Python API with Flask

• Install python from below link

        https://www.python.org/downloads/

        

• You can check if the python installation is success or not by running below command in command prompt

        python --version

• Then you have to set up the environment to run the python application. In command prompt run below command. Note that you have mention the python version

        py -2 -m pip install virtualenv

• Create a python file and name it as app.py
• Add below code as the first step and first sample API in the app.py file

    

• Now if you are added the environment properly you can see play icon in right side of the vs code. Click that and application will run on port 5000.

• Browse the url

• This will return the array as a html type (check network of inspect). If you want to return it as a json you want to change the code as below

• The result will be like below

• Now create a sample text file and insert sample json code. Define another route for the new API

    CRUD operation using MySQL

• Install MySQL library (you have to set the Script path of python in environmental variables to run the pip commands)

        pip install flask_mysqldb

• Import relevant libraries to the app.py

        from flask import Flask, render_template, request, jsonify         from flask_mysqldb import MySQL

• Now let's connect the database

        

• Just with the above set-up, we can’t interact with DB tables. For that, we need something called a cursor.
• To create the connection with cursor,

        cursor = mysql.connection.cursor()

• To create tables and run SQL queries,

        cursor.execute(''' CREATE TABLE table_name(field1, field2...) ''')         cursor.execute(''' INSERT INTO table_name VALUES(v1,v2...) ''')         cursor.execute(''' DELETE FROM table_name WHERE condition ''')

• To save the action performed in the Database,

        mysql.connection.commit()

• To close the cursor,

        cursor.close()

    Sample Login Application

• Create a table in MySQL called info_table
• Create a simple html page and design a form in it

• Connect the database and insert user data into the table using cursor in app.py

• Run the program and check

• We can do this operation using pymysql also. To do that import pymysql and make the connection. Then using cursor you can do run the queries you want.

• Well Done!!!