Mm-attach-it¶ ↑

Attach files (images, videos, pdfs, txts, zips and etc) to a MongoMapper record. You can even choose to store them on file system or GridFS.

sudo gem install mm-attach-it

Or add it to your Rails’s Gemfile

gem "mm-attach-it"

If you are using Mongo Mapper 0.8.x or later

gem "mm-attach-it", "~> 0.1.5"

Declare the plugin and use the attachment method to make attachments.

class Foo
  include MongoMapper::Document
  plugin AttachIt

  has_attachment :photo
end

The default storage destination is the file system, if you want to change it to GridFS you should add the following:

class Bar
  include MongoMapper::Document
  plugin AttachIt

  has_attachment :photo, { :storage => 'gridfs' }
end

If you want to resize the images (you can store resized images on both: file systems or GridFS):

class Foo
  include MongoMapper::Document
  plugin AttachIt

  has_attachment :photo, { :styles => { :small => '100x100>', :medium => '200x200>' } }
end

If you want to validate the attached file (again, you can validate attachments on both: file system or GridFS):

class Foo
  include MongoMapper::Document
  plugin AttachIt

  has_attch :photo

  validates_attachment_presence :photo
  validates_attachment_content_type :photo, :content_type => ['image/jpeg', 'image/gif', 'image/png']
  validates_attachment_size :photo, { :less_than => 1.megabyte, :greater_than => 500.kilobytes }
end

OBS: But remember! You can attach any desirable file.

If you are using the file system to store files, you can specify the directory/folder to store them.

class Foo
  include MongoMapper::Document
  plugin AttachIt

  has_attachment :photo, { :path => '/:rails_root/public/images/foos/:id/:style/:filename' }
end

OBS: The default directory is ’/:rails_root/public/system/:attachment/:id/:style/:filename’

Also you can interpolate any method result of the model

class Foo
  include MongoMapper::Document
  plugin AttachIt
  has_attachment :photo, { :url => '/:model.say_greet/users/:model.say_farewell/:id/:filename', :path => ':rails_root/public/:model.say_greet/:model.say_farewell/users/:id/:filename' }

  def say_greet
    'hello'
  end

  def say_farewell
    'bye'
  end
end

Where:

• :rails_root - is the root directory of your Rails application

• :environment - can be “production”, “test” or “development”

• :class - the name of the class (in the example given above, ‘foo’)

• :attachment - is the name of the column’s collection (in the example given above, ‘photo’)

• :id - the “id” of the record on MongoDB

• :style - if you specified the styles

• :filename - the name of the file

• :extension - the extension of the file

• :model.METHOD_NAME - where METHOD_NAME is any method of the model

Check the model below

class Foo
  include MongoMapper::Document
  plugin AttachIt

  # on file system
  has_attachment :photo, { 
    :styles => { :thumb => '100x100>' },
    :url => '/assets/groups/:id/:style/:filename', 
    :path => '/:rails_root/public/image/foos/:id/:style/:filename'
  }

  # on GridFS
  has_attachment :avatar, {
    :styles => { :thumb => '100x100>' }, 
    :storage => 'gridfs', 
  }
end

Within forms you must set the “multipart” option and the field as “file_field”:

<%= form_for(@foo, :html => { :multipart => true }) do |f| %>

  <p>
    <%= f.label :photo %>
    <%= f.file_field :photo %>
  </p>

  <p>
    <%= f.label :avatar %>
    <%= f.file_field :avatar %>
  </p>

  <div class="actions">
    <%= f.submit %>
  </div>
<% end %>

Regardless of using the file system or GridFS the safest way to present the images is using Base64.

<img src="<%= foo.photo.base64 %>">
<img src="<%= foo.photo.base64('thumb') %>">

<img src="<%= foo.avatar.base64 %>">
<img src="<%= foo.avatar.base64('thumb') %>">

Also, specifically when using the file system, if you specify the ‘url’ option, you can do:

<%= image_tag foo.photo.url %>
<%= image_tag foo.photo.url('thumb') %>

If you are using the GridFS to store files, and you don’t want to use Base64 data to present the images, you’ve got to create an action on a controller.

But first create a new route on the route’s file:

match '/foos/avatar/:id(/:style)', :to => 'foos#avatar'

Now the controller:

class FoosController < ApplicationController

  ...

  def avatar
    foo = Foo.where('_id' => BSON::ObjectId(params[:id])).first
    grid_io_data = (params[:style].nil?) ? foo.avatar.get_from_gridfs : foo.avatar.get_from_gridfs(params[:style])
    bytes = grid_io_data.read
    send_data(bytes, :type => foo.avatar_content_type, :disposition => 'inline')
  end

  ...

end

And, for the view, do that:

<%= image_tag  "/foos/avatar/#{foo.id.to_s}/small" %>

• Fork the project.

• Make your feature addition or bug fix.

• Add tests for it. This is important so I don’t break it in a future version unintentionally.

• Commit, do not mess with rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)

• Send me a pull request. Bonus points for topic branches.

Copyright © 2010 Adilson Chacon. See LICENSE for details.