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Form and Route Helpers in Rails

Clone this repo, then bundle, run rake db:migrate, and open the code in your text editor.

Setup

  • open the console (rails c) and check how many articles already exist.
  • take a look at seeds.rb inside of the db folder. What is it doing? What would you expect to happen when you run rake db:seed?
  • exit the console and run rake db:seed
  • start up the rails console: rails c
  • check that you have three articles in the development database
> Article.count
   (0.1ms)  SELECT COUNT(*) FROM "articles"
 => 3
  • exit out of the rails console: exit

Experimenting with Route Helpers

  • Start your server with rails s.
  • Navigate to localhost:3000/articles. You should see each of the article titles as a link, in addition to a link for making a new article.
  • In your text editor, open up app/views/articles/index.html.erb. Right now, the code to make each individual article link looks like this:
  <a href="/articles/<%= article.id %>"><%= article.title %></a> <br>
  • This should look pretty similar to how you created links in TaskManager with Sinatra.
  • Can you replace this bit of code with a Rails route helper that provides the same behavior? Try using link_to, and check the Rails Guides for Path and URL Helpers here. This might also be a good opportunity to practice your Stack Overflow skills in trying to find examples and/or explanations :)
  • Can you replace the "Make a new article" link with another Rails route helper that leads to the form?
  • Can you add a link using a route helper on the show.html.erb page so that a user can get back to the articles index?
  • How is the prefix section from the output of running rake routes connected with route helpers?

Form Helpers

  • Open app/views/articles/new.html.erb and look at the uncommented form helper.
  • Navigate to localhost:3000/articles/new and use inspect code for the form (for example in Chrome: right-click on the form and choose "inspect element").
  • What does form_for(@article)... do? What HTML does it generate? Does this look familiar or foreign? What could would you have written to create the same thing in Sinatra?
  • Fill in a title and description in the input boxes. When you click submit on the form, an error should be raised (this is on purpose). That error will show you the params that are coming in:
{"utf8"=>"✓", "authenticity_token"=>"N1P3tOB7xGlU2GDXKV9tlVwmL2ZXKT3jiumxXNQYmTWl7xdK7X8SrU2z1jBt0/yiUxLkTOwK/r5a1l6+bc+uzg==", "article"=>{"title"=>"title", "body"=>"body"}, "commit"=>"Create Article", "controller"=>"articles", "action"=>"create"}

You'll see the keys of utf8, authenticity_token, commit, controller, and action, but ignore them for now and just focus on the article key.

  • How are the params nested? How would you access just the article data (title and description) from the params hash?
  • Go back to app/views/articles/new.html.erb. Comment out the first form and uncomment the second form. You'll need to manually take out or put in each # in the erb tags.
  • Repeat the steps above. How is form_tag different from form_for? Either StackOverflow this, look at the docs, or put a byebug in the controller and take a look at your params. What is different about the HTML that is generated? (use Chrome inspector to look at the HTML). Are the params nested? What implications might this have for using the params to create a new article?
  • Which do you think makes more sense for creating a new article: form_for(@article)... or form_tag articles_path? Why?

Want to read more about form helpers in Rails? Check out the docs.