A blobstore to store huge data objects in S3

blobstore.py

import simplejson
from boto.s3.connection import S3Connection
from boto.s3.key import Key
from boto.exception import S3ResponseError
AWS_ACCESS_KEY_ID = "xxx"
AWS_SECRET_ACCESS_KEY = "xxxxx"

class BlobStore(object):
    def __init__(self, bucket_name):
        s3_conn = S3Connection(AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY)
        self._bucket = s3_conn.get_bucket(bucket_name)
        self._key    = Key(self._bucket)

    def get_key(self, *args, **kwargs): raise Exception("Implement get_key on you BlobModel")

    def get(self, key, default=None):
        self._key.key = self.get_key(key)
        try:
            return simplejson.loads(self._key.get_contents_as_string())
        except S3ResponseError, err:
            if err.status == 404: return default
            raise err

    def set(self, key, value):
        self._key.key = self.get_key(key)
        if type(value) in [list, dict]: value = simplejson.dumps(value)
        return self._key.set_contents_from_string(value)

    def delete(self, key):
        return self._bucket.delete_key(self.get_key(key))


class MyNewDataBlob(BlobStore):
    def __init__(self):
        super(MyNewDataBlob, self).__init__("s3_bucket_name")

    def get_key(self, user_id): return "userdata:"+str(user_id)