sqlalchemy-media 0.1.0.dev7

Sqlalchemy asset manager

Attaching any files(Image, Video & etc ) into sqlalchemy models using configurable stores including FileSystemStore.

See the documentation for full description.

Why ?

Nowadays, most of database applications are requested to allow users to upload and attach files with various types to ORM models.

Handling those jobs is not simple if you have to care about: Security, High-Availability, Scalability, CDN and more concerns you already taste those. Accepting a file from public space, analysing, validating, processing(Normalizing) and making it available to public space again. is the main goal of this project.

Sql-Alchemy is the best platform to implement these stuff on. It has the mutable types to manipulate the objects with any type in-place. why not ?

Overview

• Store and locate any file, track it by sqlalchemy models.

• Storage layer is completely separated from data model, with a simple api: (put, delete, open, locate)

• Using any SqlAlchemy type. This achieved by using the sqlalchemy type decorators.

• Using SqlAlchemy mutable.

• Offering delete_orphan flag, to automatically delete files which orphaned via attribute set or delete from collections, or objects leaved in memory alone! by setting it’s last pointer to None.

• Attaching files from Url, LocalFileSystem and Streams.

• Extracting the file’s mimetype from the backend stream if possible, using python’s built-in mimetypes module

• Limiting file size(min, max), to prevent DOS attacks.

• Adding timestamp in url to help caching.

Quick Start

Here a simple example to how to use this library:

import json
import functools
from os.path import join, exists

from sqlalchemy import Column, Integer, create_engine, Unicode, TypeDecorator
from sqlalchemy.orm import sessionmaker
from sqlalchemy.ext.declarative import declarative_base

from sqlalchemy_media import Image, StoreManager, FileSystemStore


TEMP_PATH = '/tmp/sqlalchemy-media'
Base = declarative_base()
engine = create_engine('sqlite:///:memory:', echo=False)


# Sqlite is not supporting JSON type, so emulating it:
class Json(TypeDecorator):
    impl = Unicode

    def process_bind_param(self, value, engine):
        return json.dumps(value)

    def process_result_value(self, value, engine):
        if value is None:
            return None

        return json.loads(value)


class Person(Base):
    __tablename__ = 'person'
    id = Column(Integer, primary_key=True)
    name = Column(Unicode(100))
    image = Column(Image.as_mutable(Json))

    def __repr__(self):
        return "<%s id=%s>" % (self.name, self.id)


Base.metadata.create_all(engine, checkfirst=True)
session_factory = sessionmaker(bind=engine)
StoreManager.register('fs', functools.partial(FileSystemStore, TEMP_PATH, 'http://static.example.org/'), default=True)

if __name__ == '__main__':
    session = session_factory()

    with StoreManager(session):
        person1 = Person()
        person1.image = Image.create_from('https://www.python.org/static/img/[e-mail]')
        session.add(person1)
        session.commit()
        print(person1.image)
        path = join(TEMP_PATH, person1.image.path)
        print(path)
        print(person1.image.locate())
        assert exists(path)

Will produces:

{'contentType': 'image/png',
 'extension': '.png',
 'key': '289bfb54-f90d-4a8a-b2c5-a4dd0fe7b647',
 'length': 15770,
 'originalFilename': 'https://www.python.org/static/img/[e-mail]',
 'timestamp': 1475445477.7994764}
'/tmp/sqlalchemy-media/images/image-289bfb54-f90d-4a8a-b2c5-a4dd0fe7b647-https://www.python.org/static/img/[e-mail]'
'http://static.example.org/images/image-289bfb54-f90d-4a8a-b2c5-a4dd0fe7b647-https://www.python.org/static/img/[e-mail]?_ts=1475445477.7994764'