How can I implement input validation in a Flask API?

How can I implement input validation in a Flask API?

You can use libraries like Marshmallow or Flask-WTF for input validation in Flask APIs. Would you like an example?

Yes, please provide an example using Marshmallow.

Sure! First, install Marshmallow with pip install marshmallow. Then, you can define a schema like this:

from marshmallow import Schema, fields

class UserSchema(Schema):
    username = fields.Str(required=True)
    email = fields.Email(required=True)

You can then use this schema to validate incoming data.

How do I handle validation errors?

You can catch validation errors by using the load method of the schema. It will raise a ValidationError if the data is invalid. You can handle it like this:

from marshmallow import ValidationError

try:
    user_data = UserSchema().load(request.json)
except ValidationError as err:
    return {'errors': err.messages}, 400