Flask Interview Questions and Answers

Ques 1. How to add an emailing function in Flask?

Yes, we can add an emailing function in the Flask framework. Actually, we need to install the Flask-Mail extension. We can use the given below command:

Pip install Flask-Mail 

Now, after installation, we need to go to the Flask Config API. Under config, we will get Mail-Server, Mail_Port, Mail_username, Mail_Password, etc options. We can use the mail.send() method to compose the message.

from flask_mail import Mail,Message 
from flask import Flaskapp=Flask(_name_)
mail=Mail(app)
@app.route(\"/mail\")
def email():
  Msg=Message(\"Hello Message\",Sender=\"admin@test.com\",recipients=[\"to@test.com\"])
  Mail.send(msg)

Ques 2. Can we use the SQLite database in Flask?

Yes, it is built-in with Python as a database. We don’t have to install any extensions. Inside the Python view, we can import SQLite. There we can write SQL queries to interact with a database. Generally, the Python Flask developers use Flask-SQLAlchemy, which makes the SQL queries easier. It has one ORM, which helps to interact with the SQLite database.

Ques 3. Explain the thread-local Flask object?

Thread local Flask objects are mostly available in a valid request context. Because of this, we don’t need to pass objects from one method to another. Because in Flask thread safety is declared out of the box. We can access the objects by a command like the current _app.

Ques 4. How can we get a user agent in Flask?

We can use the request object, see the given below code:

From flask import Flask
From flask import request
app=Flask(_name_)
@app.route(“/”)
Def index():
  val=request.args.get(“var”)
  user_agent=request.headers.get(‘User-Agent’)
 response = """
     <p>
    Hello, World! {}
    <br/>
    You are accessing this app with {}
    </p>""".format(val, user_agent)
    return response

Hello, World!{}

you are accessing this app with {}

if_name_==”_main_”;            
app.run(host=”0.0.0.0”,port=8080)

Ques 5. How to use URLs in Flask?

We need to call the view function with parameters and give them values to generate URLs. Mainly Flask url_for the function we use here. It can also be used in Flask templates.

Ques 6. Explain the process of using the session in Flask?

The session is mainly used to store data in requests. We can store and get data from the session object in Flask. As shown below code we can try to do this:

From flask import Flask
sessionapp=Flask(_name_)
@app.route(‘/use_session’)
Def use_session():                 
  If ’song’ not in session;                 
    session[;songs’]={‘title’;’Tapestry’,’Bruno Major’}
  return session.get(‘songs’)

@app.route(‘/delete_session’)
def delete_session():                   
  session.pop(‘song’,None)                   
  return “removed song from session”

Ques 7. What is the procedure for database connection requests in Flask?

We can do it in three ways, they are:

1. after_request(): It helps make a request and passes the response, which will be sent to the client.
2. before-request(): It is called before the request without any argument passing.
3. teardown_request(): In case we get an exception, then this connection will be used and response is not guaranteed.