This gem provides a simple and extremely flexible way to upload files from Ruby applications. It works well with Rack based web applications, such as Ruby on Rails.
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RDoc documentation available on RubyDoc.info
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Source code available on GitHub
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More information, known limitations, and how-tos available on the wiki
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Please ask the Groogle Group for help if you have any questions.
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Please report bugs on the issue tracker but read the “getting help” section in the wiki first.
Install the latest stable release:
[sudo] gem install carrierwave
In Rails, add it to your Gemfile:
gem 'carrierwave'
Note that CarrierWave is not compatible with Rails 2 as of version 0.5. If you want to use Rails 2, please use the 0.4-stable branch on GitHub.
Start off by generating an uploader:
rails generate uploader Avatar
this should give you a file in:
app/uploaders/avatar_uploader.rb
Check out this file for some hints on how you can customize your uploader. It should look something like this:
class AvatarUploader < CarrierWave::Uploader::Base storage :file end
You can use your uploader class to store and retrieve files like this:
uploader = AvatarUploader.new uploader.store!(my_file) uploader.retrieve_from_store!('my_file.png')
CarrierWave gives you a store
for permanent storage, and a cache
for temporary storage. You can use different stores, at the moment a filesystem store, an Amazon S3 store, a Rackspace Cloud Files store, and a store for MongoDB’s GridFS are bundled.
Most of the time you are going to want to use CarrierWave together with an ORM. It is quite simple to mount uploaders on columns in your model, so you can simply assign files and get going:
Make sure you are loading CarrierWave after loading your ORM, otherwise you’ll need to require the relevant extension manually, e.g.:
require 'carrierwave/orm/activerecord'
Add a string column to the model you want to mount the uploader on:
add_column :users, :avatar, :string
Open your model file and mount the uploader:
class User mount_uploader :avatar, AvatarUploader end
This works the same with all supported ORMs.
Now you can cache files by assigning them to the attribute, they will automatically be stored when the record is saved.
u = User.new u.avatar = params[:file] u.avatar = File.open('somewhere') u.save! u.avatar.url # => '/url/to/file.png' u.avatar.current_path # => 'path/to/file.png'
If using DataMapper, make sure to disable auto_validation on the mounted column.
If using Mongoid, note that embedded documents files aren’t saved when parent documents are saved. You must explicitly call save on embedded documents in order to save their attached files. You can read more about this here
In order to change where uploaded files are put, just override the store_dir
method:
class MyUploader < CarrierWave::Uploader::Base def store_dir 'public/my/upload/directory' end end
This works for the file storage as well as Amazon S3 and Rackspace Cloud Files. Define store_dir
as nil
if you’d like to store files at the root level.
Certain file might be dangerous if uploaded to the wrong location, such as php files or other script files. CarrierWave allows you to specify a white-list of allowed extensions.
If you’re mounting the uploader, uploading a file with the wrong extension will make the record invalid instead. Otherwise, an error is raised.
class MyUploader < CarrierWave::Uploader::Base def extension_white_list %w(jpg jpeg gif png) end end
Another security issue you should care for is the file names (see Ruby On Rails Security Guide). By default, CarrierWave provides only English letters, arabic numerals and ‘-+_.’ symbols as white-listed characters in the file name.
If you want to support local scripts (Cyrillic letters, letters with diacritics and so on), you have to override sanitize_regexp
method. It should return regular expression which would match all non-allowed symbols.
With Ruby 1.9 and higher you can simply write (as it has Oniguruma built-in):
class MyUploader < CarrierWave::Uploader::Base def sanitize_regexp /[^[:word:]\.\-\+]/ end end
With Ruby 1.8.* you have to manually specify all character ranges. For example, for files which may contain Russian letters:
class MyUploader < CarrierWave::Uploader::Base def sanitize_regexp /[^a-zA-Zа-яА-ЯёЁ0-9\.\-\+_]/u end end
Also make sure that allowing non-latin characters won’t cause a compatibility issue with a third-party plugins or client-side software.
Often you’ll want to add different versions of the same file. The classic example is image thumbnails. There is built in support for this:
class MyUploader < CarrierWave::Uploader::Base include CarrierWave::RMagick process :resize_to_fit => [800, 800] version :thumb do process :resize_to_fill => [200,200] end end
When this uploader is used, an uploaded image would be scaled to be no larger than 800 by 800 pixels. A version called thumb is then created, which is scaled and cropped to exactly 200 by 200 pixels. The uploader could be used like this:
uploader = AvatarUploader.new uploader.store!(my_file) # size: 1024x768 uploader.url # => '/url/to/my_file.png' # size: 800x600 uploader.thumb.url # => '/url/to/thumb_my_file.png' # size: 200x200
One important thing to remember is that process is called before versions are created. This can cut down on processing cost.
It is possible to nest versions within versions:
class MyUploader < CarrierWave::Uploader::Base version :animal do version :human version :monkey version :llama end end
Often you’ll notice that uploaded files disappear when a validation fails. CarrierWave has a feature that makes it easy to remember the uploaded file even in that case. Suppose your user
model has an uploader mounted on avatar
file, just add a hidden field called avatar_cache
. In Rails, this would look like this:
<%= form_for @user, :html => {:multipart => true} do |f| %> <p> <label>My Avatar</label> <%= f.file_field :avatar %> <%= f.hidden_field :avatar_cache %> </p> <% end %>
It might be a good idea to show the user that a file has been uploaded, in the case of images, a small thumbnail would be a good indicator:
<%= form_for @user, :html => {:multipart => true} do |f| %> <p> <label>My Avatar</label> <%= image_tag(@user.avatar_url) if @user.avatar? %> <%= f.file_field :avatar %> <%= f.hidden_field :avatar_cache %> </p> <% end %>
If you want to remove a previously uploaded file on a mounted uploader, you can easily add a checkbox to the form which will remove the file when checked.
<%= form_for @user, :html => {:multipart => true} do |f| %> <p> <label>My Avatar</label> <%= image_tag(@user.avatar_url) if @user.avatar? %> <%= f.file_field :avatar %> </p> <p> <label> <%= f.check_box :remove_avatar %> Remove avatar </label> </p> <% end %>
If you want to remove the file manually, you can call remove_avatar!
.
Your users may find it convenient to upload a file from a location on the Internet via a URL. CarrierWave makes this simple, just add the appropriate attribute to your form and you’re good to go:
<%= form_for @user, :html => {:multipart => true} do |f| %> <p> <label>My Avatar URL:</label> <%= image_tag(@user.avatar_url) if @user.avatar? %> <%= f.text_field :remote_avatar_url %> </p> <% end %>
In many cases, especially when working with images, it might be a good idea to provide a default url, a fallback in case no file has been uploaded. You can do this easily by overriding the default_url
method in your uploader:
class MyUploader < CarrierWave::Uploader::Base def default_url "/images/fallback/" + [version_name, "default.png"].compact.join('_') end end
You might come to a situation where you want to retroactively change a version or add a new one. You can use the recreate_versions! method to recreate the versions from the base file. This uses a naive approach which will re-upload and process all versions.
instance = MyUploader.new instance.recreate_versions!
Or on a mounted uploader:
User.all.each do |user| user.avatar.recreate_versions! end
CarrierWave has a broad range of configuration options, which you can configure, both globally and on a per-uploader basis:
CarrierWave.configure do |config| config.permissions = 0666 config.storage = :s3 end
Or alternatively:
class AvatarUploader < CarrierWave::Uploader::Base permissions 0777 end
If you’re using Rails, create an initializer for this:
config/initializers/carrierwave.rb
It’s a good idea to test you uploaders in isolation. In order to speed up your tests, it’s recommended to switch off processing in your tests, and to use the file storage. In Rails you could do that by adding an initializer with:
if Rails.env.test? or Rails.env.cucumber? CarrierWave.configure do |config| config.storage = :file config.enable_processing = false end end
If you need to test your processing, you should test it in isolation, and enable processing only for those tests that need it.
CarrierWave comes with some RSpec matchers which you may find useful:
require 'carrierwave/test/matchers' describe MyUploader do include CarrierWave::Test::Matchers before do MyUploader.enable_processing = true @uploader = MyUploader.new(@user, :avatar) @uploader.store!(File.open(path_to_file)) end after do MyUploader.enable_processing = false end context 'the thumb version' do it "should scale down a landscape image to be exactly 64 by 64 pixels" do @uploader.thumb.should have_dimensions(64, 64) end end context 'the small version' do it "should scale down a landscape image to fit within 200 by 200 pixels" do @uploader.small.should be_no_larger_than(200, 200) end end it "should make the image readable only to the owner and not executable" do @uploader.should have_permissions(0600) end end
Fog is used to support Amazon S3. Ensure you have it installed:
gem install fog
You’ll need to provide your fog_credentials and a fog_directory (also known as a bucket) in an initializer. You can also pass in additional options, as documented fully in lib/storage/fog.rb. Here’s a full example:
CarrierWave.configure do |config| config.fog_credentials = { :provider => 'AWS', # required :aws_access_key_id => 'xxx', # required :aws_secret_access_key => 'yyy', # required :region => 'eu-west-1' # optional, defaults to 'us-east-1' } config.fog_directory = 'name_of_directory' # required config.fog_host = 'https://assets.example.com' # optional, defaults to nil config.fog_public = false # optional, defaults to true config.fog_attributes = {'Cache-Control'=>'max-age=315576000'} # optional, defaults to {} end
In your uploader, set the storage to :fog
class AvatarUploader < CarrierWave::Uploader::Base storage :fog end
That’s it! You can still use the CarrierWave::Uploader#url
method to return the url to the file on Amazon S3.
Fog is used to support Rackspace Cloud Files. Ensure you have it installed:
gem install fog
You’ll need to configure a directory (also known as a container), username and api key like this in an initializer:
CarrierWave.configure do |config| config.fog_credentials = { :provider => 'Rackspace', :rackspace_username => 'xxxxxx', :rackspace_api_key => 'yyyyyy' } config.fog_directory = 'name_of_directory' end
You can optionally include your CDN host name in the configuration. This is highly recommended, as without it every request requires a lookup of this information.
config.fog_host = "c000000.cdn.rackspacecloud.com"
In your uploader, set the storage to :fog
class AvatarUploader < CarrierWave::Uploader::Base storage :fog end
That’s it! You can still use the CarrierWave::Uploader#url
method to return the url to the file on Rackspace Cloud Files.
Fog is used to support Google Storage for Developers. Ensure you have it installed:
gem install fog
You’ll need to configure a directory (also known as a bucket), access key id and secret access key like this in an initializer:
CarrierWave.configure do |config| config.fog_credentials = { :provider => 'Google', :google_storage_access_key_id => 'xxxxxx', :google_storage_secret_access_key => 'yyyyyy' } config.fog_directory = 'name_of_directory' end
In your uploader, set the storage to :fog
class AvatarUploader < CarrierWave::Uploader::Base storage :fog end
That’s it! You can still use the CarrierWave::Uploader#url
method to return the url to the file on Google.
You’ll need to configure the database and host to use:
CarrierWave.configure do |config| config.grid_fs_database = 'my_mongo_database' config.grid_fs_host = 'mongo.example.com' end
The defaults are ‘carrierwave’ and ‘localhost’.
And then in your uploader, set the storage to :grid_fs
:
class AvatarUploader < CarrierWave::Uploader::Base storage :grid_fs end
Since GridFS doesn’t make the files available via HTTP, you’ll need to stream them yourself. In Rails for example, you could use the send_data
method. You can tell CarrierWave the URL you will serve your images from, allowing it to generate the correct URL, by setting eg:
CarrierWave.configure do |config| config.grid_fs_access_url = "/image/show" end
If you’re uploading images, you’ll probably want to manipulate them in some way, you might want to create thumbnail images for example. CarrierWave comes with a small library to make manipulating images with RMagick easier, you’ll need to include it in your Uploader:
class AvatarUploader < CarrierWave::Uploader::Base include CarrierWave::RMagick end
The RMagick module gives you a few methods, like CarrierWave::RMagick#resize_to_fill
which manipulate the image file in some way. You can set a process
callback, which will call that method any time a file is uploaded.
class AvatarUploader < CarrierWave::Uploader::Base include CarrierWave::RMagick process :resize_to_fill => [200, 200] process :convert => 'png' def filename super + '.png' end end
Check out the manipulate! method, which makes it easy for you to write your own manipulation methods.
ImageScience works the same way as RMagick.
class AvatarUploader < CarrierWave::Uploader::Base include CarrierWave::ImageScience process :resize_to_fill => [200, 200] end
MiniMagick is similar to RMagick but performs all the operations using the ‘mogrify’ command which is part of the standard ImageMagick kit. This allows you to have the power of ImageMagick without having to worry about installing all the RMagick libraries.
See the MiniMagick site for more details:
github.com/probablycorey/mini_magick
And the ImageMagick command line options for more for whats on offer:
www.imagemagick.org/script/command-line-options.php
Currently, the MiniMagick carrierwave processor provides exactly the same methods as for the RMagick processor.
class AvatarUploader < CarrierWave::Uploader::Base include CarrierWave::MiniMagick process :resize_to_fill => [200, 200] end
If you are using Paperclip, you can use the provided compatibility module:
class AvatarUploader < CarrierWave::Uploader::Base include CarrierWave::Compatibility::Paperclip end
See the documentation for CarrierWave::Compatibility::Paperclip
for more details.
Be sure to use mount_on to specify the correct column:
mount_uploader :avatar, AvatarUploader, :mount_on => :avatar_file_name
Unfortunately attachment_fu differs too much in philosophy for there to be a sensible compatibility mode. Patches for migrating from other solutions will be happily accepted.
The Active Record validations use the Rails i18n framework. Add these keys to your translations file:
errors: messages: carrierwave_processing_error: 'Cannot resize image.' carrierwave_integrity_error: 'Not an image.'
CarrierWave thrives on a large number of contributors, and pull requests are very welcome. Before submitting a pull request, please make sure that your changes are well tested.
You’ll need to install bundler and the gem dependencies:
gem install bundler bundle install
You should now be able to run the local tests:
bundle exec rake
You can also run the remote specs by creating a ~/.fog file:
:carrierwave: :aws_access_key_id: xxx :aws_secret_access_key: yyy :rackspace_username: xxx :rackspace_api_key: yyy :google_storage_access_key_id: xxx :google_storage_secret_access_key: yyy
You should now be able to run the remote tests:
REMOTE=true bundle exec rake
Please test with the latest Ruby 1.8.x and 1.9.x versions using RVM if possible.
Copyright © 2008 Jonas Nicklas
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
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