WSGI concept overview in Flask - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a simple WSGI application function.

Flask

def application(environ, [1]):
    start_response('200 OK', [('Content-Type', 'text/plain')])
    return [b'Hello World']

Drag options to blanks, or click blank then click option'

Astart_response

Bsend_response

Crequest

Dresponse

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect argument names like 'response' or 'request' instead of 'start_response'.

Forgetting to include the 'start_response' argument.

The WSGI application function takes two arguments: environ and start_response. The start_response callable is used to begin the HTTP response.

2fill in blank

medium

Complete the code to call the start_response function with status and headers.

Flask

def application(environ, start_response):
    [1]('200 OK', [('Content-Type', 'text/html')])
    return [b'<h1>Welcome</h1>']

Drag options to blanks, or click blank then click option'

Asend_response

Bbegin_response

Cstart_response

Dresponse_start

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect function names like 'send_response' or 'begin_response'.

Not calling the function before returning the body.

The start_response function is called with the HTTP status and headers to begin the response.

3fill in blank

hard

Fix the error in the WSGI application to return the response body correctly as bytes.

Flask

def application(environ, start_response):
    start_response('200 OK', [('Content-Type', 'text/plain')])
    return [[1]]

Drag options to blanks, or click blank then click option'

A'Hello World'

Bb'Hello World'

Cbytearray('Hello World')

Dstr('Hello World')

Attempts:

3 left

💡 Hint

Common Mistakes

Returning a normal string instead of bytes.

Returning a non-iterable instead of a list or iterable.

The WSGI application must return an iterable of byte strings. Using b'Hello World' ensures the response is bytes.

4fill in blank

hard

Fill both blanks to create a Flask app and run it with debug mode on.

Flask

from flask import Flask
app = Flask(__name__)

@app.route('/')
def home():
    return 'Hello Flask!'

if __name__ == '__main__':
    app.[1](debug=[2])

Drag options to blanks, or click blank then click option'

Arun

Bstart

Cexecute

DTrue

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect method names like 'start' or 'execute'.

Setting debug to a string instead of a boolean.

To run a Flask app with debug mode, call app.run(debug=True).

5fill in blank

hard

Fill all three blanks to create a WSGI middleware that prints a message before calling the app.

Flask

def simple_middleware(app):
    def middleware(environ, start_response):
        print([1])
        return app([2], [3])
    return middleware

Drag options to blanks, or click blank then click option'

A'Middleware active'

Benviron

Cstart_response

D'Starting app'

Attempts:

3 left

💡 Hint

Common Mistakes

Passing wrong arguments to the app call.

Printing a variable instead of a string message.

The middleware prints a message, then calls the wrapped app with environ and start_response.