This Flask extension attempts to ease users' uploaded file encryption.
- PyCrypto (AES.MODE_CBC, AES.MODE_CFB) is used to encrypt/decrypt files
- Automatically rename and associate encrypted files
- Can be used to generate a download link and immediately delete the decrypted file
For now, for database side, it only support SQLAlchemy.
In order to work, flask-encryptor is based on these following modules:
- flask
- flask-sqlalchemy
- pycrypto
To install Flask-Encryptor, simply::
$ pip install flask-encryptorOr alternatively, you can download the repository and install manually by running::
$ git clone https://github.com/Querdos/Flask-Encryptor.git
$ cd Flask-Encryptor
$ python setup.py installLet's suppose we have simple Flask application with the following structure::
flask_app_test
|-- data
|-- template
|-- static
config.py
models.py
main.py
This flask extension concentrate on personal users files encryption, meaning that we will cover two part of a flask application. The user part and the file upload one. You will need to implement a user class (what attributes depend on what you need for your application), and UploadedFile and Token classes that both inherit (respectively) from BaseFile and BaseToken::
from main import db
from flask_encryptor.models import BaseFile, BaseToken
class UploadedFile(db.Model, BaseFile):
user_id = db.Column(db.Integer, db.ForeignKey('users.id'), nullable=False)
class Token(db.Model, BaseToken):
user_id = db.Column(db.Integer, db.ForeignKey('users.id'), nullable=False)
user = db.relationship('User', back_populates='token')
class User(db.Model):
__tablename__ = 'users'
# whatever attribute you want, such as username, password, etc...
uploaded_files = db.relationship('UploadedFile', backref='users', lazy=True)
token = db.relationship('Token', uselist=False, back_populates="user")Let's concentrate now on the main script, main.py. The initialization is quite simple with a few constants to set if needed:
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from flask_encryptor import FileEncryptor
# initializating the application
app = Flask(__name__)
# database configuration
app.config['SQLALCHEMY_DATABASE_URI'] = '...'
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
# initializing the database
db = SQLAlchemy(app)
# FileEncryptor configuration
# (Note that values here are default one)
app.config['FILE_ENCRYPTOR_CHUNK_SIZE'] = 64 * 1024
app.config['FILE_ENCRYPTOR_TMP_DIR'] = tempfile.mkdtemp(prefix='fencryptor_')
app.config['FILE_ENCRYPTOR_DATA_DIR'] = app.root_path+'/data/uploads'
app.config['FILE_ENCRYPTOR_GLOBAL_KEY'] = 'aAa8KxQx4Eoxwu41HTaa'
# initializing the file_encryptor object
file_encryptor = FileEncryptor(app, db)Details about constants :
| Constant | Description |
|---|---|
| FILE_ENCRYPTOR_CHUNK_SIZE | Chunk size that will be used for file encryption/decryption |
| FILE_ENCRYPTOR_TMP_DIR | Temporary folder that will be used to store decrypted files |
| FILE_ENCRYPTOR_DATA_DIR | Folder used to store encrypted file |
| FILE_ENCRYPTOR_GLOBAL_KEY | Global key used to encrypt file informations |
For this example, we are supposing to have three routes:
@app.route('/', methods=['GET', 'POST'])
def index_action():
# here we suppose that the form for uploading a file is in this route
if request.method == 'POST':
# checking that file parameter is in request form
if 'file' not in request.files:
flash('No file part', category='upload_errors')
return redirect(request.url)
# retrieving file object and checking that it is not empty
file = request.files['file']
if file.filename == '':
flash('No selected file', category='upload_errors')
return redirect(request.url)
# just send the file object to file_encryptor with the current user (here, optionnaly with
# flask_login extension, but you can query your database if you want)
infos = file_encryptor.upload_encrypt(file, current_user)
current_user.uploaded_files.append(UploadedFile(
filename=infos['filename'],
realname=infos['realname'],
path=app.config['FILE_ENCRYPTOR_DATA_DIR']
))
db.session.commit()
return redirect(request.url)
return render_template('index.html'), 200
@app.route('/upload/<upload_filename>', methods=['GET', 'POST'])
def uploaded_file_action(upload_filename):
# retrieving file in database
uploaded_file = UploadedFile.query.filter(UploadedFile.filename == filename).first()
# validation
if uploaded_file is None:
abort(400)
# decrypting the filename
filename = file_encryptor.decrypt_file(uploaded_file, current_user)
# sending file to the user
return send_from_directory(
directory = app.config['FILE_ENCRYPTOR_TMP_DIR'],
filename = filename,
as_attachment = True
)
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