gmarriner-ddd/form-intro

Form Intro

Target

The username and password is on Canvas — here is our target:

https://form-intro.matchthetarget.com/

Query strings

The essential piece: add a query string onto any URL in your Rails app, e.g.

/rock?dessert=Ice cream&color=Orange

and watch what happens in your server log when you visit that URL.

Rails parses any query string parameters and puts them into a special Hash called params. You have access to params in the action.

With that simple fact, combined with the way that HTML forms behave, we can invent ways to make any forms we want work!

Your first task

Wire up the following 4 RCAVs and add <h1> elements to each that say "Addition", "Subtraction", "Multiplication", and "Division":

• /add
• /subtract
• /multiply
• /divide

Use the slides, chapter, and your RPS RCAV workspace as a reference.

Your second task

Visit your /add URL, but type a query string on to the end: ?first_num=3&second_num=4. So, the whole path should be:

/add?first_num=3&second_num=4

First pull up the Terminal tab running your server and Cmd-K or Ctrl-K to clear it out, then visit that URL again. Scroll to the top of the Terminal tab. Read the log — what do you notice?

The params Parameters Hash! Use the params hash in the action you defined to calculate a result and display it in the view template you created. Make the markup match the target.

Do the other 3

Do the same thing for

• /subtract,
• /multiply,
• and /divide.

Review form attributes

Remember when we reverse engineered HTML forms? Review and remind yourself what each attribute does — action, id, for, value, type, placeholder, name.

Add forms

Now, make it easier on your users. They should not have to type into the address bar of their browsers to access these useful calculations.

Can you invent a way to make it easier for them using what you've learned about RCAV, params, and what we reverse-engineered about how HTML forms work?

Google Cloud Translate

• Google Cloud Translation

Here's the crux of using the official gem:

Add the gem to your Gemfile:

# /Gemfile
gem "google-cloud-translate"

Then bundle install and restart your web server.

You now have access to the Google::Cloud::Translate class. To use it:

gt_client = Google::Cloud::Translate.new({ :version => :v2 })
translation = gt_client.translate("Hello, world!", { :to => "es" })

Amazing!

To list all available languages,

languages = gt_client.languages("en") # The argument determines what language to list the other language names in
languages.size #=> 104
languages[0].code #=> "af"
languages[0].name #=> "Afrikaans"

Read more at the gem docs:

• Ruby gem documentation