Flask request.form: Usage Guide

In Python, request.form is a dictionary used to retrieve form data passed through the HTTP POST method.

You can use request.form to retrieve the values ​​of the fields in the form. For example, assuming the form contains a field named username, you can use request.form[‘username’] to get the value of that field.

Here is a simple example:

from flask import Flask, request

app = Flask(__name__)

@app.route('/', methods=['GET', 'POST'])
def index():
    if request.method == 'POST':
        username = request.form['username']
        return f"Hello, {username}!"
    else:
        return "Please submit the form."

if __name__ == '__main__':
    app.run()

In the example above, if a POST request is received, retrieve the value of the username field from request.form and return a welcome message containing that value. If a GET request is received, return a message asking to submit the form.

It is important to note that when using request.form to retrieve form data, you need to ensure that the Content-Type of the request is application/x-www-form-urlencoded or multipart/form-data. Additionally, if a field does not exist, it will raise a KeyError exception, which can be avoided by using the get() method.

For more information about request.form, please refer to the Flask official documentation: https://flask.palletsprojects.com/en/2.0.x/api/?highlight=request.form#flask.Request.form