22 KiB
CarrierWave
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.
Information
- RDoc documentation available on RubyDoc.info
- Source code available on GitHub
- More information, known limitations, and how-tos available on the wiki
Getting Help
- Please ask the Google Group for help if you have any questions.
- Please report bugs on the issue tracker but read the "getting help" section in the wiki first.
Installation
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.
Getting Started
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, including filesystem
and cloud storage.
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:
ActiveRecord
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 < ActiveRecord::Base
mount_uploader :avatar, AvatarUploader
end
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'
u.avatar.identifier # => 'file.png'
DataMapper, Mongoid, Sequel
Other ORM support has been extracted into separate gems:
There are more extensions listed in the wiki
Changing the storage directory
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.
Securing uploads
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
Filenames and unicode chars
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):
CarrierWave::SanitizedFile.sanitize_regexp = /[^[:word:]\.\-\+]/
With Ruby 1.8 you have to manually specify all character ranges. For example, for files which may contain Russian letters:
CarrierWave::SanitizedFile.sanitize_regexp = /[^a-zA-Zа-яА-ЯёЁ0-9\.\-\+_]/u
Also make sure that allowing non-latin characters won't cause a compatibility issue with a third-party plugins or client-side software.
Setting the content type
If you care about the content type of your files and notice that it's not being set
as expected, you can configure your uploaders to use CarrierWave::MimeTypes
.
This adds a dependency on the mime-types gem,
but is recommended when using fog, and fog already has a dependency on mime-types.
require 'carrierwave/processing/mime_types'
class MyUploader < CarrierWave::Uploader::Base
include CarrierWave::MimeTypes
process :set_content_type
end
Adding versions
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
Conditional versions
Occasionally you want to restrict the creation of versions on certain properties within the model or based on the picture itself.
class MyUploader < CarrierWave::Uploader::Base
version :human, :if => :is_human?
version :monkey, :if => :is_monkey?
version :banner, :if => :is_landscape?
protected
def is_human? picture
model.can_program?(:ruby)
end
def is_monkey? picture
model.favorite_food == 'banana'
end
def is_landscape? picture
image = MiniMagick::Image.open(picture.path)
image[:width] > image[:height]
end
end
The model
variable points to the instance object the uploader is attached to.
Create versions from existing versions
For performance reasons, it is often useful to create versions from existing ones instead of using the original file. If your uploader generates several versions where the next is smaller than the last, it will take less time to generate from a smaller, already processed image.
class MyUploader < CarrierWave::Uploader::Base
version :thumb do
process resize_to_fill: [280, 280]
end
version :small_thumb, :from_version => :thumb do
process resize_to_fill: [20, 20]
end
end
The option :from_version
uses the file cached in the :thumb
version instead
of the original version, potentially resulting in faster processing.
Making uploads work across form redisplays
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 %>
Removing uploaded files
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!
.
Uploading files from a remote location
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 %>
Providing a default URL
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
Recreating versions
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
Configuring CarrierWave
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 = :file
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
Testing with CarrierWave
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
@uploader.remove!
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
Setting the enable_processing flag on an uploader will prevent any of the versions from processing as well. Processing can be enabled for a single version by setting the processing flag on the version like so:
@uploader.thumb.enable_processing = true
Using Amazon S3
Fog is used to support Amazon S3. Ensure you have it in your Gemfile:
gem "fog", "~> 1.3.1"
You'll need to provide your fog_credentials and a fog_directory (also known as a bucket) in an initializer. For the sake of performance it is assumed that the directory already exists, so please create it if need be. You can also pass in additional options, as documented fully in lib/carrierwave/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.
Using Rackspace Cloud Files
Fog is used to support Rackspace Cloud Files. Ensure you have it in your Gemfile:
gem "fog", "~> 1.3.1"
You'll need to configure a directory (also known as a container), username and API key in the initializer. For the sake of performance it is assumed that the directory already exists, so please create it if need be.
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 = "http://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.
Using Google Storage for Developers
Fog is used to support Google Storage for Developers. Ensure you have it in your Gemfile:
gem "fog", "~> 1.3.1"
You'll need to configure a directory (also known as a bucket), access key id and secret access key in the initializer. For the sake of performance it is assumed that the directory already exists, so please create it if need be.
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.
Dynamic Fog Host
The fog_host
config property can be assigned a proc (or anything that responds to call
) for generating the host dynamically. The proc-compliant object gets an instance of the current CarrierWave::Storage::Fog::File
as its only argument.
CarrierWave.configure do |config|
config.fog_host = proc do |file|
identifier = # some logic
"http://#{identifier}.cdn.rackspacecloud.com"
end
end
Using RMagick
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.
There is a demonstration of convert here.
Convert will only work if the file has the same file extension, thus the use of the filename method.
class AvatarUploader < CarrierWave::Uploader::Base
include CarrierWave::RMagick
process :resize_to_fill => [200, 200]
process :convert => 'png'
def filename
super.chomp(File.extname(super)) + '.png'
end
end
Check out the manipulate! method, which makes it easy for you to write your own manipulation methods.
Using MiniMagick
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:
http://github.com/probablycorey/mini_magick
And the ImageMagick command line options for more for whats on offer:
http://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
Migrating from Paperclip
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.
i18n
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.'
Large files
By default, CarrierWave copies an uploaded file twice, first copying the file into the cache, then copying the file into the store. For large files, this can be prohibitively time consuming.
You may change this behavior by overriding either or both of the move_to_cache
and
move_to_store
methods:
class MyUploader < CarrierWave::Uploader::Base
def move_to_cache
true
end
def move_to_store
true
end
end
When the move_to_cache
and/or move_to_store
methods return true, files will be moved (instead of copied) to the cache and store respectively.
This has only been tested with the local filesystem store.
Contributing to CarrierWave
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.
License
Copyright (c) 2008-2012 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.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.