1. mgunneras
  2. django-storages


django-storages / backends / database.py

# DatabaseStorage for django.
# 2009 (c) GameKeeper Gambling Ltd, Ivanov E.

from django.core.files.storage import Storage
from django.core.files import File
from django.conf import settings

import StringIO
import urlparse

import pyodbc

class DatabaseStorage(Storage):
    Class DatabaseStorage provides storing files in the database. 

    def __init__(self, option=settings.DB_FILES):
        Constructs object using dictionary either specified in contucotr or
in settings.DB_FILES. 
        @param option dictionary with 'db_table', 'fname_column',
'blob_column', 'size_column', 'base_url'  keys. 
            Table to work with.
            Column in the 'db_table' containing filenames (filenames can
contain pathes). Values should be the same as where FileField keeps
            It is used to map filename to blob_column. In sql it's simply
used in where clause. 
            Blob column (for example 'image' type), created manually in the
'db_table', used to store image.
            Column to store file size. Used for optimization of size()
method (another way is to open file and get size)
            Url prefix used with filenames. Should be mapped to the view,
that returns an image as result. 
        if not option or not (option.has_key('db_table') and option.has_key('fname_column') and option.has_key('blob_column')
                              and option.has_key('size_column') and option.has_key('base_url') ):
            raise ValueError("You didn't specify required options")
        self.db_table = option['db_table']
        self.fname_column = option['fname_column']
        self.blob_column = option['blob_column']
        self.size_column = option['size_column']
        self.base_url = option['base_url']

        #get database settings
        self.DATABASE_NAME = settings.DATABASE_NAME
        self.DATABASE_USER = settings.DATABASE_USER
        self.DATABASE_HOST = settings.DATABASE_HOST
        self.connection = pyodbc.connect('DRIVER=%s;SERVER=%s;DATABASE=%s;UID=%s;PWD=%s'%(self.DATABASE_ODBC_DRIVER,self.DATABASE_HOST,self.DATABASE_NAME,
                                                                                          self.DATABASE_USER, self.DATABASE_PASSWORD) )
        self.cursor = self.connection.cursor()

    def _open(self, name, mode='rb'):
        """Open a file from database. 
        @param name filename or relative path to file based on base_url. path should contain only "/", but not "\". Apache sends pathes with "/".
        If there is no such file in the db, returs None
        assert mode == 'rb', "You've tried to open binary file without specifying binary mode! You specified: %s"%mode

        row = self.cursor.execute("SELECT %s from %s where %s = '%s'"%(self.blob_column,self.db_table,self.fname_column,name) ).fetchone()
        if row is None:
            return None
        inMemFile = StringIO.StringIO(row[0])
        inMemFile.name = name
        inMemFile.mode = mode
        retFile = File(inMemFile)
        return retFile

    def _save(self, name, content):
        """Save 'content' as file named 'name'.
        @note '\' in path will be converted to '/'. 
        name = name.replace('\\', '/')
        binary = pyodbc.Binary(content.read())
        size = len(binary)
        #todo: check result and do something (exception?) if failed.
        if self.exists(name):
            self.cursor.execute("UPDATE %s SET %s = ?, %s = ? WHERE %s = '%s'"%(self.db_table,self.blob_column,self.size_column,self.fname_column,name), 
                                 (binary, size)  )
            self.cursor.execute("INSERT INTO %s VALUES(?, ?, ?)"%(self.db_table), (name, binary, size)  )
        return name

    def exists(self, name):
        row = self.cursor.execute("SELECT %s from %s where %s = '%s'"%(self.fname_column,self.db_table,self.fname_column,name)).fetchone()
        return row is not None
    def get_available_name(self, name):
        return name

    def delete(self, name):
        if self.exists(name):
            self.cursor.execute("DELETE FROM %s WHERE %s = '%s'"%(self.db_table,self.fname_column,name))

    def url(self, name):
        if self.base_url is None:
            raise ValueError("This file is not accessible via a URL.")
        return urlparse.urljoin(self.base_url, name).replace('\\', '/')
    def size(self, name):
        row = self.cursor.execute("SELECT %s from %s where %s = '%s'"%(self.size_column,self.db_table,self.fname_column,name)).fetchone()
        if row is None:
            return 0
            return int(row[0])