Creating React/Flask apps that connect to PostgreSQL and HarperDB
Tags: javascript, webdev, tutorial, react
Published: 2020-10-06 08:10:57

I'm sure that most of you are already more than familiar with the MERN stack. Having a React front end with a Node/Express back end that connects to a MongoDB database. Well, I will show you just how easy it is to connect to a Flask back end which uses a PostgreSQL database to persist the data. And as a bonus I will even show you how to connect to [https://harperdb.io/](https://harperdb.io/) which is a SQL/NoSQL data management platform. It is fully indexed, doesn't duplicate data, and runs on any device from the edge to the cloud.

I will assume that you already have an understanding of Python, Flask and SQL as this guide is meant to be a quick introduction.

You will be creating an app that looks like the image below.

![https://res.cloudinary.com/d74fh3kw/image/upload/v1601743727/meta-movies-blog_rh9omg.png](https://res.cloudinary.com/d74fh3kw/image/upload/v1601743727/meta-movies-blog_rh9omg.png 'Meta Movies')

**Prerequisites**

- Insomnia or Postman API App installed
- NPM/Node Installed on your computer
- Python3 installed and setup
- PostgreSQL installed and setup
- pip3 installed with the below packages installed as well

[https://pypi.org/project/Flask/](https://pypi.org/project/Flask/)

[https://pypi.org/project/Flask-Cors/](https://pypi.org/project/Flask-Cors/)

[https://pypi.org/project/python-dotenv/](https://pypi.org/project/python-dotenv/)

[https://pypi.org/project/psycopg2/](https://pypi.org/project/psycopg2/) (including the binaries at the bottom) `pip install psycopg2-binary`

[https://pypi.org/project/harperdb/](https://pypi.org/project/harperdb/)

## Create a PostgreSQL Database

For this guide I will be using Valentina Studio as a GUI to manage the local PostgreSQL database which you can find here [https://www.valentina-db.com/en/valentina-studio-overview](https://www.valentina-db.com/en/valentina-studio-overview) However feel free to use whatever tool you like you can even use the command line to interact with your database if you prefer.

Firstly create a database called `metacritic` and then use the SQL below the images to create a table called movies.

![https://res.cloudinary.com/d74fh3kw/image/upload/v1601740643/create-database_ss4dhj.jpg](https://res.cloudinary.com/d74fh3kw/image/upload/v1601740643/create-database_ss4dhj.jpg 'Create SQL Database')

![https://res.cloudinary.com/d74fh3kw/image/upload/v1601740641/sql-query-editor_zekzhp.jpg](https://res.cloudinary.com/d74fh3kw/image/upload/v1601740641/sql-query-editor_zekzhp.jpg 'Open SQL Editor')

![https://res.cloudinary.com/d74fh3kw/image/upload/v1601740643/create-table_zohikv.jpg](https://res.cloudinary.com/d74fh3kw/image/upload/v1601740643/create-table_zohikv.jpg 'Create SQL Table')

```sql
CREATE TABLE movies (
    movie_id SERIAL PRIMARY KEY,
    movie_name VARCHAR(200) NOT NULL,
    img_url TEXT NOT NULL,
    release_year INT NOT NULL,
    summary TEXT NOT NULL,
    director VARCHAR(200) NOT NULL,
    genre VARCHAR(100) NOT NULL,
    rating VARCHAR(100) NOT NULL,
    movie_runtime INT NOT NULL,
    meta_score INT NOT NULL
)
```

Then use the SQL below the image to add some data to the table movies.

![https://res.cloudinary.com/d74fh3kw/image/upload/v1601740647/insert-data_d0f7mz.jpg](https://res.cloudinary.com/d74fh3kw/image/upload/v1601740647/insert-data_d0f7mz.jpg 'Insert data into table movies')

```sql
INSERT INTO movies (movie_name, img_url, release_year, summary, director, genre, rating, movie_runtime, meta_score)
VALUES ('Casino Royale', 'https://static.metacritic.com/images/products/movies/9/08b5f3a45845fa3b6d1cb5f4978b5081-250h.jpg', 2006, 'After earning his license to kill James Bonds first 007 mission takes him to Madagascar where he is to spy on a terrorist. Not everything goes as planned and Bond decides to investigate independently of MI6.', 'Martin Campbell', 'Action', 'PG-13', 144, 80),('Tenet', 'https://static.metacritic.com/images/products/movies/7/a60818c40f69031bf30ca846444011e4-250h.jpg', 2020, 'Armed with only one word - Tenet - and fighting for the survival of the entire world the Protagonist (John David Washington) journeys through a twilight world of international espionage on a mission that will unfold in something beyond real time. Not time travel. Inversion.', 'Christopher Nolan', 'Action', 'PG-13', 150, 69),('Mulan', 'https://static.metacritic.com/images/products/movies/0/a496c3f832582876dc9b0d66197cab78-250h.jpg', 2020, 'When the Emperor of China issues a decree that one man per family must serve in the Imperial Army to defend the country from Northern invaders Hua Mulan the eldest daughter of an honored warrior steps in to take the place of her ailing father. Masquerading as a man Hua Jun she is tested every step of the way and must harness her inner-strength and embrace her true potential. It is an epic journey that will transform her into an honored warrior and earn her the respect of a grateful nation…and a proud father.', 'Niki Caro', 'Action', 'PG-13', 115, 67),('The Old Guard','https://static.metacritic.com/images/products/movies/7/b1db3c24db156b33c9fcfbbc199fcfcb-250h.jpg', 2020, 'Led by a warrior named Andy (Charlize Theron) a covert group of tight-knit mercenaries with a mysterious inability to die have fought to protect the mortal world for centuries. But when the team is recruited to take on an emergency mission and their extraordinary abilities are suddenly exposed it’s up to Andy and Nile (Kiki Layne) the newest soldier to join their ranks to help the group eliminate the threat of those who seek to replicate and monetize their power by any means necessary.', 'Gina Prince-Bythewood', 'Action', 'R', 125, 70),('Greyhound', 'https://static.metacritic.com/images/products/movies/4/499215874bac5acda666be3659bacf7e-250h.jpg', 2020, 'In the early days of WWII an international convoy of 37 Allied ships led by captain Ernest Krause (Tom Hanks) in his first command of a U.S. destroyer crosses the treacherous North Atlantic while hotly pursued by wolf packs of Nazi U-boats.', 'Aaron Schneider', 'Action', 'PG-13', 91, 64),('The New Mutants', 'https://static.metacritic.com/images/products/movies/4/8fcef9e9a93457f7a0fdf2a51cf30a0d-250h.jpg', 2020, 'In an isolated hospital young mutants are being held for psychiatric monitoring. When strange occurrences begin to take place both their new mutant abilities and their friendships will be tested as they battle to try and make it out alive.', 'Josh Boone', 'Action', 'PG-13', 94, 43),('I Used to Go Here', 'https://static.metacritic.com/images/products/movies/5/9456ab11b0bd3b457f32c6c58157bf95-250h.jpg', 2020, 'Following the lackluster launch of her debut novel 35-year-old writer Kate Conklin (Gillian Jacobs) receives an invitation from her former professor and old crush (Jemaine Clement) to speak at her alma mater. With her book tour canceled and her ego deflated Kate decides to take the trip wondering if returning to her old college as a published author might give her the morale boost she sorely needs. Instead she falls into a comical regression – from misadventures with eccentric twenty-year-olds to feelings of jealousy toward her former professor’s new favorite student. Striking the balance between bittersweet and hilarious Kate takes a journey through her past to redefine her future.', 'Kris Rey', 'Comedy', 'PG-13', 80, 68),('Hooking Up', 'https://static.metacritic.com/images/products/movies/0/fffb93ea39fcce7d65563163daa57c4c-250h.jpg', 2020, 'She (Brittany Snow) is an adventurous writer pumping out scandalous content for a lifestyle magazine. He (Sam Richardson) is a hopeless romantic who’s just been dumped by his high school sweetheart and given a medical diagnosis that’s left him shook. After a chance meeting the mismatched duo hit the road on a cross country trip to provide them both some much needed healing.', 'Nico Raineau', 'Drama', 'R', 104, 44),('Infamous', 'https://static.metacritic.com/images/products/movies/4/6da52f15b0fec577a53de1255cff6518-250h.jpg', 2020, 'Living in a small Florida town and working at a diner was never Arielles (Bella Thorne) dream life. Shes always wanted more. Fame. Popularity. Admiration. When she falls for a recently paroled young criminal named Dean she drags him back into a life of danger learning that posting their criminal exploits on social media is an easy way to viral fame. Obsessed with their rising number of followers they embark on a dangerous adventure together that leads to robbery cop chases and even murder. Heading to Hollywood the City of Stars they will realize what it takes to become famous and have to decide if this dangerous lifestyle is really worth it.', 'Joshua Caldwell', 'Drama', 'PG-13', 100, 40),('The LEGO Movie', 'https://static.metacritic.com/images/products/movies/7/55a09ad4264baf7d3e32b23a693d2307-250h.jpg', 2014, 'An ordinary LEGO minifigure, mistakenly thought to be the extraordinary MasterBuilder, is recruited to join a quest to stop an evil LEGO tyrant from gluing the universe together.', 'Christopher Miller and Phil Lord', 'Action', 'PG', 100, 83)
```

Run the SQL below to see all of the data in the table movies.

```sql
SELECT * FROM movies
```

![https://res.cloudinary.com/d74fh3kw/image/upload/c_scale,w_800/v1601740641/select-all-movies_vqxgrh.jpg](https://res.cloudinary.com/d74fh3kw/image/upload/c_scale,w_800/v1601740641/select-all-movies_vqxgrh.jpg)

## Create a Flask back end Server

First navigate to a location like your desktop or a folder and then use the code below to set up your project by using your terminal application.

If you are having problems getting the virtual environment to work then read this documentation [https://docs.python.org/3/library/venv.html](https://docs.python.org/3/library/venv.html)

```bash
mkdir meta-movies-app
cd meta-movies-app
python3 -m venv backend
. backend/bin/activate
cd backend
touch index.py
```

Open the project in your code editor and then create a Python/Flask server in the `index.py` file

```python
from flask import Flask


app = Flask(__name__)


@app.route('/')
def home():
    return 'Home Page Route'
```

Setup the development environment by running these commands in your terminal.

```bash
export FLASK_APP=index.py
export FLASK_ENV=development
```

Run the application and go to your browser window to see the homepage.

```bash
flask run
```

## Connect to the PostgreSQL database

Firstly create a `.gitignore` file and put it in the root folder for backend with the code below inside of it

```bash
.env
```

Next create a `.env` file and put it in your root folder. Add your database name, username and password like in the example below. I believe that the username is always **postgres** when working with postgres databases locally.

```bash
DATABASE="metacritic"
DATABASE_USERNAME="postgres"
DATABASE_PASSWORD="yourdatabasepassword"
```

Now update the `index.py` file in the root folder with the code below.

```python
from flask import Flask, jsonify
from flask_cors import CORS
from dotenv import load_dotenv
import psycopg2
import os

load_dotenv()

# PostgreSQL Database credentials loaded from the .env file
DATABASE = os.getenv('DATABASE')
DATABASE_USERNAME = os.getenv('DATABASE_USERNAME')
DATABASE_PASSWORD = os.getenv('DATABASE_PASSWORD')

app = Flask(__name__)

# CORS implemented so that we don't get errors when trying to access the server from a different server location
CORS(app)


try:
    con = psycopg2.connect(
        database=DATABASE,
        user=DATABASE_USERNAME,
        password=DATABASE_PASSWORD)

    cur = con.cursor()

    # GET: Fetch all movies from the database
    @app.route('/')
    def fetch_all_movies():
        cur.execute('SELECT * FROM movies')
        rows = cur.fetchall()
        print(rows)

        return jsonify(rows)
except:
    print('Error')

```

Your server should still be running so all you need to do is go to your browser window and reload the page. You should see the data in your database for the table movies returned as json and the data is also printed to your terminal window. One thing to note is that the data is returned as a Python Tuple which looks like a JavaScript Array. So essentially it looks like an array of arrays and not an array of objects which is more common. This will be important when we get to the front end section and you have to output the data to the DOM.

You can look at the documentation for the psycopg2 package to learn more about the code [https://www.psycopg.org/docs/](https://www.psycopg.org/docs/)

## Implementing some CRUD functionality

Replace the code in your `index.py` file with the code below. It is now possible to create, read update and delete data from the database.

```python
from flask import Flask, jsonify, request
from flask_cors import CORS
from dotenv import load_dotenv
import psycopg2
import os

load_dotenv()

# PostgreSQL Database credentials loaded from the .env file
DATABASE = os.getenv('DATABASE')
DATABASE_USERNAME = os.getenv('DATABASE_USERNAME')
DATABASE_PASSWORD = os.getenv('DATABASE_PASSWORD')

app = Flask(__name__)

# CORS implemented so that we don't get errors when trying to access the server from a different server location
CORS(app)


try:
    con = psycopg2.connect(
        database=DATABASE,
        user=DATABASE_USERNAME,
        password=DATABASE_PASSWORD)

    cur = con.cursor()

    # GET: Fetch all movies from the database
    @app.route('/')
    def fetch_all_movies():
        cur.execute('SELECT * FROM movies')
        rows = cur.fetchall()
        print(rows)

        return jsonify(rows)

    # GET: Fetch movie by movieId from the database
    @app.route('/<int:movie_id>')
    def fetch_by_id(movie_id=None):
        cur.execute(f'SELECT * FROM movies WHERE movie_id = {movie_id}')
        rows = cur.fetchall()
        print(rows)

        return jsonify(rows)

    # POST: Create movies and add them to the database
    @app.route('/add-movie', methods=['GET', 'POST'])
    def add_movie():
        if request.method == 'POST':
            data = request.form.to_dict()
            print(data)
            cur.execute("INSERT INTO movies (movie_name, img_url, release_year, summary, director, genre, rating, movie_runtime, meta_score) VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s)",
                        (f"{data['movieName']}", f"{data['imgUrl']}", data['releaseYear'], f"{data['summary']}",
                         f"{data['director']}", f"{data['genre']}", f"{data['rating']}", data['movieRuntime'], data['metaScore']))
            con.commit()
            return 'Form submitted'
        else:
            return 'Form submission failed'

    # DELETE: Delete movie by movieId from the database
    @app.route('/delete-movie', methods=['GET', 'DELETE'])
    def delete_by_id():
        movie_id = request.form.to_dict()
        print(movie_id['movieId'])
        cur.execute(
            f"DELETE FROM movies WHERE movie_id = {movie_id['movieId']} RETURNING movie_name")
        con.commit()

        return 'Movie Deleted'

    # PUT: Update movie by movieId from the database
    @app.route('/update-movie', methods=['GET', 'PUT'])
    def update_by_id():

        cur.execute(
            'UPDATE movies SET movie_name = \'Goldeneye\' WHERE movie_id = 1')
        con.commit()

        return 'Movie Updated'

except:
    print('Error')

```

### Using an API tool to test the different endpoints

In this guide I will be using the Insomnia API app to perform different CRUD requests. Use the screenshots as an example to see it work on your computer.

**GET: Fetch all movies from the database**

Just go to [http://127.0.0.1:5000/](http://127.0.0.1:5000/) and hit send to see all of the database data returned as json

![https://res.cloudinary.com/d74fh3kw/image/upload/v1601560293/fetch_all_egp8v5.jpg](https://res.cloudinary.com/d74fh3kw/image/upload/v1601560293/fetch_all_egp8v5.jpg 'Fetch all movies')

**GET: Fetch movie by movieId from the database**

Just go to [http://127.0.0.1:5000/1](http://127.0.0.1:5000/1) and hit send to see the movie that is matched with that ID returned as json. It will work with any ID number as long as it is in the database.

![https://res.cloudinary.com/d74fh3kw/image/upload/v1601560293/fetch_by_movieId_afkn0e.jpg](https://res.cloudinary.com/d74fh3kw/image/upload/v1601560293/fetch_by_movieId_afkn0e.jpg 'Fetch movie by movieId')

**POST: Create movies and add them to the database**

Send a POST request to [http://127.0.0.1:5000/add-movie](http://127.0.0.1:5000/add-movie) with key value pair data as displayed in the example screenshot. Then go to the Fetch all movies route to see the new entry. Alternatively you can just use your database GUI or the CLI to see the new database entry.

![https://res.cloudinary.com/d74fh3kw/image/upload/v1601560293/post_qzeccc.jpg](https://res.cloudinary.com/d74fh3kw/image/upload/v1601560293/post_qzeccc.jpg 'Add to the database')

**DELETE: Delete movie by movieId from the database**

Send a DELETE request to the route [http://127.0.0.1:5000/delete-movie](http://127.0.0.1:5000/delete-movie) using the name movieId. And as the value use any ID that is in the database to delete that entry.

![https://res.cloudinary.com/d74fh3kw/image/upload/v1601560293/delete_k3zcif.jpg](https://res.cloudinary.com/d74fh3kw/image/upload/v1601560293/delete_k3zcif.jpg 'Delete from the database')

**PUT: Update movie by movieId from the database**

Simply go to [http://127.0.0.1:5000/update-movie](http://127.0.0.1:5000/update-movie) using your API app or in the browser to make an update to a database entry. Go to the bottom of the `index.py` file to see the code for the UPDATE route. You can change the SQL query to update any of the fields in the table and then all you have to do is select the movie_id to update its entry. You can see the Python code and SQL query below.

Python

```python
# PUT: Update movie by movieId from the database
    @app.route('/update-movie', methods=['GET', 'PUT'])
    def update_by_id():

        cur.execute(
            'UPDATE movies SET movie_name = \'Goldeneye\' WHERE movie_id = 1')
        con.commit()

        return 'Movie Updated'
```

SQL

```sql
UPDATE movies SET movie_name = 'Goldeneye'
WHERE movie_id = 1
```

Well done you just created a Flask app that connects to a PostgreSQL database. The next section will be about HarperDB.

## Create a HarperDB Database

First you need to create a HarperDB account and then create a database. I called my database "movies". Creating and setting up a HarperDB Database is very easy. Just follow this video [HarperDB Cloud Launch Tour](https://www.youtube.com/watch?v=fAKZxK-XamM&t=0s) and you can also take a look at the documentation for the HarperDB Python package here [https://pypi.org/project/harperdb/](https://pypi.org/project/harperdb/).

**Login Credentials**

You might need an authorisation code to connect to HarperDB and if that is the case this is how you find it. First use your API tool to send a GET request to your HarperDB URL with your username and password. You need to use Basic Auth. Then use the generate code button and select Node.js and HTTP you will find your authorisation code in the headers code. The images below show you how it's done.

![https://res.cloudinary.com/d74fh3kw/image/upload/v1601839963/harper-db-login_y1a2ym.jpg](https://res.cloudinary.com/d74fh3kw/image/upload/v1601839963/harper-db-login_y1a2ym.jpg 'HarperDB Insomnia Login')

![https://res.cloudinary.com/d74fh3kw/image/upload/v1601839963/auth-code_ht1oel.jpg](https://res.cloudinary.com/d74fh3kw/image/upload/v1601839963/auth-code_ht1oel.jpg 'HarperDB Auth')

**Connecting to HarperDB**

Once you are set up make sure that you update your `.env` file with your HarperDB credentials like below.

```bash
DATABASE="metacritic"
DATABASE_USERNAME="postgres"
DATABASE_PASSWORD="yourdatabasepassword"
HARPERDB_URL="https://yourdatabase.harperdbcloud.com/"
HARPERDB_USERNAME="admin"
HARPERDB_PASSWORD="yourpassword"
```

Now update your `index.py` file with the code below. We imported HarperDB, the database credentials for it and also created routes which you can find at the bottom with full CRUD requests.

```python
from flask import Flask, jsonify, request
from flask_cors import CORS
from dotenv import load_dotenv
import psycopg2
import os
import harperdb

load_dotenv()

# PostgreSQL Database credentials loaded from the .env file
DATABASE = os.getenv('DATABASE')
DATABASE_USERNAME = os.getenv('DATABASE_USERNAME')
DATABASE_PASSWORD = os.getenv('DATABASE_PASSWORD')

# HarperDB Database credentials loaded from the .env file
HARPERDB_URL = os.getenv('HARPERDB_URL')
HARPERDB_USERNAME = os.getenv('HARPERDB_USERNAME')
HARPERDB_PASSWORD = os.getenv('HARPERDB_PASSWORD')

db = harperdb.HarperDB(
    url=HARPERDB_URL,
    username=HARPERDB_USERNAME,
    password=HARPERDB_PASSWORD)

app = Flask(__name__)

# CORS implemented so that we don't get errors when trying to access the server from a different server location
CORS(app)


try:
    con = psycopg2.connect(
        database=DATABASE,
        user=DATABASE_USERNAME,
        password=DATABASE_PASSWORD)

    cur = con.cursor()

    # GET: Fetch all movies from the database
    @app.route('/')
    def fetch_all_movies():
        cur.execute('SELECT * FROM movies')
        rows = cur.fetchall()
        print(rows)

        return jsonify(rows)

    # GET: Fetch movie by movieId from the database
    @app.route('/<int:movie_id>')
    def fetch_by_id(movie_id=None):
        cur.execute(f'SELECT * FROM movies WHERE movie_id = {movie_id}')
        rows = cur.fetchall()
        print(rows)

        return jsonify(rows)

    # POST: Create movies and add them to the database
    @app.route('/add-movie', methods=['GET', 'POST'])
    def add_movie():
        if request.method == 'POST':
            data = request.form.to_dict()
            print(data)
            cur.execute("INSERT INTO movies (movie_name, img_url, release_year, summary, director, genre, rating, movie_runtime, meta_score) VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s)",
                        (f"{data['movieName']}", f"{data['imgUrl']}", data['releaseYear'], f"{data['summary']}",
                         f"{data['director']}", f"{data['genre']}", f"{data['rating']}", data['movieRuntime'], data['metaScore']))
            con.commit()
            return 'Form submitted'
        else:
            return 'Form submission failed'

    # DELETE: Delete movie by movieId from the database
    @app.route('/delete-movie', methods=['GET', 'DELETE'])
    def delete_by_id():
        movie_id = request.form.to_dict()
        print(movie_id['movieId'])
        cur.execute(
            f"DELETE FROM movies WHERE movie_id = {movie_id['movieId']} RETURNING movie_name")
        con.commit()

        return 'Movie Deleted'

    # PUT: Update movie by movieId from the database
    @app.route('/update-movie', methods=['GET', 'PUT'])
    def update_by_id():

        cur.execute(
            'UPDATE movies SET movie_name = \'Goldeneye\' WHERE movie_id = 1')
        con.commit()

        return 'Movie Updated'

    # HarperDB Database routes

    # GET: Fetch all movies from the database
    @app.route('/harperdb')
    def harperdb_fetch_all():
        fetch_all = db._sql('SELECT * FROM dev.movies')
        print(fetch_all)
        return jsonify(fetch_all)

    # GET: Fetch movie by movieId from the database
    @app.route('/harperdb/<string:movie_id>')
    def harperdb_fetch_by_id(movie_id=None):
        # For fetching ID's that are numbers
        fetch_by_id = db._sql(
            f"SELECT * FROM dev.movies WHERE id = {movie_id}")

        # For fetching ID's that are strings
        # fetch_by_id = db._sql(
        #     f"SELECT * FROM dev.movies WHERE id = '{movie_id}'")
        print(fetch_by_id)
        return jsonify(fetch_by_id)

    # POST: Create movies and add them to the database
    @app.route('/harperdb/add-movie', methods=['GET', 'POST'])
    def harperdb_add_movie():
        if request.method == 'POST':
            data = request.form.to_dict()
            print(data)

            (f"{data['movieName']}", f"{data['imgUrl']}", data['releaseYear'], f"{data['summary']}",
             f"{data['director']}", f"{data['genre']}", f"{data['rating']}", data['movieRuntime'], data['metaScore'])
            add_new_movie = db._sql(
                f"INSERT INTO dev.movies(movie_name, img_url, release_year, summary, director, genre, rating, movie_runtime, meta_score) VALUES('{data['movieName']}', '{data['imgUrl']}', {data['releaseYear']}, '{data['summary']}', '{data['director']}', '{data['genre']}', '{data['rating']}', {data['movieRuntime']}, {data['metaScore']})")
            print(add_new_movie)
            return 'Form submitted'
        else:
            return 'Form submission failed'

    # DELETE: Delete movie by movieId from the database
    @app.route('/harperdb/delete-movie', methods=['GET', 'DELETE'])
    def harperdb_delete_by_id():
        movie_id = request.form.to_dict()
        print(movie_id['movieId'])
        # For fetching ID's that are numbers
        db._sql(
            f"DELETE FROM dev.movies WHERE id = {movie_id['movieId']}")

        # For fetching ID's that are strings
        # db._sql(
        #     f"DELETE FROM dev.movies WHERE id = '{movie_id['movieId']}'")

        return 'Movie Deleted'

    # PUT: Update movie by movieId from the database
    @app.route('/harperdb/update-movie', methods=['GET', 'PUT'])
    def harperdb_update_by_id():

        # For fetching ID's that are numbers
        db._sql(
            'UPDATE dev.movies SET movie_name = \'Goldeneye\' WHERE id = 7')

        # For fetching ID's that are strings
        # db._sql(
        #     f"UPDATE dev.movies SET movie_name = \'Goldeneye\' WHERE id = '42e7603f-f7ee-413d-9a0b-384ef04ca7de'")

        return 'Movie Updated'

except:
    print('Error')

```

Use your API tool or check out the routes in the browser to see the data returned as json from the HarperDB Database instance. HarperDB stores ID's as strings so please be aware that you won't be able to fetch, update and delete a movie by movieId if its ID is a number unless you make some adjustments to your code. We have been storing our ID's as numbers however it's easy to switch between the two I have commented out examples in the code.

You might need to restart you flask server if the routes don't work on the first try.

## Building the front end

It's time to create a front end that will get data back from the API. `cd` into the root folder for the meta-movies-app and then run the command below to set up a project in React.

```bash
npx create-react-app frontend
cd frontend
```

Now start the react app server using either `npm start` or `yarn start`

Navigate inside of your react project and then delete all of the css inside of the `index.css` file. Next replace the code inside of the `App.css` and `App.js` files with the code below.

**App.css**

```css
@import url('https://fonts.googleapis.com/css2?family=Arsenal:wght@400;700&display=swap');
* {
	padding: 0;
	margin: 0;
	box-sizing: border-box;
}

html {
	font-size: 62.5%;
}

body {
	font-size: 1.6rem;
	font-family: 'Arsenal', sans-serif;
	/* letter-spacing: 0.2rem; */
	background: rgb(242, 242, 242);
	color: #0e0e0e;
}

header {
	background: #0e0e0e;
	padding: 1rem;
}

header h1 {
	margin: 0 auto;
	text-align: center;
	text-transform: uppercase;
	color: #ffffff;
}

section {
	display: flex;
	flex-flow: row wrap;
	justify-content: space-evenly;
	margin: 4rem;
}

.form-container {
	margin: 2rem auto;
	width: 50rem;
	max-width: 100%;
	padding: 0 2rem 0 2rem;
}

form {
	display: flex;
	flex-flow: column;
}

form input {
	height: 3rem;
	padding: 1.5rem;
}

form textarea {
	padding: 1.5rem;
}

form button {
	padding: 1rem;
	border: none;
	background: #fcee0b;
	font-weight: bold;
	cursor: pointer;
	transition: background 0.3s;
	text-transform: uppercase;
}

form button:hover {
	background: rgb(243, 212, 35);
}

form div {
	display: flex;
	flex-flow: column;
	margin-bottom: 1.3rem;
}

.movie-container {
	background: #fcee0b;
	padding: 4rem;
	margin-top: 2rem;
	border-radius: 2rem 7rem;
	width: 50rem;
	max-width: 100%;
}

.movie-container h1 {
	font-size: 3rem;
}

.movie-container p {
	margin: 1rem 0 1rem 0;
	font-size: 2rem;
}

.movie-container img {
	width: 10rem;
	height: 15rem;
}

.high {
	background: #66cc32;
	width: 4rem;
	color: #ffffff;
	text-align: center;
	font-weight: 700;
	display: inline-block;
	padding: 0.5rem;
	border-radius: 1rem;
}

.medium {
	background: #ffcc32;
	width: 4rem;
	color: #ffffff;
	text-align: center;
	font-weight: 700;
	display: inline-block;
	padding: 0.5rem;
	border-radius: 1rem;
}

.low {
	background: #ff0100;
	width: 4rem;
	color: #ffffff;
	text-align: center;
	font-weight: 700;
	display: inline-block;
	padding: 0.5rem;
	border-radius: 1rem;
}

@media screen and (max-width: 1094px) {
	section {
		justify-content: center;
		/* margin: 0 auto; */
	}
}
```

**App.js**

```jsx
import React, { Fragment, useState, useEffect } from 'react';
import './App.css';

const App = () => {
	useEffect(() => {
		const getAPI = () => {
			// Change this endpoint to whatever local or online address you have
			// Local PostgreSQL Database
			const API = 'http://127.0.0.1:5000/';

			fetch(API)
				.then((response) => {
					console.log(response);
					return response.json();
				})
				.then((data) => {
					console.log(data);
					setLoading(false);
					setApiData(data);
				});
		};
		getAPI();
	}, []);
	const [apiData, setApiData] = useState([]);
	const [loading, setLoading] = useState(true);
	return (
		<Fragment>
			<header>
				<h1>Meta Movie Reviews</h1>
			</header>
			<div className="form-container">
				<h2>Add Movie</h2>
				<form method="POST" action="http://127.0.0.1:5000/add-movie">
					<div>
						<label>Movie Name</label>
						<input type="text" name="movieName" required />
					</div>
					<div>
						<label>Box Image</label>
						<input type="text" name="imgUrl" required />
					</div>
					<div>
						<label>Realease Year</label>
						<input type="text" name="releaseYear" required />
					</div>
					<div>
						<label>Summary</label>
						<textarea rows="5" cols="50" name="summary"></textarea>
					</div>
					<div>
						<label>Director</label>
						<input type="text" name="director" required />
					</div>
					<div>
						<label>Genre</label>
						<input type="text" name="genre" required />
					</div>
					<div>
						<label>Rating</label>
						<input type="text" name="rating" required />
					</div>
					<div>
						<label>Runtime</label>
						<input type="text" name="movieRuntime" required />
					</div>
					<div>
						<label>Meta Score</label>
						<input type="text" name="metaScore" required />
					</div>
					<div>
						<button type="submit">Add Movie</button>
					</div>
				</form>
			</div>
			<main>
				{loading === true ? (
					<div>
						<h1>Loading...</h1>
					</div>
				) : (
					<section>
						{apiData.map((movie) => {
							const movieId = movie[0];
							const movieName = movie[1];
							const movieImgUrl = movie[2];
							const movieReleaseYear = movie[3];
							const movieSummary = movie[4];
							const movieDirector = movie[5];
							const movieGenre = movie[6];
							const movieRating = movie[7];
							const movieRuntime = movie[8];
							const movieMetaScore = movie[9];

							let metaColor = 'low';

							if (movieMetaScore >= 70) {
								metaColor = 'high';
							} else if (movieMetaScore <= 69 && movieMetaScore >= 49) {
								metaColor = 'medium';
							} else {
								metaColor = 'low';
							}

							return (
								<div className="movie-container" key={String(movieId)}>
									<h1>{movieName}</h1>
									<p>
										<strong>Director:</strong> {movieDirector}
									</p>
									<p>
										<strong>Genre:</strong> {movieGenre}
									</p>
									<img src={movieImgUrl} alt={movieName} />

									<p>
										<strong>Meta Score:</strong> <span className={metaColor}>{movieMetaScore}</span>
									</p>
									<p>
										<strong>Runtime:</strong> {movieRuntime}
									</p>
									<p>
										<strong>Rating:</strong> {movieRating}
									</p>
									<p>
										<strong>Release Year:</strong> {movieReleaseYear}
									</p>
									<p>{movieSummary}</p>
								</div>
							);
						})}
					</section>
				)}
			</main>
		</Fragment>
	);
};

export default App;
```

Make sure that your Flask server is also running. You should see the app working inside of your browser. It also has a form that allows you to add new database entries which automatically get displayed on the page. Meta Scores are even colour coded depending on their number which is done using an if statement which you can see in the code.

The app is connected to your local PostgreSQL database however it is easy enough to change the endpoint for the API to HarperDB. All of the other routes are in the back end so you can play around with them and connect them to the front end which i'm sure you are already capable of doing.

When you add a new movie it does not redirect back to the react homepage. If you want to add this functionality then update your post route function in the backend `index.py` in the PostgreSQL section of the file with the code below.

```python
from flask import Flask, jsonify, request, redirect

# POST: Create movies and add them to the database
    @app.route('/add-movie', methods=['GET', 'POST'])
    def add_movie():
        if request.method == 'POST':
            data = request.form.to_dict()
            print(data)
            cur.execute("INSERT INTO movies (movie_name, img_url, release_year, summary, director, genre, rating, movie_runtime, meta_score) VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s)",
                        (f"{data['movieName']}", f"{data['imgUrl']}", data['releaseYear'], f"{data['summary']}",
                         f"{data['director']}", f"{data['genre']}", f"{data['rating']}", data['movieRuntime'], data['metaScore']))
            con.commit()
            # return 'Form submitted'
            return redirect('http://localhost:3000', code="200")
        else:
            return 'Form submission failed'
```