Welcome to Part 7 of the COVIDiary project! If you’re just joining us or missed a post, here’s what we’ve done so far:
- Part 1: Project Introduction
- Part 2: Initial Setup
- Part 3: Building the Database
- Part 4: Frontend Setup
- Part 4.5: Database Fixes
- Part 5: Backend Routing
- Part 6: Formatting Data
This week, we’re going to continue work on the back end, in CD-API. By the end of today, we will have basic CRUD actions for our Users and their Entries.
Today’s post will be a little long. Get yourself a Pepsi and some snacks, and settle in, friends.
#public Class Method
If you’ll recall, we added the is_public boolean to our entries table. We want users to be able to decide if others can see their posts or not. When we fetch from api/entries, we should only see the entries that have been marked as public. Let’s add a class method to our Entry class in models/entry.rb:
# returns all the entries where is_public equals true
def self.public
self.all.select {|entry| entry.is_public? == true}
end
Controller Modifications
Right now, our controllers are basically empty. Let’s build them out a bit. For the moment, we want CRUD (Create, Read, Update/edit, Destroy/delete) actions for both Users and Entries. We will probably tweak these some once we start manipulating data from the front end, but we’ll have a solid start by the end of today.
Let’s start by building out our UsersController in controllers/api/users_controller.rb. As you look through the following code snippets, remember to read the comments, which are preceded by the # symbol.
class Api::UsersController < ApplicationController
# GET api/users
# This action lists ALL the users in our database
def index
users = User.all
render json: UserSerializer.new(users)
end
# POST api/users
# This action creates a new user, given the provided parameters
def create
user = User.create(user_params)
if user.save
render json: UserSerializer.new(user)
else
render json: { error: "Error creating user" }
end
end
# GET api/users/:id
# This action shows a specific user, determined by the :id parameter
def show
user = User.find(params[:id])
render json: UserSerializer.new(user)
end
# PATCH api/users/:id/
# This action allows a user to update his or her data.
def update
user = User.find(params[:id])
if user.update(user_params)
render json: UserSerializer.new(user)
else
render json: { error: "Error updating user" }
end
end
# DELETE api/users/:id
# This action completely removes a user from the database
# We may want to update this later to also destroy a user's entries
def destroy
user = User.find(params[:id])
user.destroy
end
private
# Determine which parameters to allow from a form submission
def user_params
params.require(:user).permit(
:id,
:first_name,
:last_name,
:email,
:birth_date,
:occupation,
:is_essential,
:isolation_start,
:isolation_end,
:about
)
end
end
Are you still with me?
Let’s add the CRUD actions for our EntriesController in controllers/api/entries_controller.rb.
class Api::EntriesController < ApplicationController
# before we call a controller action, call the #set_user private method
before_action :set_user
# GET api/users/:user_id/entries OR api/entries
# This action lists ALL the entries in the database OR all the entries for a given user.
def index
# if there is a user in the params, only show their entries.
# Otherwise, only show the public entries.
# TODO: edit user entries so they only show private ones if it is the current user
entries = @user ? @user.entries : Entry.public
options = {
include: [:user]
}
render json: EntrySerializer.new(entries, options)
end
# POST api/users/:user_id/entries
# This action creates a new entry assigned to a given user
def create
entry = @user.entries.build(entry_params)
if entry.save
render json: EntrySerializer.new(entry)
else
render json: { error: "Error creating entry" }
end
end
# GET api/users/:user_id/entries/:id
# This action shows a specific entry for a given user
def show
entry = Entry.find(params[:id])
options = {
include: [:user]
}
render json: EntrySerializer.new(entry, options)
end
# PATCH api/users/:user_id/entries/:id
# This action allows a user to update his or her entry.
def update
entry = Entry.find(params[:id])
if entry.update(entry_params)
render json: EntrySerializer.new(entry)
else
render json: { error: "Error updating entry" }
end
end
# DELETE api/users/:user_id/entries/:id
# This action completely removes an entry from the database
def destroy
entry = Entry.find(params[:id])
entry.destroy
end
private
# This method allows us to find a specific user
def set_user
if params[:user_id]
@user = User.find(params[:user_id])
end
end
# Determine which parameters to allow from a form submission
def entry_params
params.require(:entry).permit(
:id,
:user_id,
:health_rating,
:is_symptomatic,
:health_comments,
:mental_health_rating,
:mental_health_comments,
:diary_entry,
:is_public,
:created_at
)
end
end
Coming Up
Our back end is ready to deliver information to the Client app. Next week, we’ll test that connection with a few fetch() requests to make sure everything is running smoothly.
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