Programming Phoenix Chapter 5

Question 1

Where's the error message come from in the UI?

Accepted Answer

put_flash in defp authenticate and get_flash in the view

Question 2

To use our UserController.authenticate function in a bunch of actions easily, we can use…

Accepted Answer

a plug right in the controller, plug :authenticate

Question 3

If you need a refresher on case statements, you can find them in the Elixir School chapter on…

Accepted Answer

Control Structures

Question 4

What functions must a module plug define?

Accepted Answer

init, call

Question 5

Which params for registration_changeset will return a match for %Ecto.Changeset{ valid?: true }

Accepted Answer

%{ username: "!", password: "123456", admin: "true"}

Question 6

In Rumbl.Auth.init, it uses Keyword.fetch!(opts, :repo). What's this do?

Accepted Answer

Like opts.repo but raises an error if repo isn't defined

Question 7

~w(name username) is a faster way of saying ["name", "username"]

Accepted Answer

true

Question 8

Plugs aren't automatically available to all controllers. They get added via a pipeline in…

Accepted Answer

PROJECT_ROOT/web/router.ex

Question 9

The following module plug will add :current_user to conn. How can controllers access it?

Accepted Answer

conn.assigns.current_user

Question 10

In a model, cast comes from Ecto.Changeset in the web/web.ex file. To read more about it…

Accepted Answer

any/all of the above

Question 11

If this is given an invalid changeset, it…

Accepted Answer

returns the changeset unchanged

Question 12

In working through your app, the conn morphs from the user's question into your answer.

Accepted Answer

true

Question 13

You added a new dependency to the deps array in mix.exs file. To install them, you run…

Accepted Answer

mix deps.get

Question 14

Like guitar pedals tweaking audio signals, so plugs in your app gradually change the conn

Accepted Answer

true

Question 15

Where's the bug in this code?

Accepted Answer

There ain't no bug, bruh

Question 16

What even is a conn, tho?

Accepted Answer

A connection. Info about the user and what they want.

Question 17

You forget where cast comes from in your User model. Where's a good spot to start your search?

Accepted Answer

PROJECT_ROOT/web/web.ex

Question 18

You can now build your own auth for your Phoenix applications!

Accepted Answer

true, false

Question 19

Ok, so now we know how to write a modern changeset. Great. What does cast do?

Accepted Answer

Turns unsafe form params into a safe Ecto.Changeset

Question 20

If you want to share a plug across more than one module, you should use a…

Accepted Answer

module plug

Question 21

Which of the following is a function plug?

Accepted Answer

plug :protect_from_forgery

Question 22

The book is outdated in another way, too! What's the new way of writing cast?

Accepted Answer

cast(params, [:name, :username])

Question 23

The changeset function is defined in the model, but where is it used?

Accepted Answer

Controllers

Question 24

If this is given a valid changeset, it…

Accepted Answer

adds a :password_hash key to the changeset

Question 25

Which of the following is a module plug?

Accepted Answer

plug Plug.Logger

Question 26

All plugs take a conn and return a conn

Accepted Answer

true

Question 27

The book is wrong here with that :empty business! Instead, you need…

Accepted Answer

either of the above

Question 28

Which is called at compile time, and which is called at runtime?

Accepted Answer

init: compile time, call: runtime

Question 29

Now in a controller you can call halt if conn.assigns.current_user isn't there. What's that do?

Accepted Answer

prevents downstream transformations to conn

Programming Phoenix Chapter 5

Questions 29

Programming Phoenix Chapter 5

Questions 29