Building a Web API Once you have Your sample dataset loaded into your cluster (Step 1), we

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Building a Web API

Once you have Your sample dataset loaded into your cluster (Step 1), we must build and publish a Web API to enable code on the client-side to work with the data.

To get started:

First folder (ie: "moviesAPI") for your project somewhere on your machine. Next, open this folder in Visual Studio code and proceed to simple server using the Express framework. At this point only a single GET route "/" is required which returns the following object (JSON): {message: "API Listening"}.

NOTE: This is to ensure that your environment is set up correctly and that you're able to run / test the server locally.

Next, install the "cors" package using npm. This must be imported ("required") and used in its simplest form as a middleware function, declared before your routes, ie: app.use(cors());

Another package that we will need from npm is "dotenv" to enable our code to read from a ".env" file. This is also used in its simplest form, placed alongside your other require statements: require('dotenv').config();

To ensure that our server can parse the JSON provided in the request body for some of our routes (declared below) we can use the express.json() built-in middleware (ie: app.use(express.json())).

Next, install the "mongoose" ODM using npm. This will be used by your "moviesDB.js" module (to be downloaded shortly)

Finally, creat .gitignore file at the root of your "moviesAPI" folder. The contents of this file should be:

node_modules
.env

Once you have installed your dependencies and configured .gitingore, initialize an empty Git repository for this folder using the command "git init"

Adding moviesDB.js Module:

Now that your server is up and running, we must add the module that will provide the functionality to connect to the "movies" collection within the newly created "sample_mflix" Database:

First, creat "modules" folder within your solution to house the "moviesDB.js" module.

Next, create the file "moviesDB.js" within the "modules" folder and proceed to copy the code from here. (this is the completed "moviesDB.js" module, for use with this assignment)

Finally, back in your server.js file add the following lines to "require" the newly created "moviesDB.js" module, as well as to creat new "db" instance to work with the data:

const MoviesDB = require("./modules/moviesDB.js");

const db = new MoviesDB();

Obtaining the "MongoDB Connection String"

On the MongoDB Atlas dashboard, ensure that you're looking at the overview for your newly created Cluster (within your newly created Project) that contains the sample data.

Next, click the "CONNECT" button and grab the connection string using the "Connect Your Application" button. NOTE: If you have not yet created a user for this database, or whitelisted the ip: 0.0.0.0/0, please proceed to do this first.
Once you have your connection string, it should look something like t..;@cluster0-abc0d.mongodb.net/?retryWrites=true&w=majority
Next, replace the entire string with your password for this cluster (ie: do not include the < & > characters)
Finally, add database name: sample_mflix after "mongodb.net/", ie:
... mongodb.net/sample_mflix?retryWrites ... and place the updated connection string in your .env file using the following syntax:

MONGODB_CONN_STRING=myUdatedConnectionString

Where myUpdatedConnectionString is your completed connection string (above)

"Initializing" the Module before the server starts

To ensure that we can indeed connect to the MongoDB Atlas cluster with our new connection string (stored in .env), we must invoke the db.initialize(process.env.MONGODB_CONN_STRING) method and only start the server once it has succeeded, otherwise we should show the error message in the console, ie:

db.initialize(process.env.MONGODB_CONN_STRING).then(()=>{

app.listen(HTTP_PORT, ()=>{

console.log(`server listening on: ${HTTP_PORT}`);

});

}).catch((err)=>{

console.log(err);

});

Reviewing the moviesDB.js Module (db)

This module will provide the 6 (promise-based) functions required by our Web API for this particular dataset, ie:

db.initialize(connectionString): Establish a connection with the MongoDB server and initialize the "Movie" model with the "movies" collection (used above)
db.addNewMovie(data): Creat new movie in the collection using the object passed in the "data" parameter
db.getAllMovies(page, perPage, title): Return an array of all movies for a specific page (sorted by year), given the number of items per page. For example, if page is 2 and perPage is 5, then this function would return a sorted list of movies (by year), containing items 6 - 10. This will help us to deal with the large amount of data in this dataset and make paging easier to implement in the UI later.

Additionally, there is an optional parameter "title" that can be used to filter results by a specific (case sensitive) "title" value
db.getMovieById(Id): Return a single movie object whose "_id" value matches the "Id" parameter
updateMovieById(data,Id): Overwrite an existing movie whose "_id" value matches the "Id" parameter, using the object passed in the "data" parameter.
deleteMovieById(Id): Delete an existing movie whose "_id" value matches the "Id" parameter

Add the routes

The next piece that needs to be completed before we have a functioning Web API is to actually define the routes (listed Below). Note: Do not forget to return an error message if there was a problem and make use of the status codes 201, 204 and 500 where applicable.

POST /api/movies

This route uses the body of the request to add a new "Movie" document to the collection and return the newly created movie object / fail message to the client.

GET /api/movies

This route must accept the numeric query parameters "page" and "perPage" as well as the (optional) string parameter "title", ie: /api/movies?page=1&perPage=5&title=The Avengers. It will use these values to return all "Movie" objects for a specific "page" to the client as well as optionally filtering by "title", if provided (in this case, it will show both "The Avengers" films).

GET /api/movies

This route must accept a route parameter that represents the _id of the desired movie object, ie: /api/movies/573a1391f29313caabcd956e. It will use this parameter to return a specific "Movie" object to the client.

PUT /api/movies

This route must accept a route parameter that represents the _id of the desired movie object, ie: /api/movies/573a1391f29313caabcd956e as well as read the contents of the request body. It will use these values to update a specific "Movie" document in the collection and return a success / fail message to the client.

DELETE /api/movies

This route must accept a route parameter that represents the _id of the desired movie object, ie: /api/movies/573a1391f29313caabcd956e. It will use this value to delete a specific "Movie" document from the collection and return a success / fail message to the client.