Enhancements to the popular file_column rails plugin by Sebastian Kanthak
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Modifications by Nikhil Gupte on top of original work done by Sebastian Kanthak.


This file_column plugin is based on the work done by Sebastian Kanthak. Refer to www.kanthak.net/opensource/file_column/ for the original file_column plugin. The following changes have been done in this version:

  1. In the original, all files were stored into one single folder per column. This would result in maxing out the limit of the number of sub-directories within a directory. This version addresses this problem by breaking up the sub-directories such that there will never be more than 101 sub-directories directly with a directory.

  2. Adds features to simplify integration with S3 to allow files to be moved/copied onto S3 in real time or in a batch mode.


Let's assume an model class named Entry, where we want to define the “image” column as a “file_upload” column.

class Entry < ActiveRecord::Base
  file_column :image
  • every entry can have one uploaded file, the filename will be stored in the “image” column

  • if the entry's id is 123, files will be stored in “public/entry/image/01/23/N123/TIMESTAMP.ext”

  • Newly uploaded files will be stored in “public/entry/tmp/<random>/TIMESTAMP.ext” so that they can be reused in form redisplays (due to validation etc.)

  • in a view, “<%= file_column_field 'entry', 'image' %> will create a file upload field as well as a hidden field to recover files uploaded before in a case of a form redisplay

  • in a view, “<%= url_for_file_column 'entry', 'image' %> will create an URL to access the uploaded file. Note that you need an Entry object in the instance variable @entry for this to work.

  • easy integration with RMagick to resize images and/or create thumb-nails.

  • easy integration with Amazon's S3 and CloudFront service.

  • if the move/copy to S3 fails, falls-back on the file system for storage

  • bulk batch-mode move/copy to S3 operations

  • generated dynamic filenames thus avoiding cache expiration issues when using Amazon CloudFront

S3 Integration

All files are first uploaded onto the file system, resized depending on the options provided, and finally moved (or copied) to S3. S3 integration is of two types: automatically move uploaded files to S3 once uploaded or move/copy the files using automatically generated class methods in a batch mode.

To integrate with S3, add a boolean column <attribute>_in_s3 to your model's table. For example: image_in_s3. This additional column is used to trac which files are present in S3 and which are on your local files system. When a file is uploaded the <attribute>_in_s3 is set to false. When that file is moved or copied onto S3, <attribute>_in_s3 changed to true.

class Entry < ActiveRecord::Base
  file_column :image, :s3 => true, :s3_auto => :move


  1. Install the right_aws gem

  2. Register with Amazon Web Services (S3 and optionally CloudFront)

  3. Enter the following config variables in your environment.rb file:

FileColumn::S3FileColumnExtension::Config.s3_access_key_id = YOUR_S3_ACCESS_KEY FileColumn::S3FileColumnExtension::Config.s3_secret_access_key = YOUR_S3_SECRET FileColumn::S3FileColumnExtension::Config.s3_bucket_name = THE_BUCKET_WHERE_THE_UPLOADED_FILE_SHOULD_BE_STORED FileColumn::S3FileColumnExtension::Config.s3_distribution_url = THE_S3_OR_CLOUD_FRONT_URL_OF_YOUR_BUCKET


  • s3 => true - If set, will add the following methods:

  • s3_auto => [:move | :copy] - Optional parameter which can be set to either of :move or :copy to automatically move/copy the uploaded files onto S3. If not specified, the files will remain on the file system till they are moved using one of the batch upload methods (described below).

Class Methods

The following Class methods are added to the class if the option :s3 => true is provided:

  • Entry.move_all_images_to_s3(options => {}) where options are the same as those used by regular finders

  • Entry.copy_all_images_to_s3(options => {}) where options are the same as those used by regular finders

Instance Methods

The following Instance methods are added if the option :s3 => true is provided:

  • @entry.move_image_to_s3

  • @entry.copy_image_to_s3


Just drop the whole directory into your application's “vendor/plugins” directory. Starting with version 1.0rc of rails, it will be automatically picked for you by rails plugin mechanism.


You can look at the rdoc-generated documentation in the “doc” directory for the original documentation. I'm still working on documenting the new features in detail.


Bug reports (as well as patches) and feedback are very welcome. Please send it to nikhilgupte_AT_gmail_DOT_com