Hey there! Welcome to homework 2 of the Rails DeCal. By this week, the course will have covered routes, simple ruby syntax, and basic CRUD statements.
As you complete this homework, refresh your browser to observe changes you expect. If that doesn't work, try restarting the server.
Per usual, Google and Stack Overflow are your best friends when debugging.
To start everything off, fork this repository - there should be a fork button on the top right corner of the repo.
After you fork, run these commands to clone your newly forked repository:
git clone https://github.com/your_username/fa16-hw2
cd fa16-hw2
Next, install all the gems (Rails libraries) necessary by running:
bundle install
Then, start your server by running:
rails server
Try going to localhost:3000 in your browser. But wait...it's broken. What's going on? Routes? Undefined?
If you take a look at a couple of the classes in the app/controllers/concerns/ directory, you'll see some weird functions - attr_accessor and initialize.
initialize is similar to Python's __init__ method and is called every time you create a new object. If you do not define an initialize method, Ruby will just assume that your class has an empty initializor.
attr_accessor is used to define instance variables so that you can have both read access (via your_class.instance_variable) and edit access (via your_class.instance_variable = some_value). Ruby allows you to forbid edit or read access using attr_readable and attr_writer, respectively.
Also, you'll see a lot of <%= some_variable %>. This is embedded ruby, which we'll be covering next week.
Here, we're going to look into a POST request.
If you look closely at the code at home.html.erb, you'll see a bunch of confusing code like this:
<%= form_tag stringify_path do... %>
Don't worry if this is confusing to you. We'll be covering forms in the future. What is important is that a form POSTs a request to a endpoint/path.
To fix the errors, route a path in the routes.rb file so that a POST request to localhost:3000 (also known as the root) routes to the stringify method in pages_controller.rb.
Now that we've gone through that hassle, we now face our second problem. If you try to submit the form, you get a views error message (missing template pages/stringify)!
To fix this, update app/controllers/concerns/stringify such that the what_am_i method returns "You are nothing!" if @name or @adjective are blank, but returns "your_name is so your_adjective" if @name and @adjective are not blank.
Hint: The method blank? may be helpful.
Following, create a stringify.html.erb view and add
<%= @text %>
to the view (where should this file go?). Now when you submit the form, nothing should error and you should see the result of your what_am_i method.
If you take a look in the app/controller/concerns/ directory, you'll see that we've defined a class for you called Foobar. This is where we'll be spending some time to practice Ruby!
If you take a look at pages_controller.rb, we have two commented lines of code:
# foo = Foobar.new "baz"
# @baz = foo.bar :cat, sat: :dat, dat: :sat
Write an initialize method and an instance method bar in Foobar so that when you uncomment the code in pages_controller.rb, the home page will render the string "catbazdat" under "Your result". Do not hard code any strings; use the values passed into the bar method and the initializer.
Uncomment the code in pages_controller.rb and validate your changes.
Now we're going to look at more routing + creating classes!
If you look at the Question 3 section on the home page, you'll see that we have another form! However, if you submit it you'll get an error message telling you that no route matches the request.
Let's fix this bug.
Step 1: <%= form_tag age_path, method: :put do %> tells Rails to create a PUT request to /age on form submission. Create an appropriate route in routes.rb to handle the form submission; direct it to the person method in pages_controller.rb, rather than the age method. This means that a GET request to /age will be handled by a different action than a PUT request to /age!
Step 2: in /controllers/concerns, implement a Person class whose initialize method accepts a name and age and creates an instance variable @nickname that is the first four letters of @name.
The Person class should have the following methods:
introduce: returns a string with the instance's name and agebirth_year: calculates what year they were born given an age in yearsnickname: returns the nicknamefib_number: returns the@age-th fib number (ex: if I am 21, return the 21th fib number).
Submit the Question 3 form (which will direct you to localhost:3000/age) and validate you did this correctly.
Note: don't worry about blank form edge cases (which we practiced handling before) and formatting.
Let's practice some HTML/CSS:
Create a view that can be seen if you go to localhost:3000/me. Just a friendly reminder, to do this you'll have to create a route, a controller action, and a view.
In this view, render your name, a picture of yourself (upload your file into assets/images), where you're from (give it a green background with white text), your year (freshman/sophomore/junior/senior/etc), a fun fact (make the text bold and red!), and what you're most excited about in this class (make the text underlined and change the color to anything you want!)
Go to localhost:3000/me and validate you did this correctly.
You're done! Whew. Time to submit! Run these commands:
git add .
git commit -am "whatever message you want"
git push origin master
Fill out the submission form for this homework, which can be found on Piazza.