggests, what happens is that a GET request to a URL of the type /hello(/ being "root path" as in www.example.com/(note the / at the end)) will get routed to the action, or method, named hello defined in a controller, or a class, named ApplicationController.
If you take a look at application_controller.rb, you can see that a method hello is defined within a class ApplicationController.
class ApplicationController < ActionController::Base
.....
def hello
render text: "Hello, world!"
end
end
Now if you want to specify a root route, which is your original question, you can just do root followed by the name of a controller, a hash sign (#), and the name of a class. So the code
root "application#hello"
means that a request to a url of the form /, or a root_path as it's called in rails convention, will get routed to the action (or method) named hello defined in a controller (or a class) named ApplicationController. You could accomplish the same result by doing
get '/' => "application#hello", as: :root
(you can name a route by adding as: :custom_name) but rails is smart enough to know that the two are equivalent. The task is made easier by following the rails conventions.
If you are completely new to Rails, I highly suggest you check out the Rails courses in Pragmatic Studio before going through the Ruby on Rails Tutorial which, as the author suggests, is not for a complete beginner. This approach worked perfectly for me. The rails courses offered by Pragmatic Studio assumes you have no prior knowledge about programming, and explains the basics in a manner much clearer than I did in this answer.
Happy coding :)
Just wanted to know, what does this line mean in the routes.rb file:
AppName::Application.routes.draw do
Please explain. I am new to Rails.
Have a read through this page.
Basically, within the block passed to Application.routes.draw (which is just a call to a method defined in ActionDispatch::Routing module within the Rails core framework), you define all the URLs/Paths that you want your Rails application to respond to.
You can see all these route definitions, by running:
rake routes
in your terminal.
It is the main routes file which defines the root and other paths for the link.
It is used as suppose you want to change your index page from default ruby on rails to your index page you make changes to file and add
root to: "controllername#index"
This file is also used to add the model to the application
resources: "model_name"
Apart from this you can also define links in your rails application
get 'courses/index'
So going from courses controller to view of the index.
I'm very new to RoR and I'm trying to get a very basic site going. I have my home page working okay, but when I try to add a new page, I keep getting "No route matches" in the log. Here is the output from rake routes:
Prefix Verb URI Pattern Controller#Action
inventing_index GET /inventing/index(.:format) inventing#index
ideas_index GET /ideas/index(.:format) ideas#index
root GET / ideas#index
However, when I go to mysite.com/inventing or mysite.com/inventing/index I get the no route matches error. mysite.com/ shows the app/views/ideas.erb as hoped. All I did was rails generate controller inventing index. Is there something else I have to do to activate the route?
I'm running ruby 2.0.0p247 and rails 4.0.0 with passenger/apache on centos 6. I installed all the ruby/rails/passenger stuff, so its possible something isn't setup properly.
Thanks
EDIT: Here is my routes.db file:
Rortest::Application.routes.draw do
get "inventing/index"
get "ideas/index"
root to: 'ideas#index'
end
tldr: Your problem is probably the route. Change get 'inventing/index' to get 'inventing/index'=> 'inventings#index' to correctly point the route to your controller action.
There are four things you need to do when adding a new page/route. I usually do them in this order for static pages:
1) Create a controller with the appropriate action for each page
You already did this with rails generate controller inventing index, but make sure that:
In your app/controllers folder, you do indeed have a file called inventings_controller.rb
In inventings_controller.rb, you have at least this:
class InventingsController < ApplicationController
def index
end
end
2) Create a view for each controller action
Make sure that:
In your app/views/inventings folder, you have a file called index.html.erb
Puts some simple HTML in that file, like <h1>Testing123</h1>, just so you can see if it's working.
3) Add a route for each controller action
It looks like this may be the problem. In your routes.rb file, you'll need this:
get 'inventing/index' => 'inventings#index'
Your root to works because it's actually pointing directly to your controller action, but rails isn't smart enough to guess that inventing/index should go to the index action in your inventing**s** controller.
4) As others have suggested, restart your rails app
You can do this with ctrl+c at the command line, then rails s again to start it back up.
I'm new to Ruby on Rails and am doing my first tutorial and am running the latest version of rails 3 and ruby 1.9.2. After creating my controller and navigating to http://localhost:3000/say/hello I'm receiving a blank page. I do see the Welcome to Rails message when I just go to http://localhost:3000. I've done some Google searches and people have similar problems but there is no clear fix. I've never really worked with MVC before so the concept of routing is fairly new to me.
Below is my controller:
class SayController < ApplicationController
def hello
end
def goodbye
end
end
My view:
<h1>Say hello to Rails!</h1>
You should delete the public/index.html file as that will mess with your routing and display by default. Have you set up your routes already, and what is the exact location and filename of the template?
You will need something like in your config/routes.rb file to correctly route that url to your template/view:
match '/say/hello' => 'say#hello'
First delete the index.html file from your public folder. Then, go to the app/views and check the views for the say controller. You should have a hello.html.erb.
The answer to your particular question was answered already by Bitterzoet, but I thought you might want some alternative learning resources.
I'm not sure which tutorial you're starting with, but I find it odd that they're not using RESTful routes. You can find out what routes you have set up at the moment by going to the console and typing "rake routes". If you would like a different tutorial, I recommend the one here:
http://www.wiki.devchix.com/index.php?title=Rails_3_Curriculum
I'd also recommend http://railsforzombies.org/ as a good first-time rails experience.
A fun general line to add to config/routes is:
match ':controller(/:action(/:id(.:format)))'
While developing, this will allow you to display the controller/action in address bar for ALL controller/action/id.format etc.
Like Bitterzote wrote, if controller is "say" and action is "hello", http://localhost:3000/say/hello .
If you use controller "say" and action "move", http://localhost:3000/say/move .
I've found this route to be very useful during development, but change this if you launch your application! (Rails warns: "Note: This route will make all actions in every controller accessible via GET requests.")
I created a controller and a model. The controller is called "Admin" and the model is called "Album". I edited database.yml with proper info and did the rake db:migrate command which didn't return any errors and did migrate the db inside schema.rb. Inside the controller I wrote:
class AdminController < ApplicationController
scaffold :album
end
Next I started my server and went to http://localhost:3000/admin but instead of seeing the typical CRUD page I get the following error:
app/controllers/admin_controller.rb:3
Request
Parameters:
None
Show session dump
---
flash: !map:ActionController::Flash::FlashHash
{}
Response
Headers:
{"cookie"=>[],
"Cache-Control"=>"no-cache"}
Any idea why?
That syntax for scaffolding has been deprecated for quite some time. Nowadays, rails (versions 2.x) use the following method to scaffold a resource:
script/generate scaffold Album title:string date:date ...
That generates the scaffolding views (in app/views), the controller (app/controllers), standard tests (in test/) and, crucially, the required routes to make scaffolding work.
I believe the rails dev team took away the old syntax ("scaffold :resource") because no real application would ever leave a scaffold untouched, ie. you will always need some kind of customization. With the new syntax you can leave it untouched, but it is also much easier to customize.
If you really need your controller to be named admins, you can change the file config/routes.rb after generating the scaffolding. It makes no sense, though: Why should the URI to create a new album be called "/admins/new"?
If you are trying to create an admin area for an image album app, you are probably looking for namespaces (so you can have multiple different resources, controllers and views inside the "admin" namespace). To create an album resource within the admin namespace, write:
script/generate scaffold Admin/Album title:string date:date
In that case, your controller will be accessible as http://host/admin/albums.
Hm,
Normally you would have a controller and a model called Admin and the same thing would be about Album,
Take a look at this quick screen cast how a blog is done using scaffolding;
Creating a web-blog
the script/generate command seems not to work, someone has to provide ./script/generate , I think its a linux directory issue, you have to explicitly say you are starting from the current directory (./). hope this helps someone avoid scratching his head