#memorizing code

Topics

Assessment 4 - Tuesday, 6/7/16

2 hour assessment

MVC & Authentication

HTML

ERB

Rails

Capybara/RSpec

Essentially, a memorization test where you can't use Google to help you debug, so you'd best memorize all of the possible bugs/solutions you may run into!

Common Errors & Possible Solutions

class User - don't forget these clutch lines

- after_initialize :ensure_session_token - attr_reader :password - @password = password; in def password=(password) method - self.save! in reset_token!

class UserController

User.new(user_params) in create method (not find(params[:id])

before_filter :require_logged_in - at top of LinksController

The following error message means you likely either wrote link_url when you should have written links_url, or forgot to pass in @link or link_id into link_url(@link)

“No route matches {:action=>”show”, :controller=>”links”} missing required keys: [:id]

Since link_url requires an :id or @link, get “missing required keys: [:id]” error message

Check action="__"

`` - only put at bottom of all pages (application.html.erb), in if/else logged_in? block. If you put it in individual pages as well as application.html.erb, Capybara will get confused and won't know which of the two buttons to press

save_and_open_page - put line in rspec, and Capybara will pop open the page in your browser.

Useful for seeing what Capybara is seeing

Can tell you when Capybara is ending up at the wrong page, so you need to fix a link (rather than checking an html.erb page)

If redirecting to wrong page, check action=“” is directing to correct url (especially since copying & pasting)

rails g model User username:string password_digest:string session_token:string

Will create both Migration file & Model file at the same time

Migration file with have column names pre-written, just have to add null: false, indexes, and unique: true constraints

rails g controller Link new create index show update destroy

Will create all controller actions & routes that you list, when creating Controller

Don't have to write def create / end for all of the different methods, faster

Flash.now[:errors] - only sets the lifecycle of an error message, but can still print them by iterating through flash[:errors]

Safer to just use flash[:errors] on this assessment, less likely to run into bugs

In general, should prioritize flash.now so errors don't persist needlessly

rails d controller “NameController” - delete controller & all associated files

Delete controller & associated files - in case you made a mistake

resource :session - in routes.rb, both "resource" and "session" should be singular

Capybara:ElementNotFound - most likely means Capybara is ending up in the wrong place, check destination_url of button/link you’re coming from

The following error crops up a lot:

Failure/Error: expect(response).to render_template("new") expecting but rendering with ActionView::Template::Error: No route matches {:action=>"show", :controller=>"links"} missing required keys: [:id]

My solution was to fix the destination_url in the button that was pointing to this view

<%= button_to "Sign Out", session_url, method: :delete %>

Not sure if this solves all circumstances

Unable to find field “URL"

Make sure input is labelled id="URL" since Capybara uses the id tag to change/update fields

Capybara is case sensitive

The following error may indicate that you swapped the order of require/permit in your strong_params

Failure/Error: click_button 'Add Comment' ArgumentError: wrong number of arguments (3 for 1)

Issue: params.permit(:comment).require(:body, :link_id, :user_id)

Correct code: params.require(:comment).permit(:body, :link_id, :user_id)

The following error cropped up when I was pre-filling value="" in session/new.html.erb

Failure/Error: click_button "Sign In" ActionView::Template::Error: undefined method `username' for nil:NilClass

The code worked when I removed the pre-filled in value, so a/A was not checking for the username to persist if user entered it incorrectly the first time

Another solution is to pass in @user = User.new({username: params[:user][:username]}) in the Session Controller's create method, in case they want incorrect username/passwords to persist

Files/code to memorize

user.rb - User Model

application_controller.rb - Application Controller

user_controller.rb - User Controller

session_controller.rb - Session Controller

new.html.erb - New User Form, can reference HTML code for other forms

The rest can be logic-ed through and pieced together from there, based on the project & specs

Incorrectly had before_action :require_logged_in in SessionController rather than LinksController

Failure/Error: post :create, user: {username: "jill_bruce", password: "abcdef"} RuntimeError: @controller is nil: make sure you set it in your test's setup method.

This errors also crops up when you mis-name the SessionsController as SessionController (singular). Must rename all controller & view files

Must pass in username as a hash in create action of session_controller.rb

Failure/Error: post :create, user: {username: "jack_bruce", password: "notmypassword"} ArgumentError: When assigning attributes, you must pass a hash as an argument.

@user = User.new({username: params[:user][:username]})

Use this line to guarantee that we can pre-fill username, but must be passed into User.new as a hash and not just a value

This error crops up when you forget to include the erb tag in action="___"

Failure/Error: sign_in('jack_bruce') ActionController::RoutingError: No route matches [POST] "/session/session_url"

Incorrect: action="session_url"

Correct: action=""

The following crops up when you forget to pass @link to edit_link_url(@link)

Failure/Error: sign_up_as_ginger_baker ActionView::Template::Error: No route matches {:action=>"edit", :controller=>"links"} missing required keys: [:id]

"missing required keys: [:id]" generally means that you forgot to pass an id/object to the route_url

Don't forget that edit_*_url requires a specific object to edit!

Got the following:

Failure/Error: click_button 'Add Comment' ActiveRecord::RecordNotFound: Couldn't find Link with 'id'=

Can't quite remember the original problematic code, but the correct version is:

Add Comment " method="post" >

Redirect to new_session_url, not links_url

Another possible reason your errors may not be rendering (besides not recording them in flash[:errors] or not printing them in the view, is that you may not be validating the presence of those characteristics.

Failure/Error: expect(page).to have_content "Body can't be blank" expected to find text "Body can't be blank" in "Links google http://google.com Edit Link Add Comment ginger_baker"

Solution: validates :body, presence: true

Need to use redirect_to when adding a comment nested in the links show page, even when comment is not valid. Cannot just render link_url(@link)

Failure/Error: click_button 'Add Comment' ActionView::MissingTemplate: Missing template http://www.example.com/links/1 with {:locale=>[:en], :formats=>[:html], :variants=>[], :handlers=>[:erb, :builder, :raw, :ruby]}. Searched in: * "/Users/joy/AA_CodePractice/AppAcademy/Assessment4/a4-practice4/app/views"

Solution: