Attachment_fu: Having problems with database_backend

First, Rick Olson - excellent plugin! Second, Mike Clark - excellent tutorial on file_system backend! Third, Ron Evans, excellent tutorial on database backend (http:// deadprogrammersociety.blogspot.com/2007/04/getting-your-attachmentfu- back-out-of.html)!

I am having serious trouble getting database storage working. I haven't found much information regarding using attachment_fu with a database backend, but I've almost got it working and have a strange bug.

It appears to be storing the entire file in the database, but when I pull it out and display it the image stops rendering after around 40K (haven't measured exactly where it cuts off, but files smaller than about 40k render and download completely). It is the same when I download the file, the downloaded file has the right dimensions, but the image only fills up part of the size of the original. The part filled in is sequential from the beginning. I am very confused.

The other alternative for me is to store the files on the file system, but they must be protected from direct download. These are confidential documents that I am uploading (driver's lisenses, birth certificates, social security cards, etc). Is there a way to protect the files from direct download and also allow them to be viewed and downloaded by logged in users (admins)?

Thanks, Peter

Are you sure your database isn't truncating the files?

Using the filesystem is usually better though. It's definitely faster and easier on memory (mongrel steams to a tmp file that you can just move, rather than opening it into memory).

For serving it, check out the x-accel-redirect header for nginx: http://wiki.codemongers.com/NginxXSendfile

In addition, you can avoid the penalty in your precious Rails processes delegating to the front-end server via the X-Sendfile header, there's a plugin that encapsulates that:

   http://agilewebdevelopment.com/plugins/xsendfile

Using that trick the flow becomes (think a regular Apache + Mongrel Cluster setup for example):

   1. Files are requested with URLs that point to some       controller instead of the public document root,       thus the controller has complete control about their       access according to the logic of the application

   2. The action resolves the filename to fetch somehow,       be careful with filenames, sanitize parameters, etc.

   3. It calls some of the plugin's send_file()-like methods,       which just add a header with the actual filename on       disk for the front-end server to handle

   4. The front-end server intercepts the response after       seeing the special header, and serves the file in its       value as if it was a regular public static file, it       takes care of the MIME type etc.

In development mode you don't need to use that necessarily, I use xsendfile's drop in replacement for send_file() only in production mode, it's as easy as throwing this line into environment.rb:

   XSendFile::Plugin.replace_send_file! if RAILS_ENV == 'production'

So that in development mode those files as always (for example by webrick), and in production the X-Sendfile stuff is activated without touching a single line of code.

-- fxn

In addition, you can avoid the penalty in your precious Rails processes delegating to the front-end server via the X-Sendfile header, there's a plugin that encapsulates that:

   http://agilewebdevelopment.com/plugins/xsendfile

Using that trick the flow becomes (think a regular Apache + Mongrel Cluster setup for example):

   1. Files are requested with URLs that point to some       controller instead of the public document root,       thus the controller has complete control about their       access according to the logic of the application

   2. The action resolves the filename to fetch somehow,       be careful with filenames, sanitize parameters, etc.

   3. It calls some of the plugin's send_file()-like methods,       which just add a header with the actual filename on       disk for the front-end server to handle

   4. The front-end server intercepts the response after       seeing the special header, and serves the file in its       value as if it was a regular public static file, it       takes care of the MIME type etc.

In development mode you don't need to use that necessarily, I use xsendfile's drop in replacement for send_file() only in production mode, it's as easy as throwing this line into environment.rb:

   XSendFile::Plugin.replace_send_file! if RAILS_ENV == 'production'

So that in development mode those files as always (for example by webrick), and in production the X-Sendfile stuff is activated without touching a single line of code.

-- fxn