# Refile
[](http://badge.fury.io/rb/refile)
[](https://travis-ci.org/refile/refile)
[](http://inch-ci.org/github/refile/refile)
Refile is a modern file upload library for Ruby applications. It is simple, yet
powerful.
Links:
- [API documentation](http://www.rubydoc.info/gems/refile)
- [Source Code](https://github.com/refile/refile)
- [Contributing](https://github.com/refile/refile/blob/master/CONTRIBUTING.md)
- [Code of Conduct](https://github.com/refile/refile/blob/master/CODE_OF_CONDUCT.md)
- [Example Application](https://github.com/refile/refile_example_app)
Features:
- Configurable backends, file system, S3, etc...
- Convenient integration with ORMs
- On the fly manipulation of images and other files
- Streaming IO for fast and memory friendly uploads
- Works across form redisplays, i.e. when validations fail, even on S3
- Effortless direct uploads, even to S3
- Support for multiple file uploads
- Support for single file upload
Sponsored by:
[<img src="http://d3cv91luii1z1d.cloudfront.net/logo-gh.png" alt="Elabs" height="50px"/>](http://elabs.se)
## Quick start, Rails
Add the gem:
``` ruby
gem "refile", require: "refile/rails"
gem "refile-mini_magick"
```
We're requiring both Refile's Rails integration and image processing via the
[MiniMagick](https://github.com/minimagick/minimagick) gem, which requires
[ImageMagick](http://imagemagick.org/) (or [GraphicsMagick](http://www.graphicsmagick.org/)) to be installed. To install it simply
run:
``` sh
brew install imagemagick # OS X
sudo apt-get install imagemagick # Ubuntu
```
Use the `attachment` method to use Refile in a model:
``` ruby
class User < ActiveRecord::Base
attachment :profile_image
end
```
Generate a migration:
``` sh
rails generate migration add_profile_image_to_users profile_image_id:string &&
profile_image_filename:string && profile_image_size:string &&
profile_image_content_type:string
rake db:migrate
```
Add an attachment field to your form:
``` erb
<%= form_for @user do |form| %>
<%= form.attachment_field :profile_image %>
<% end %>
```
Set up strong parameters:
``` ruby
def user_params
params.require(:user).permit(:profile_image)
end
```
And start uploading! Finally show the file in your view:
``` erb
<%= image_tag attachment_url(@user, :profile_image, :fill, 300, 300, format: "jpg") %>
```
## How it works
Refile consists of several parts:
1. Backends: cache and persist files
2. Model attachments: map files to model columns
3. A Rack application: streams files and accepts uploads
4. Rails helpers: conveniently generate markup in your views
5. A JavaScript library: facilitates direct uploads
Let's look at each of these in more detail!
## 1. Backend
Files are uploaded to a backend. The backend assigns an ID to this file, which
will be unique for this file within the backend.
Let's look at a simple example of using the backend:
``` ruby
backend = Refile::Backend::FileSystem.new("tmp")
file = backend.upload(StringIO.new("hello"))
file.id # => "b205bc..."
file.read # => "hello"
backend.get(file.id).read # => "hello"
```
As you may notice, backends are "flat". Files do not have directories, nor do
they have names or permissions, they are only identified by their ID.
Refile has a global registry of backends, accessed through `Refile.backends`.
There are two "special" backends, which are only really special in that they
are the default backends for attachments. They are `cache` and `store`.
By default files will be uploaded to `./tmp/uploads/store`. If you would like
to persist them between deploys of your application, you can override the upload
folder by adding an initializer like this:
```ruby
# config/initializers/refile.rb
Refile.backends['store'] = Refile::Backend::FileSystem.new('/etc/projectname-uploads/')
```
The cache is intended to be transient. Files are added here before they are
meant to be permanently stored. Usually files are then moved to the store for
permanent storage, but this isn't always the case.
Suppose for example that a user uploads a file in a form and receives a
validation error. In that case the file has been temporarily stored in the
cache. The user might decide to fix the error and resubmit, at which point the
file will be promoted to the store. On the other hand, the user might simply
give up and leave, now the file is left in the cache for later cleanup.
Refile has convenient accessors for setting the `cache` and `store`, so for
example if you add the refile-s3 gem to your Gemfile:
``` ruby
gem "refile-s3"
```
Now you can upload files to S3 easily by using these accessors:
``` ruby
# config/initializers/refile.rb
require "refile/s3"
aws = {
access_key_id: "xyz",
secret_access_key: "abc",
region: "sa-east-1",
bucket: "my-bucket",
}
Refile.cache = Refile::S3.new(prefix: "cache", **aws)
Refile.store = Refile::S3.new(prefix: "store", **aws)
```
Try this in the quick start example above and your files are now uploaded to
S3.
Backends also provide the option of restricting the size of files they accept.
For example:
``` ruby
Refile.cache = Refile::S3.new(max_size: 10.megabytes, ...)
```
The Refile gem only ships with a
[FileSystem](lib/refile/backend/file_system.rb) backend. Additional backends
are provided by other gems.
- [Amazon S3](https://github.com/refile/refile-s3)
- [Fog](https://github.com/refile/refile-fog) provides support for a ton of
different cloud storage providers, including Google Storage and Rackspace
CloudFiles.
- [Postgresql](https://github.com/krists/refile-postgres)
- [Gridfs](https://github.com/Titinux/refile-gridfs)
- [In Memory](https://github.com/refile/refile-memory)
### Uploadable
The `upload` method on backends can be called with a variety of objects. It
requires that the object passed to it behaves similarly to Ruby IO objects, in
particular it must implement the methods `size`, `read(length = nil, buffer =
nil)`, `eof?`, `rewind`, and `close`. All of `File`, `Tempfile`,
`ActionDispatch::UploadedFile` and `StringIO` implement this interface, however
`String` does not. If you want to upload a file from a `String` you must wrap
it in a `StringIO` first.
## 2. Attachments
You've already seen the `attachment` method:
``` ruby
class User < ActiveRecord::Base
attachment :profile_image
end
```
Calling `attachment` generates a getter and setter with the given name. When
you assign a file to the setter, it is uploaded to the cache:
``` ruby
User.new
# with a ActionDispatch::UploadedFile
user.profile_image = params[:file]
# with a regular File object
File.open("/some/path", "rb") do |file|
user.profile_image = file
end
# or a StringIO
user.profile_image = StringIO.new("hello world")
user.profile_image.id # => "fec421..."
user.profile_image.read # => "hello world"
```
When you call `save` on the record, the uploaded file is transferred from the
cache to the store. Where possible, Refile does this move efficiently. For example
if both `cache` and `store` are on the same S3 account, instead of downloading
the file and uploading it again, Refile will simply issue a copy command to S3.
### Other ORMs
Refile comes with [ActiveRecord
integration](lib/refile/attachment/active_record.rb) built-in, but is built to
integrate with any ORM, so building your own should not be too difficult. Some
integrations are already available via gems:
* [refile-sequel](https://github.com/refile/refile-sequel)
* [refile-mongoid](https://github.com/krettan/refile-mongoid)
### Pure Ruby classes
You can also use attachments in pure Ruby classes like this:
``` ruby
class User
extend Refile::Attachment
attr_accessor :profile_image_id
attachment :profile_image
end
```
### Keeping uploaded files
By default Refile will delete a stored file when its model is destroyed. You can change this behaviour by passing in the `destroy` option.
```ruby
class User < ActiveRecord::Base
attachment :profile_image, destroy: false
end
```
Now Refile will not delete the `profile_image` file from the store if the user is destroyed.
## 3. Rack Application
Refile includes a Rack application (an endpoint, not a middleware), written in
Sinatra. This application streams files from backends and can even accept file
uploads and upload them to backends.
**Important:** Unlike other file upload solutions, Refile always streams your files through your
application. It cannot generate URLs to your files. This means that you should
**always** put a CDN or other HTTP cache in front of your application. Serving
files through your app takes a lot of resources and you want it to happen rarely.
Setting this up is actually quite simple, you can use the same CDN you would use
for your application's static assets. [This blog post](http://www.happybearsoftware.com/use-cloudfront-and-the-rails-asset-pipeline-to-speed-up-your-app.html)
explains how to set this up (bonus: faster static assets!). Once you've set this
up, simply configure Refile to use your CDN:
``` ruby
Refile.cdn_host = "https://your-dist-url.cloudfront.net"
```
Using [the HTTPS protocol](https://www.eff.org/encrypt-the-web-report) for `Refile.cdn_host` is recommended. There aren't [any performance concerns](https://istlsfastyet.com/), and it is always safe to request HTTPS assets.
### Mounting
If you are using Rails and have required [refile/rails.rb](lib/refile/rails.rb),
then the Rack application is mounted for you at `/attachments`. You should be able
to see this when you run `rake routes`.
You can configure Refile to use a different `mount_point` than `/attachments`:
``` ruby
Refile.mount_point = "/your-preferred-mount-point"
```
You could also run the application on its own, it doesn't need to be mounted to
work.
If you are using a catch-all route (such as required by Comfy CMS), you will need to turn off Automounting and add the refile route before your catch all route.
(in initializers/refile.rb)
``` ruby
Refile.automount = false
```
in routes.rb
``` ruby
mount Refile.app, at: Refile.mount_point, as: :refile_app
# Make sure this routeset is defined last
comfy_route :cms, :path => '/', :sitemap => true
```
### Retrieving files
Files can be retrieved from the application by calling:
```
GET /attachments/:token/:backend_name/:id/:filename
```
The `:filename` serves no other purpose than generating a nice name when the user
downloads the file, it does not in any way affect the downloaded file. For caching
purposes you should always use the same filename for the same file. The Rails helpers
default this to the name of the column.
The `:token` is a generated digest of the request path when the
`Refile.secret_key` is configured; otherwise, the application will raise an error.
The digest feature provides a security measure against unverified requests.
**NOTICE:** If you don't set the `Refile.secret_key` we will use rails `secret_key_base`
to generate the token. We suggest you not to change the `secret_key_base` after you
generated and hardcoded some attachment URLs in your application (e.g. blog post images),
because the token will change and you'll not be able to retrieve in this case, the images.
### Processing
Refile provides on the fly processing of files. You can trigger it by calling
a URL like this:
```
GET /attachments/:token/:backend_name/:processor_name/*args/:id/:filename
```
Suppose we have uploaded a file:
``` ruby
Refile.cache.upload(StringIO.new("hello")).id # => "a4e8ce"
```
And we've defined a processor like this:
``` ruby
Refile.processor :reverse do |file|
StringIO.new(file.read.reverse)
end
```
Then you could do the following.
``` sh
curl http://127.0.0.1:3000/attachments/token/cache/reverse/a4e8ce/some_file.txt
elloh
```
Refile calls `call` on the processor and passes in the retrieved file, as well
as all additional arguments sent through the URL.
## 4. Rails helpers
Refile provides the `attachment_field` form helper which generates a file field
as well as a hidden field. This field keeps track of the file in case it is not
yet permanently stored, for example if validations fail. It is also used for
direct and presigned uploads. For this reason it is highly recommended to use
`attachment_field` instead of `file_field`.
``` erb
<%= form_for @user do |form| %>
<%= form.attachment_field :profile_image %>
<% end %>
```
Will generate something like:
``` html
<form action="/users" enctype="multipart/form-data" method="post">
<input name="user[profile_image]" type="hidden">
<input name="user[profile_image]" type="file">
</form>
```
The `attachment_url` helper can then be used for generating URLs for the uploaded
files:
``` erb
<%= link_to "Image", attachment_url(@user, :profile_image) %>
```
Any additional arguments to it are included in the URL as processor arguments:
``` erb
<%= link_to "Image", attachment_url(@user, :profile_image, :fill, 300, 300) %>
```
There's also a helper for generating image tags:
``` erb
<%= attachment_image_tag(@user, :profile_image, :fill, 300, 300) %>
```
You can also provide a limit to the image:
``` erb
<%= link_to "Image", attachment_url(@user, :profile_image, :limit, 400, 500) %>
```
If you don't care about the aspect ratio and want an exact dimension, you can use `!`:
``` erb
<%= link_to "Image", attachment_url(@user, :profile_image, :limit, 400, "1000!") %>
```
Keep in mind that it's also important to remember you can not stretch the image, even you set
a larger width or height the image will keep its default dimensions. For example: if you set
`400x1000!` for an image `600x800` it'll keep its height of `400x800`.
If you just care about limit only one dimension, you can use `nil` in widht or height:
``` erb
<%= link_to "Image", attachment_url(@user, :profile_image, :limit, 400, nil) %>
<%= link_to "Image", attachment_url(@user, :profile_image, :limit, nil, 400) %>
```
With this helper you can specify an image/asset which is used as a fallback in case
no file has been uploaded:
``` erb
<%= attachment_url(@user, :profile_image, :fill, 300, 300, fallback: "default.png") %>
<%= attachment_image_tag(@user, :profile_image, :fill, 300, 300, fallback: "default.png") %>
```
You can also set the URL to force the download of the uploaded file:
``` erb
<%= link_to "Download", attachment_url(@user, :profile_image, force_download: true) %>
```
Use `Refile.attachment_url` if you already have `attachment` in your routes.
## 5. JavaScript library
Refile's JavaScript library is small but powerful.
Uploading files is slow, so anything we can do to speed up the process is going
to lead to happier users. One way to cheat is to start uploading files directly
after the user has chosen a file, instead of waiting until they hit the submit
button. This provides a significantly better user experience. Implementing this
is usually tricky, but thankfully Refile makes it very easy.
First, load the JavaScript file. If you're using the asset pipeline, you can
simply include it like this:
``` javascript
//= require refile
```
Otherwise you can grab a copy [here](https://raw.githubusercontent.com/refile/refile/master/app/assets/javascripts/refile.js).
Be sure to always update your copy of this file when you upgrade to the latest
Refile version.
Now mark the field for direct upload:
``` erb
<%= form.attachment_field :profile_image, direct: true %>
```
There is no step 3 ;)
The file is now uploaded to the `cache` immediately after the user chooses a file.
If you try this in the browser, you'll notice that an AJAX request is fired as
soon as you choose a file. Then when you submit to the server, the file is no
longer submitted, only its id.
If you want to improve the experience of this, the JavaScript library fires
a couple of custom DOM events. These events bubble, so you can also listen for
them on the form for example:
``` javascript
form.addEventListener("upload:start", function() {
// ...
});
form.addEventListener("upload:success", function() {
// ...
});
input.addEventListener("upload:progress", function() {
// ...
});
```
You can also listen for them with jQuery, even with event delegation:
``` javascript
$(document).on("upload:start", "form", function(e) {
// ...
});
```
This way you could for example disable the submit button until all files have
uploaded:
``` javascript
$(document).on("upload:start", "form", function(e) {
$(this).find("input[type=submit]").attr("disabled", true)
});
$(document).on("upload:complete", "form", function(e) {
if(!$(this).find("input.uploading").length) {
$(this).find("input[type=submit]").removeAttr("disabled")
}
});
```
### Presigned uploads
Amazon S3 supports uploads directly from the browser to S3 buckets. With this
feature you can bypass your application entirely; uploads never hit your application
at all. Unfortunately the default configuration of S3 buckets does not allow
cross site AJAX requests from posting to buckets. Fixing this is easy though.
- Open the AWS S3 console and locate your bucket
- Right click on it and choose "Properties"
- Open the "Permission" section
- Click "Add CORS Configuration"
The default configuration only allows "GET", you'll want to allow "POST" as
well. You'll also want to permit the "Content-Type" and "Origin" headers.
It could look something like this:
``` xml
<CORSConfiguration>
<CORSRule>
<AllowedOrigin>*</AllowedOrigin>
<AllowedMethod>GET</AllowedMethod>
<AllowedMethod>POST</AllowedMethod>
<MaxAgeSeconds>3000</MaxAgeSeconds>
<AllowedHeader>Authorization</AllowedHeader>
<AllowedHeader>Content-Type</AllowedHeader>
<AllowedHeader>Origin</AllowedHeader>
</CORSRule>
</CORSConfiguration>
```
If you're paranoid you can restrict the allowed origin to only your domain, but
since your bucket is only writable with authentication anyway, this shouldn't
be necessary. Note that you do not need to, and in fact you shouldn't, make
your bucket world writable.
Once you've put in the new configuration, click "Save". After that it may take
some time for the CORS setup to kick in (because of DNS propagation).
Now you can enable presigned uploads:
``` erb
<%= form.attachment_field :profile_image, presigned: true %>
```
You can also enable both direct and presigned uploads, and it'll fall back to
direct uploads if presigned uploads aren't available. This is useful if you're
using the FileSystem backend in development or test mode and the S3 backend in
production mode.
``` erb
<%= form.attachment_field :profile_image, direct: true, presigned: true %>
```
### Browser compatibility
Refile's JavaScript library requires HTML5 features which are unavailable on
IE9 and earlier versions. All other major browsers are supported.
## Authentication
URLs generated by Refile are cryptographically signed. This ensures that a file
cannot be downloaded unless you hand someone the URL to that file. This is
essentially equivalent to token base authentication.
Unfortunately a similar system is not in place for file uploads, meaning that
direct file uploads are open to anyone. By default only the `cache` backend can
be uploaded to, and you are encouraged to purge unused files from this backend
periodically. This might seem insecure, but consider the fact that anyone who
can access file uploads in your application will be able to upload files into
it anyway.
Nevertheless, you can disable direct file uploads by setting:
```
Refile.allow_uploads_to = []
```
You also have the option of explicitly authenticating anyone who tries to
access the Refile application. Since the Refile application is a Sinatra
application, you can use Sinatra's before hooks to set up authentication like
this:
```
Refile::App.before do
halt 403 unless User.find_by(id: session[:user_id])
end
```
## Additional metadata
In the quick start example above, we chose to only store the file id, but often
it is useful to store the file's filename, size and content type as well.
Refile makes it easy to extract this data and store it alongside the id. All you
need to do is add columns for these:
``` ruby
class StoreMetadata < ActiveRecord::Migration
def change
add_column :users, :profile_image_filename, :string
add_column :users, :profile_image_size, :integer
add_column :users, :profile_image_content_type, :string
end
end
```
These columns will now be filled automatically.
## File type validations
Refile can check that attached files have a given content type or extension.
This allows you to warn users if they try to upload an invalid file.
**Important:** You should regard this as a convenience feature for your users,
not a security feature. Both file extension and content type can easily be
spoofed.
In order to limit attachments to an extension or content type, you can provide
them like this:
``` ruby
attachment :cv, extension: "pdf"
attachment :profile_image, content_type: "image/jpeg"
```
You can also provide a list of content types or extensions:
``` ruby
attachment :cv, extension: ["pdf", "doc"]
attachment :profile_image, content_type: ["image/jpeg", "image/png", "image/gif"]
```
Since the combination of JPEG, PNG and GIF is so common, you can also specify
this more succinctly like this:
``` ruby
attachment :profile_image, type: :image
```
When a user uploads a file with an invalid extension or content type and
submits the form, they'll be presented with a validation error.
If you use a particular content type or set of content types frequently
you can define your own types like this:
``` ruby
Refile.types[:document] = Refile::Type.new(:document,
content_type: %w[text/plain application/pdf]
)
```
Now you can use them like this:
``` ruby
attachment :profile_image, type: :document
```
## Multiple file uploads
File input fields support the `multiple` attribute which allows users to attach
multiple files at once. Refile supports this attribute. You can add the
attribute to your attachment fields like this:
``` erb
<%= form.attachment_field :images_files, multiple: true %>
```
Multiple file uploads also work nicely with direct and presigned uploads:
``` erb
<%= form.attachment_field :images_files, multiple: true, direct: true, presigned: true %>
```
Note that you will get separate events for each uploaded file. So when you
attach two files, the `upload:start` event and other events will be triggered
twice, once for each file.
When you upload multiple files, your application will receive an array of
files, instead of a single file. To map these files to model object, Refile's
ActiveRecord integration ships with a nice macro that makes this trivial. Suppose
you have an image model like this:
``` ruby
class Image < ActiveRecord::Base
belongs_to :post
attachment :file
end
```
Note it must be possible to persist images given only the associated post and a
file. There must not be any other validations or constraints which prevent
images from being saved.
From the post model, you can use the `accepts_attachments_for` macro:
``` ruby
class Post < ActiveRecord::Base
has_many :images, dependent: :destroy, autosave: true
accepts_attachments_for :images, attachment: :file
end
```
The `attachment` option defaults to `:file`, so we could have left it out in
this case.
``` ruby
class Post < ActiveRecord::Base
has_many :images, dependent: :destroy, autosave: true
accepts_attachments_for :images
end
```
Note: Leaving out the `autosave` option will only save the attachments when the post is created.
You can add the attachment field to your post form:
``` erb
<%= form_for @post do |form| %>
<%= form.label :images_files %>
<%= form.attachment_field :images_files, multiple: true %>
<% end %>
```
Now you only need to permit the generated accessor in your controller. Since
`images_files` is an array, you need to tell Rails to allow array values for
it:
``` ruby
def post_params
params.require(:post).permit(images_files: [])
end
```
When editing a record with `accepts_attachments_for`, the default behaviour is
to replace the entire list of attachments when new attachments are uploaded. It
is also possible to append the new attachments to the list of attachments instead
so that older attachments are kept. To enable this, set the `append` option to
`true`.
``` ruby
class Post < ActiveRecord::Base
has_many :images, dependent: :destroy
accepts_attachments_for :images, append: true
end
```
### Multiple file uploads for pure Ruby classes
You can also use `accepts_attachments_for` macro in pure Ruby classes.
Suppose you have a `Document` class to be associated with a `Post` class.
A post has many documents, and each document has a file.
First, you will need to use the `attachment` macro in the `Document` class to
declare your `:file` attachment, and also implement a constructor to receive
the attachment:
```ruby
class Document
extend Refile::Attachment
attr_accessor :file_id
attachment :file
def initialize(attributes = {})
self.file = attributes[:file]
end
end
```
In the `Post` class, you will need a constructor to initialize the `@documents`
variable and an `attr_accessor :documents`. Then you can use the `accepts_attachments_for`
macro for declaring the `:documents` collection:
```ruby
class Post
extend Refile::Attachment
include ActiveModel::Model
attr_accessor :documents
accepts_attachments_for(
:documents,
accessor_prefix: 'documents_files',
collection_class: Document
)
def initialize(attributes = {})
@documents = attributes[:documents] || []
end
end
```
In this example, we specified the following options:
- `collection_class` is the attachments class, `Document`
- `accessor_prefix` gives a prefix to the generated accessors, `documents_files`.
Now you can append attachments with your HTML form in the following way:
```erb
<%= form_for @post do |form| %>
<%= form.label :documents_files %>
<%= form.attachment_field :documents_files, multiple: true %>
<% end %>
```
The default values for the `accepts_attachments_for` macro are
`{ attachment: :file, append: false }`. Everything else should be similar to
the Active Record version of this macro.
## Single file upload
File input fields support single file upload, allows users to attach
one file at the time instead of the common multiple files feature.
Let's suppose you have an image model like this:
``` ruby
class Image < ActiveRecord::Base
belongs_to :post
attachment :file
end
```
Note it must be possible to persist images given only the associated post and a
file. There must not be any other validations or constraints which prevent
images from being saved.
From the post model, you can use the `accepts_attachments_for` macro:
``` ruby
class Post < ActiveRecord::Base
has_many :images, dependent: :destroy
accepts_attachments_for :images, attachment: :file
end
```
The `attachment` option defaults to `:file`, so we could have left it out in
this case.
``` ruby
class Post < ActiveRecord::Base
has_many :images, dependent: :destroy
accepts_attachments_for :images
end
```
You can add the attachment field to your post form without using the `multiple`
attribute:
``` erb
<%= form_for @post do |form| %>
<%= form.label :images_files %>
<%= form.attachment_field :images_files %>
<% end %>
```
Now you only need to permit the generated accessor in your controller. Since
`images_files` is not an array, you need to tell Rails to only allow the
attribute symbol:
``` ruby
def post_params
params.require(:post).permit(:images_files)
end
```
## Removing attached files
File input fields unfortunately do not have the option of removing an already
uploaded file. This is problematic when editing a model which has a file attached
and the user wants to remove this file. To work around this, Refile automatically
adds an attribute to your model when you use the `attachment` method, which is
designed to be used with a checkbox in a form.
``` erb
<%= form_for @user do |form| %>
<%= form.label :profile_image %>
<%= form.attachment_field :profile_image %>
<%= form.check_box :remove_profile_image %>
<%= form.label :remove_profile_image %>
<% end %>
```
Don't forget to permit this attribute in your controller:
``` ruby
def user_params
params.require(:user).permit(:profile_image, :remove_profile_image)
end
```
Now when you check this checkbox and submit the form, the previously attached
file will be removed.
## Fetching remote files by URL
You might want to give you users the option of uploading a file by its URL.
This could be either just via a textfield or through some other interface.
Refile makes it easy to fetch this file and upload it. Just add a field like
this:
``` erb
<%= form_for @user do |form| %>
<%= form.label :profile_image, "Attach image" %>
<%= form.attachment_field :profile_image %>
<%= form.label :remote_profile_image_url, "Or specify URL" %>
<%= form.text_field :remote_profile_image_url %>
<% end %>
```
Then permit this field in your controller:
``` ruby
def user_params
params.require(:user).permit(:profile_image, :remote_profile_image_url)
end
```
Refile will now fetch the file from the given URL, following redirects if
needed.
## Cache expiry
Files will accumulate in your cache, and you'll probably want to remove them
after some time.
The FileSystem backend does not currently provide any method of doing this. PRs
welcome ;)
On S3 this can be conveniently handled through lifecycle rules. Exactly how
depends a bit on your setup. If you are using the suggested setup of having
one bucket with `cache` and `store` being directories in that bucket (or prefixes
in S3 parlance), then follow the following steps, otherwise adapt them to your
needs:
- Open the AWS S3 console and locate your bucket
- Right click on it and choose "Properties"
- Open the "Lifecycle" section
- Click "Add rule"
- Choose "Apply the rule to: A prefix"
- Enter "cache/" as the prefix (trailing slash!)
- Click "Configure rule"
- For "Action on Objects" you'll probably want to choose "Permanently Delete Only"
- Choose whatever number of days you're comfortable with, I chose "1"
- Click "Review" and finally "Create and activate Rule"
## Testing
When testing your own classes that use Refile, you can use `Refile::FileDouble` objects instead of real files.
```ruby
# app/models/post.rb
class Post < ActiveRecord::Base
attachment :image, type: :image
end
# spec/models/post_spec.rb
require "rails_helper"
require "refile/file_double"
RSpec.describe Post, type: :model do
it "allows attaching an image" do
post = Post.new
post.image = Refile::FileDouble.new("dummy", "logo.png", content_type: "image/png")
post.save
expect(post.image_id).not_to be_nil
end
it "doesn't allow attaching other files" do
post = Post.new
post.image = Refile::FileDouble.new("dummy", "file.txt", content_type: "text/plain")
post.save
expect(post.image_id).to be_nil
end
end
```
## simple_form
simple_form gem is also supported:
```Ruby
# in initializer or Gemfile
require 'refile/simple_form'
# in forms
<%= f.input :cover_image, as: :attachment, direct: true, presigned: true %>
```
## License
[MIT](LICENSE.txt)