Building RESTful APIs with Express

Topics:

• Node.js and Express.
• HTTP methods and status codes.
• Reading Request data from body, URL parameters and query string parameters.
• API design and development.

Assignment

Use Node.js and Express to build an API that performs CRUD operations on posts.

Download Project Files and Install Dependencies

• Fork and Clone this repository.
• CD into the folder where you cloned the repository.
• Type yarn or npm install to download all dependencies listed inside package.json.

Database access

Database access will be done using the db.js file included inside the data folder. This file publishes the following methods:

• find: calling find returns a promise that resolves to an array of all the posts contained in the database.
• findById: this method expects an id as it's only parameter and returns the post corresponding to the id provided or an empty array if no post with that id is found.
• insert: calling insert passing it a post object will add it to the database and return an object with the id of the inserted post. The object looks like this: { id: 123 }.
• update: accepts two arguments, the first is the id of the post 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 post from the database it returns the number of records deleted.

Now that we have a way to add, update, remove and retrieve data from the provided databse, it is time to work on the API.

Start the API and Implement Requirements

• To start the server, type yarn start or npm start from the root folder (where the package.json file is). The server is configured to restart automatically as you make changes.
• Add the code necessary to implement the API requirements.
• Test the API using Postman as you work through the exercises.

Post Schema

Posts in the database conform to the following structure:

{
  title: "The post title",
  contents: "The post contents"
}

title is the title of the post, as a String. contents contains the body contents of the post, also as a String.

Provided Code

We have provided a server.js file and a folder called data. Inside the data folder we have added a database with some posts already populated that you can use to test your endpoints as you build them.

Server.js already has db.js required and ready for you to use when building your endpoints.

Write endpoints to perform the following queries.

Configure the API to respond to the following routes:

Method	Endpoint	Description
POST	/api/posts	Creates a post using the information sent inside the request body.
GET	/api/posts	Returns an array of all the post objects contained in the database.
GET	/api/posts/:id	Returns the post object with the specified id.
DELETE	/api/posts/:id	Removes the post with the specified id and returns the deleted post.
PUT	/api/posts/:id	Updates the post with the specified id using data from the request body. Returns the modified document, NOT the original.

Endpoint Specifications

When the client makes a POST request to /api/posts:

• If the request body is missing the title or contents property:

  • cancel the request.
  • respond with HTTP status code 400 (Bad Request).
  • return the following JSON response: { errorMessage: "Please provide title and contents for the post." }.

• If the information about the post is valid:

  • save the new post the the database.
  • return HTTP status code 201 (Created).
  • return the newly created post.

• If there's an error while saving the post:

  • cancel the request.
  • respond with HTTP status code 500 (Server Error).
  • return the following JSON object: { error: "There was an error while saving the post to the database" }.

When the client makes a GET request to /api/posts:

• If there's an error in retrieving the posts from the database:
  • cancel the request.
  • respond with HTTP status code 500.
  • return the following JSON object: { error: "The posts information could not be retrieved." }.

When the client makes a GET request to /api/posts/:id:

• If the post with the specified id is not found:

  • return HTTP status code 404 (Not Found).
  • return the following JSON object: { message: "The post with the specified ID does not exist." }.

• If there's an error in retrieving the post from the database:

  • cancel the request.
  • respond with HTTP status code 500.
  • return the following JSON object: { error: "The post information could not be retrieved." }.

When the client makes a DELETE request to /api/posts/:id:

• If the post with the specified id is not found:

  • return HTTP status code 404 (Not Found).
  • return the following JSON object: { message: "The post with the specified ID does not exist." }.

• If there's an error in removing the post from the database:

  • cancel the request.
  • respond with HTTP status code 500.
  • return the following JSON object: { error: "The post could not be removed" }.

When the client makes a PUT request to /api/posts/:id:

• If the post with the specified id is not found:

  • return HTTP status code 404 (Not Found).
  • return the following JSON object: { message: "The post with the specified ID does not exist." }.

• If the request body is missing the title or contents property:

  • cancel the request.
  • respond with HTTP status code 400 (Bad Request).
  • return the following JSON response: { errorMessage: "Please provide title and contents for the post." }.

• If there's an error when updating the post:

  • cancel the request.
  • respond with HTTP status code 500.
  • return the following JSON object: { error: "The post information could not be modified." }.

• If the post is found and the new information is valid:

  • update the post document in the database using the new information sent in the reques body.
  • return HTTP status code 200 (OK).
  • return the newly updated post.

Stretch Problems

• Use create-react-app to create an application inside the root folder, name it client.
• From the React application connect to the /api/posts endpoint in the API and show the list of posts.
• Style the list of posts however you see fit.