Building an API using a Node.js and Express Middleware

In this challenge, you build an API and write custom middleware that satisfies the requirements listed under the Minimum Viable Product section.

Instructions

Read these instructions carefully. Understand exactly what is expected before starting.

You are allowed, and encouraged, to collaborate with other peers. Please follow the twenty-minute rule, before seeking support from your TL and Instructor.

Project Set Up

• Create a forked copy of this project.
• Add your Team Lead as collaborator on Github.
• Clone your OWN version of the repository.
• Create a new branch: git checkout -b <firstName-lastName>.
• Implement the project on your newly created <firstName-lastName> branch, committing changes regularly.
• Push commits: git push origin <firstName-lastName>.

Follow these steps for completing your project.

• Submit a Pull-Request to merge Branch into master (student's Repository). Please don't merge your own pull request
• Add your Team Lead as a reviewer on the pull-request
• Your Team Lead will count the project as complete by merging the branch back into master.
• Do your magic!

Minimum Viable Product

1. Write and implement four custom middleware functions, detailed below.
2. Build an API to let clients perform CRUD operations on users.
3. Add endpoints to retrieve the list of posts for a user and to store a new post for a user.

Custom Middleware Requirements

• logger()

  • logger logs to the console the following information about each request: request method, request url, and a timestamp
  • this middleware runs on every request made to the API

• validateUserId()

  • validateUserId validates the user id on every request that expects a user id parameter
  • if the id parameter is valid, store that user object as req.user
  • if the id parameter does not match any user id in the database, cancel the request and respond with status 400 and { message: "invalid user id" }

• validateUser()

  • validateUser validates the body on a request to create a new user
  • if the request body is missing, cancel the request and respond with status 400 and { message: "missing user data" }
  • if the request body is missing the required name field, cancel the request and respond with status 400 and { message: "missing required name field" }

• validatePost()

  • validatePost validates the body on a request to create a new post
  • if the request body is missing, cancel the request and respond with status 400 and { message: "missing post data" }
  • if the request body is missing the required text field, cancel the request and respond with status 400 and { message: "missing required text field" }

Database Persistence Helpers

There are two helper files that you can use to manage the persistence of users and posts data. These files are users/userDb.js and posts/postDb.js. Both files publish the following api:

• get(): calling find returns a promise that resolves to an array of all the resources contained in the database.
• getById(): takes an id as the argument and returns a promise that resolves to the resource with that id if found.
• insert(): calling insert passing it a resource object will add it to the database and return the new resource.
• update(): accepts two arguments, the first is the id of the resource to update and the second is an object with the changes to apply. It returns the count of updated records. If the count is 1 it means the record was updated correctly.
• remove(): the remove method accepts an id as it's first parameter and, upon successfully deleting the resource from the database, returns the number of records deleted.

The userDb.js helper includes an extra method called getUserPosts() that when passed a user's id, returns a list of all the posts for the user.

All helper methods return a promise.

Database Schemas

The Database Schemas for the users and posts resources are:

Users

field	data type	metadata
id	unsigned integer	primary key, auto-increments, generated by database
name	string	required, unique

Posts

field	data type	metadata
id	unsigned integer	primary key, auto-increments, generated by database
text	text	required
user_id	unsigned integer	required, must be the id of an existing user

We have provided test data for the resources.

Stretch Goals

• Add the Post Router

  • Implement all endpoints and middleware within posts/postRouter.js

• Create a React App

  • Use create-react-app to create an application inside the root folder, name it client.
  • From the React application connect to the /api/users endpoint in the API and show the list of users.
  • Add functionality to show the details of a user, including their posts, when clicking a user name in the list. Use React Router to navigate to a /users/:id route to show the user details.
  • Add styling!