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<h2>Active Storage Overview</h2><p>This guide covers how to attach files to your Active Record models.</p><p>After reading this guide, you will know:</p>
<ul>
<li>How to attach one or many files to a record.</li>
<li>How to delete an attached file.</li>
<li>How to link to an attached file.</li>
<li>How to use variants to transform images.</li>
<li>How to generate an image representation of a non-image file, such as a PDF or a video.</li>
<li>How to send file uploads directly from browsers to a storage service,
bypassing your application servers.</li>
<li>How to clean up files stored during testing.</li>
<li>How to implement support for additional storage services.</li>
</ul>
<div id="subCol">
<h3 class="chapter"><img src="images/chapters_icon.gif" alt="" />Chapters</h3>
<ol class="chapters">
<li><a href="#what-is-active-storage-questionmark">What is Active Storage?</a></li>
<li>
<a href="#setup">Setup</a>
<ul>
<li><a href="#disk-service">Disk Service</a></li>
<li><a href="#amazon-s3-service">Amazon S3 Service</a></li>
<li><a href="#microsoft-azure-storage-service">Microsoft Azure Storage Service</a></li>
<li><a href="#google-cloud-storage-service">Google Cloud Storage Service</a></li>
<li><a href="#mirror-service">Mirror Service</a></li>
</ul>
</li>
<li>
<a href="#attaching-files-to-records">Attaching Files to Records</a>
<ul>
<li><a href="#has-one-attached"><code>has_one_attached</code></a></li>
<li><a href="#has-many-attached"><code>has_many_attached</code></a></li>
<li><a href="#attaching-file-io-objects">Attaching File/IO Objects</a></li>
</ul>
</li>
<li><a href="#removing-files">Removing Files</a></li>
<li><a href="#linking-to-files">Linking to Files</a></li>
<li><a href="#downloading-files">Downloading Files</a></li>
<li><a href="#transforming-images">Transforming Images</a></li>
<li><a href="#previewing-files">Previewing Files</a></li>
<li>
<a href="#direct-uploads">Direct Uploads</a>
<ul>
<li><a href="#direct-upload-installation">Direct upload installation</a></li>
<li><a href="#direct-upload-javascript-events">Direct upload JavaScript events</a></li>
<li><a href="#example">Example</a></li>
<li><a href="#integrating-with-libraries-or-frameworks">Integrating with Libraries or Frameworks</a></li>
</ul>
</li>
<li><a href="#discarding-files-stored-during-system-tests">Discarding Files Stored During System Tests</a></li>
<li><a href="#discarding-files-stored-during-integration-tests">Discarding Files Stored During Integration Tests</a></li>
<li><a href="#implementing-support-for-other-cloud-services">Implementing Support for Other Cloud Services</a></li>
</ol>
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<div id="mainCol">
<h3 id="what-is-active-storage-questionmark"><a class="anchorlink" href="#what-is-active-storage-questionmark">1 What is Active Storage?</a></h3><p>Active Storage facilitates uploading files to a cloud storage service like
Amazon S3, Google Cloud Storage, or Microsoft Azure Storage and attaching those
files to Active Record objects. It comes with a local disk-based service for
development and testing and supports mirroring files to subordinate services for
backups and migrations.</p><p>Using Active Storage, an application can transform image uploads with
<a href="https://www.imagemagick.org">ImageMagick</a>, generate image representations of
non-image uploads like PDFs and videos, and extract metadata from arbitrary
files.</p><h3 id="setup"><a class="anchorlink" href="#setup">2 Setup</a></h3><p>Active Storage uses two tables in your application’s database named
<code>active_storage_blobs</code> and <code>active_storage_attachments</code>. After creating a new
application (or upgrading your application to Rails 5.2), run
<code>rails active_storage:install</code> to generate a migration that creates these
tables. Use <code>rails db:migrate</code> to run the migration.</p><p>Declare Active Storage services in <code>config/storage.yml</code>. For each service your
application uses, provide a name and the requisite configuration. The example
below declares three services named <code>local</code>, <code>test</code>, and <code>amazon</code>:</p><div class="code_container">
<pre class="brush: plain; gutter: false; toolbar: false">
local:
service: Disk
root: <%= Rails.root.join("storage") %>
test:
service: Disk
root: <%= Rails.root.join("tmp/storage") %>
amazon:
service: S3
access_key_id: ""
secret_access_key: ""
bucket: ""
region: "" # e.g. 'us-east-1'
</pre>
</div>
<p>Tell Active Storage which service to use by setting
<code>Rails.application.config.active_storage.service</code>. Because each environment will
likely use a different service, it is recommended to do this on a
per-environment basis. To use the disk service from the previous example in the
development environment, you would add the following to
<code>config/environments/development.rb</code>:</p><div class="code_container">
<pre class="brush: ruby; gutter: false; toolbar: false">
# Store files locally.
config.active_storage.service = :local
</pre>
</div>
<p>To use the Amazon S3 service in production, you add the following to
<code>config/environments/production.rb</code>:</p><div class="code_container">
<pre class="brush: ruby; gutter: false; toolbar: false">
# Store files on Amazon S3.
config.active_storage.service = :amazon
</pre>
</div>
<p>To use the test service when testing, you add the following to
<code>config/environments/test.rb</code>:</p><div class="code_container">
<pre class="brush: ruby; gutter: false; toolbar: false">
# Store uploaded files on the local file system in a temporary directory.
config.active_storage.service = :test
</pre>
</div>
<p>Continue reading for more information on the built-in service adapters (e.g.
<code>Disk</code> and <code>S3</code>) and the configuration they require.</p><h4 id="disk-service"><a class="anchorlink" href="#disk-service">2.1 Disk Service</a></h4><p>Declare a Disk service in <code>config/storage.yml</code>:</p><div class="code_container">
<pre class="brush: plain; gutter: false; toolbar: false">
local:
service: Disk
root: <%= Rails.root.join("storage") %>
</pre>
</div>
<h4 id="amazon-s3-service"><a class="anchorlink" href="#amazon-s3-service">2.2 Amazon S3 Service</a></h4><p>Declare an S3 service in <code>config/storage.yml</code>:</p><div class="code_container">
<pre class="brush: plain; gutter: false; toolbar: false">
amazon:
service: S3
access_key_id: ""
secret_access_key: ""
region: ""
bucket: ""
</pre>
</div>
<p>Add the <a href="https://github.com/aws/aws-sdk-ruby"><code>aws-sdk-s3</code></a> gem to your <code>Gemfile</code>:</p><div class="code_container">
<pre class="brush: ruby; gutter: false; toolbar: false">
gem "aws-sdk-s3", require: false
</pre>
</div>
<div class="note"><p>The core features of Active Storage require the following permissions: <code>s3:ListBucket</code>, <code>s3:PutObject</code>, <code>s3:GetObject</code>, and <code>s3:DeleteObject</code>. If you have additional upload options configured such as setting ACLs then additional permissions may be required.</p></div><div class="note"><p>If you want to use environment variables, standard SDK configuration files, profiles,
IAM instance profiles or task roles, you can omit the <code>access_key_id</code>, <code>secret_access_key</code>,
and <code>region</code> keys in the example above. The Amazon S3 Service supports all of the
authentication options described in the <a href="https://docs.aws.amazon.com/sdk-for-ruby/v3/developer-guide/setup-config.html">AWS SDK documentation</a>.</p></div><h4 id="microsoft-azure-storage-service"><a class="anchorlink" href="#microsoft-azure-storage-service">2.3 Microsoft Azure Storage Service</a></h4><p>Declare an Azure Storage service in <code>config/storage.yml</code>:</p><div class="code_container">
<pre class="brush: plain; gutter: false; toolbar: false">
azure:
service: AzureStorage
storage_account_name: ""
storage_access_key: ""
container: ""
</pre>
</div>
<p>Add the <a href="https://github.com/Azure/azure-storage-ruby"><code>azure-storage</code></a> gem to your <code>Gemfile</code>:</p><div class="code_container">
<pre class="brush: ruby; gutter: false; toolbar: false">
gem "azure-storage", require: false
</pre>
</div>
<h4 id="google-cloud-storage-service"><a class="anchorlink" href="#google-cloud-storage-service">2.4 Google Cloud Storage Service</a></h4><p>Declare a Google Cloud Storage service in <code>config/storage.yml</code>:</p><div class="code_container">
<pre class="brush: plain; gutter: false; toolbar: false">
google:
service: GCS
credentials: <%= Rails.root.join("path/to/keyfile.json") %>
project: ""
bucket: ""
</pre>
</div>
<p>Optionally provide a Hash of credentials instead of a keyfile path:</p><div class="code_container">
<pre class="brush: plain; gutter: false; toolbar: false">
google:
service: GCS
credentials:
type: "service_account"
project_id: ""
private_key_id: <%= Rails.application.credentials.dig(:gcs, :private_key_id) %>
private_key: <%= Rails.application.credentials.dig(:gcs, :private_key).dump %>
client_email: ""
client_id: ""
auth_uri: "https://accounts.google.com/o/oauth2/auth"
token_uri: "https://accounts.google.com/o/oauth2/token"
auth_provider_x509_cert_url: "https://www.googleapis.com/oauth2/v1/certs"
client_x509_cert_url: ""
project: ""
bucket: ""
</pre>
</div>
<p>Add the <a href="https://github.com/GoogleCloudPlatform/google-cloud-ruby/tree/master/google-cloud-storage"><code>google-cloud-storage</code></a> gem to your <code>Gemfile</code>:</p><div class="code_container">
<pre class="brush: ruby; gutter: false; toolbar: false">
gem "google-cloud-storage", "~> 1.11", require: false
</pre>
</div>
<h4 id="mirror-service"><a class="anchorlink" href="#mirror-service">2.5 Mirror Service</a></h4><p>You can keep multiple services in sync by defining a mirror service. When a file
is uploaded or deleted, it's done across all the mirrored services. Mirrored
services can be used to facilitate a migration between services in production.
You can start mirroring to the new service, copy existing files from the old
service to the new, then go all-in on the new service. Define each of the
services you'd like to use as described above and reference them from a mirrored
service.</p><div class="code_container">
<pre class="brush: plain; gutter: false; toolbar: false">
s3_west_coast:
service: S3
access_key_id: ""
secret_access_key: ""
region: ""
bucket: ""
s3_east_coast:
service: S3
access_key_id: ""
secret_access_key: ""
region: ""
bucket: ""
production:
service: Mirror
primary: s3_east_coast
mirrors:
- s3_west_coast
</pre>
</div>
<div class="note"><p>Files are served from the primary service.</p></div><div class="note"><p>This is not compatible with the <a href="#direct-uploads">direct uploads</a> feature.</p></div><h3 id="attaching-files-to-records"><a class="anchorlink" href="#attaching-files-to-records">3 Attaching Files to Records</a></h3><h4 id="has-one-attached"><a class="anchorlink" href="#has-one-attached">3.1 <code>has_one_attached</code></a></h4><p>The <code>has_one_attached</code> macro sets up a one-to-one mapping between records and
files. Each record can have one file attached to it.</p><p>For example, suppose your application has a <code>User</code> model. If you want each user to
have an avatar, define the <code>User</code> model like this:</p><div class="code_container">
<pre class="brush: ruby; gutter: false; toolbar: false">
class User < ApplicationRecord
has_one_attached :avatar
end
</pre>
</div>
<p>You can create a user with an avatar:</p><div class="code_container">
<pre class="brush: ruby; html-script: true; gutter: false; toolbar: false">
<%= form.file_field :avatar %>
</pre>
</div>
<div class="code_container">
<pre class="brush: ruby; gutter: false; toolbar: false">
class SignupController < ApplicationController
def create
user = User.create!(user_params)
session[:user_id] = user.id
redirect_to root_path
end
private
def user_params
params.require(:user).permit(:email_address, :password, :avatar)
end
end
</pre>
</div>
<p>Call <code>avatar.attach</code> to attach an avatar to an existing user:</p><div class="code_container">
<pre class="brush: ruby; gutter: false; toolbar: false">
user.avatar.attach(params[:avatar])
</pre>
</div>
<p>Call <code>avatar.attached?</code> to determine whether a particular user has an avatar:</p><div class="code_container">
<pre class="brush: ruby; gutter: false; toolbar: false">
user.avatar.attached?
</pre>
</div>
<h4 id="has-many-attached"><a class="anchorlink" href="#has-many-attached">3.2 <code>has_many_attached</code></a></h4><p>The <code>has_many_attached</code> macro sets up a one-to-many relationship between records
and files. Each record can have many files attached to it.</p><p>For example, suppose your application has a <code>Message</code> model. If you want each
message to have many images, define the <code>Message</code> model like this:</p><div class="code_container">
<pre class="brush: ruby; gutter: false; toolbar: false">
class Message < ApplicationRecord
has_many_attached :images
end
</pre>
</div>
<p>You can create a message with images:</p><div class="code_container">
<pre class="brush: ruby; gutter: false; toolbar: false">
class MessagesController < ApplicationController
def create
message = Message.create!(message_params)
redirect_to message
end
private
def message_params
params.require(:message).permit(:title, :content, images: [])
end
end
</pre>
</div>
<p>Call <code>images.attach</code> to add new images to an existing message:</p><div class="code_container">
<pre class="brush: ruby; gutter: false; toolbar: false">
@message.images.attach(params[:images])
</pre>
</div>
<p>Call <code>images.attached?</code> to determine whether a particular message has any images:</p><div class="code_container">
<pre class="brush: ruby; gutter: false; toolbar: false">
@message.images.attached?
</pre>
</div>
<h4 id="attaching-file-io-objects"><a class="anchorlink" href="#attaching-file-io-objects">3.3 Attaching File/IO Objects</a></h4><p>Sometimes you need to attach a file that doesn’t arrive via an HTTP request.
For example, you may want to attach a file you generated on disk or downloaded
from a user-submitted URL. You may also want to attach a fixture file in a
model test. To do that, provide a Hash containing at least an open IO object
and a filename:</p><div class="code_container">
<pre class="brush: ruby; gutter: false; toolbar: false">
@message.image.attach(io: File.open('/path/to/file'), filename: 'file.pdf')
</pre>
</div>
<p>When possible, provide a content type as well. Active Storage attempts to
determine a file’s content type from its data. It falls back to the content
type you provide if it can’t do that.</p><div class="code_container">
<pre class="brush: ruby; gutter: false; toolbar: false">
@message.image.attach(io: File.open('/path/to/file'), filename: 'file.pdf', content_type: 'application/pdf')
</pre>
</div>
<p>You can bypass the content type inference from the data by passing in
<code>identify: false</code> along with the <code>content_type</code>.</p><div class="code_container">
<pre class="brush: ruby; gutter: false; toolbar: false">
@message.image.attach(
io: File.open('/path/to/file'),
filename: 'file.pdf',
content_type: 'application/pdf',
identify: false
)
</pre>
</div>
<p>If you don’t provide a content type and Active Storage can’t determine the
file’s content type automatically, it defaults to application/octet-stream.</p><h3 id="removing-files"><a class="anchorlink" href="#removing-files">4 Removing Files</a></h3><p>To remove an attachment from a model, call <code>purge</code> on the attachment. Removal
can be done in the background if your application is setup to use Active Job.
Purging deletes the blob and the file from the storage service.</p><div class="code_container">
<pre class="brush: ruby; gutter: false; toolbar: false">
# Synchronously destroy the avatar and actual resource files.
user.avatar.purge
# Destroy the associated models and actual resource files async, via Active Job.
user.avatar.purge_later
</pre>
</div>
<h3 id="linking-to-files"><a class="anchorlink" href="#linking-to-files">5 Linking to Files</a></h3><p>Generate a permanent URL for the blob that points to the application. Upon
access, a redirect to the actual service endpoint is returned. This indirection
decouples the public URL from the actual one, and allows, for example, mirroring
attachments in different services for high-availability. The redirection has an
HTTP expiration of 5 min.</p><div class="code_container">
<pre class="brush: ruby; gutter: false; toolbar: false">
url_for(user.avatar)
</pre>
</div>
<p>To create a download link, use the <code>rails_blob_{path|url}</code> helper. Using this
helper allows you to set the disposition.</p><div class="code_container">
<pre class="brush: ruby; gutter: false; toolbar: false">
rails_blob_path(user.avatar, disposition: "attachment")
</pre>
</div>
<p>If you need to create a link from outside of controller/view context (Background
jobs, Cronjobs, etc.), you can access the rails_blob_path like this:</p><div class="code_container">
<pre class="brush: plain; gutter: false; toolbar: false">
Rails.application.routes.url_helpers.rails_blob_path(user.avatar, only_path: true)
</pre>
</div>
<h3 id="downloading-files"><a class="anchorlink" href="#downloading-files">6 Downloading Files</a></h3><p>Sometimes you need to process a blob after it’s uploaded—for example, to convert
it to a different format. Use <code>ActiveStorage::Blob#download</code> to read a blob’s
binary data into memory:</p><div class="code_container">
<pre class="brush: ruby; gutter: false; toolbar: false">
binary = user.avatar.download
</pre>
</div>
<p>You might want to download a blob to a file on disk so an external program (e.g.
a virus scanner or media transcoder) can operate on it. Use
<code>ActiveStorage::Blob#open</code> to download a blob to a tempfile on disk:</p><div class="code_container">
<pre class="brush: ruby; gutter: false; toolbar: false">
message.video.open do |file|
system '/path/to/virus/scanner', file.path
# ...
end
</pre>
</div>
<h3 id="transforming-images"><a class="anchorlink" href="#transforming-images">7 Transforming Images</a></h3><p>To create a variation of the image, call <code>variant</code> on the <code>Blob</code>. You can pass
any transformation to the method supported by the processor. The default
processor is <a href="https://github.com/minimagick/minimagick">MiniMagick</a>, but you
can also use <a href="http://www.rubydoc.info/gems/ruby-vips/Vips/Image">Vips</a>.</p><p>To enable variants, add the <code>image_processing</code> gem to your <code>Gemfile</code>:</p><div class="code_container">
<pre class="brush: ruby; gutter: false; toolbar: false">
gem 'image_processing', '~> 1.2'
</pre>
</div>
<p>When the browser hits the variant URL, Active Storage will lazily transform the
original blob into the specified format and redirect to its new service
location.</p><div class="code_container">
<pre class="brush: ruby; html-script: true; gutter: false; toolbar: false">
<%= image_tag user.avatar.variant(resize_to_fit: [100, 100]) %>
</pre>
</div>
<p>To switch to the Vips processor, you would add the following to
<code>config/application.rb</code>:</p><div class="code_container">
<pre class="brush: ruby; gutter: false; toolbar: false">
# Use Vips for processing variants.
config.active_storage.variant_processor = :vips
</pre>
</div>
<h3 id="previewing-files"><a class="anchorlink" href="#previewing-files">8 Previewing Files</a></h3><p>Some non-image files can be previewed: that is, they can be presented as images.
For example, a video file can be previewed by extracting its first frame. Out of
the box, Active Storage supports previewing videos and PDF documents.</p><div class="code_container">
<pre class="brush: ruby; html-script: true; gutter: false; toolbar: false">
<ul>
<% @message.files.each do |file| %>
<li>
<%= image_tag file.preview(resize_to_limit: [100, 100]) %>
</li>
<% end %>
</ul>
</pre>
</div>
<div class="warning"><p>Extracting previews requires third-party applications, FFmpeg for
video and muPDF for PDFs, and on macOS also XQuartz and Poppler.
These libraries are not provided by Rails. You must install them yourself to
use the built-in previewers. Before you install and use third-party software,
make sure you understand the licensing implications of doing so.</p></div><h3 id="direct-uploads"><a class="anchorlink" href="#direct-uploads">9 Direct Uploads</a></h3><p>Active Storage, with its included JavaScript library, supports uploading
directly from the client to the cloud.</p><h4 id="direct-upload-installation"><a class="anchorlink" href="#direct-upload-installation">9.1 Direct upload installation</a></h4>
<ol>
<li>
<p>Include <code>activestorage.js</code> in your application's JavaScript bundle.</p>
<p>Using the asset pipeline:</p>
<div class="code_container">
<pre class="brush: plain; gutter: false; toolbar: false">
//= require activestorage
</pre>
</div>
<p>Using the npm package:</p>
<div class="code_container">
<pre class="brush: plain; gutter: false; toolbar: false">
import * as ActiveStorage from "activestorage"
ActiveStorage.start()
</pre>
</div>
</li>
<li>
<p>Annotate file inputs with the direct upload URL.</p>
<div class="code_container">
<pre class="brush: ruby; html-script: true; gutter: false; toolbar: false">
<%= form.file_field :attachments, multiple: true, direct_upload: true %>
</pre>
</div>
</li>
<li><p>That's it! Uploads begin upon form submission.</p></li>
</ol>
<h4 id="direct-upload-javascript-events"><a class="anchorlink" href="#direct-upload-javascript-events">9.2 Direct upload JavaScript events</a></h4>
<table>
<thead>
<tr>
<th>Event name</th>
<th>Event target</th>
<th>Event data (<code>event.detail</code>)</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr>
<td><code>direct-uploads:start</code></td>
<td><code><form></code></td>
<td>None</td>
<td>A form containing files for direct upload fields was submitted.</td>
</tr>
<tr>
<td><code>direct-upload:initialize</code></td>
<td><code><input></code></td>
<td><code>{id, file}</code></td>
<td>Dispatched for every file after form submission.</td>
</tr>
<tr>
<td><code>direct-upload:start</code></td>
<td><code><input></code></td>
<td><code>{id, file}</code></td>
<td>A direct upload is starting.</td>
</tr>
<tr>
<td><code>direct-upload:before-blob-request</code></td>
<td><code><input></code></td>
<td><code>{id, file, xhr}</code></td>
<td>Before making a request to your application for direct upload metadata.</td>
</tr>
<tr>
<td><code>direct-upload:before-storage-request</code></td>
<td><code><input></code></td>
<td><code>{id, file, xhr}</code></td>
<td>Before making a request to store a file.</td>
</tr>
<tr>
<td><code>direct-upload:progress</code></td>
<td><code><input></code></td>
<td><code>{id, file, progress}</code></td>
<td>As requests to store files progress.</td>
</tr>
<tr>
<td><code>direct-upload:error</code></td>
<td><code><input></code></td>
<td><code>{id, file, error}</code></td>
<td>An error occurred. An <code>alert</code> will display unless this event is canceled.</td>
</tr>
<tr>
<td><code>direct-upload:end</code></td>
<td><code><input></code></td>
<td><code>{id, file}</code></td>
<td>A direct upload has ended.</td>
</tr>
<tr>
<td><code>direct-uploads:end</code></td>
<td><code><form></code></td>
<td>None</td>
<td>All direct uploads have ended.</td>
</tr>
</tbody>
</table>
<h4 id="example"><a class="anchorlink" href="#example">9.3 Example</a></h4><p>You can use these events to show the progress of an upload.</p><p><img src="https://user-images.githubusercontent.com/5355/28694528-16e69d0c-72f8-11e7-91a7-c0b8cfc90391.gif" alt="direct-uploads"></p><p>To show the uploaded files in a form:</p><div class="code_container">
<pre class="brush: plain; gutter: false; toolbar: false">
// direct_uploads.js
addEventListener("direct-upload:initialize", event => {
const { target, detail } = event
const { id, file } = detail
target.insertAdjacentHTML("beforebegin", `
<div id="direct-upload-${id}" class="direct-upload direct-upload--pending">
<div id="direct-upload-progress-${id}" class="direct-upload__progress" style="width: 0%"></div>
<span class="direct-upload__filename">${file.name}</span>
</div>
`)
})
addEventListener("direct-upload:start", event => {
const { id } = event.detail
const element = document.getElementById(`direct-upload-${id}`)
element.classList.remove("direct-upload--pending")
})
addEventListener("direct-upload:progress", event => {
const { id, progress } = event.detail
const progressElement = document.getElementById(`direct-upload-progress-${id}`)
progressElement.style.width = `${progress}%`
})
addEventListener("direct-upload:error", event => {
event.preventDefault()
const { id, error } = event.detail
const element = document.getElementById(`direct-upload-${id}`)
element.classList.add("direct-upload--error")
element.setAttribute("title", error)
})
addEventListener("direct-upload:end", event => {
const { id } = event.detail
const element = document.getElementById(`direct-upload-${id}`)
element.classList.add("direct-upload--complete")
})
</pre>
</div>
<p>Add styles:</p><div class="code_container">
<pre class="brush: plain; gutter: false; toolbar: false">
/* direct_uploads.css */
.direct-upload {
display: inline-block;
position: relative;
padding: 2px 4px;
margin: 0 3px 3px 0;
border: 1px solid rgba(0, 0, 0, 0.3);
border-radius: 3px;
font-size: 11px;
line-height: 13px;
}
.direct-upload--pending {
opacity: 0.6;
}
.direct-upload__progress {
position: absolute;
top: 0;
left: 0;
bottom: 0;
opacity: 0.2;
background: #0076ff;
transition: width 120ms ease-out, opacity 60ms 60ms ease-in;
transform: translate3d(0, 0, 0);
}
.direct-upload--complete .direct-upload__progress {
opacity: 0.4;
}
.direct-upload--error {
border-color: red;
}
input[type=file][data-direct-upload-url][disabled] {
display: none;
}
</pre>
</div>
<h4 id="integrating-with-libraries-or-frameworks"><a class="anchorlink" href="#integrating-with-libraries-or-frameworks">9.4 Integrating with Libraries or Frameworks</a></h4><p>If you want to use the Direct Upload feature from a JavaScript framework, or
you want to integrate custom drag and drop solutions, you can use the
<code>DirectUpload</code> class for this purpose. Upon receiving a file from your library
of choice, instantiate a DirectUpload and call its create method. Create takes
a callback to invoke when the upload completes.</p><div class="code_container">
<pre class="brush: plain; gutter: false; toolbar: false">
import { DirectUpload } from "activestorage"
const input = document.querySelector('input[type=file]')
// Bind to file drop - use the ondrop on a parent element or use a
// library like Dropzone
const onDrop = (event) => {
event.preventDefault()
const files = event.dataTransfer.files;
Array.from(files).forEach(file => uploadFile(file))
}
// Bind to normal file selection
input.addEventListener('change', (event) => {
Array.from(input.files).forEach(file => uploadFile(file))
// you might clear the selected files from the input
input.value = null
})
const uploadFile = (file) => {
// your form needs the file_field direct_upload: true, which
// provides data-direct-upload-url
const url = input.dataset.directUploadUrl
const upload = new DirectUpload(file, url)
upload.create((error, blob) => {
if (error) {
// Handle the error
} else {
// Add an appropriately-named hidden input to the form with a
// value of blob.signed_id so that the blob ids will be
// transmitted in the normal upload flow
const hiddenField = document.createElement('input')
hiddenField.setAttribute("type", "hidden");
hiddenField.setAttribute("value", blob.signed_id);
hiddenField.name = input.name
document.querySelector('form').appendChild(hiddenField)
}
})
}
</pre>
</div>
<p>If you need to track the progress of the file upload, you can pass a third
parameter to the <code>DirectUpload</code> constructor. During the upload, DirectUpload
will call the object's <code>directUploadWillStoreFileWithXHR</code> method. You can then
bind your own progress handler on the XHR.</p><div class="code_container">
<pre class="brush: plain; gutter: false; toolbar: false">
import { DirectUpload } from "activestorage"
class Uploader {
constructor(file, url) {
this.upload = new DirectUpload(this.file, this.url, this)
}
upload(file) {
this.upload.create((error, blob) => {
if (error) {
// Handle the error
} else {
// Add an appropriately-named hidden input to the form
// with a value of blob.signed_id
}
})
}
directUploadWillStoreFileWithXHR(request) {
request.upload.addEventListener("progress",
event => this.directUploadDidProgress(event))
}
directUploadDidProgress(event) {
// Use event.loaded and event.total to update the progress bar
}
}
</pre>
</div>
<h3 id="discarding-files-stored-during-system-tests"><a class="anchorlink" href="#discarding-files-stored-during-system-tests">10 Discarding Files Stored During System Tests</a></h3><p>System tests clean up test data by rolling back a transaction. Because destroy
is never called on an object, the attached files are never cleaned up. If you
want to clear the files, you can do it in an <code>after_teardown</code> callback. Doing it
here ensures that all connections created during the test are complete and
you won't receive an error from Active Storage saying it can't find a file.</p><div class="code_container">
<pre class="brush: ruby; gutter: false; toolbar: false">
class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
driven_by :selenium, using: :chrome, screen_size: [1400, 1400]
def remove_uploaded_files
FileUtils.rm_rf("#{Rails.root}/storage_test")
end
def after_teardown
super
remove_uploaded_files
end
end
</pre>
</div>
<p>If your system tests verify the deletion of a model with attachments and you're
using Active Job, set your test environment to use the inline queue adapter so
the purge job is executed immediately rather at an unknown time in the future.</p><p>You may also want to use a separate service definition for the test environment
so your tests don't delete the files you create during development.</p><div class="code_container">
<pre class="brush: ruby; gutter: false; toolbar: false">
# Use inline job processing to make things happen immediately
config.active_job.queue_adapter = :inline
# Separate file storage in the test environment
config.active_storage.service = :local_test
</pre>
</div>
<h3 id="discarding-files-stored-during-integration-tests"><a class="anchorlink" href="#discarding-files-stored-during-integration-tests">11 Discarding Files Stored During Integration Tests</a></h3><p>Similarly to System Tests, files uploaded during Integration Tests will not be
automatically cleaned up. If you want to clear the files, you can do it in an
<code>after_teardown</code> callback. Doing it here ensures that all connections created
during the test are complete and you won't receive an error from Active Storage
saying it can't find a file.</p><div class="code_container">
<pre class="brush: ruby; gutter: false; toolbar: false">
module RemoveUploadedFiles
def after_teardown
super
remove_uploaded_files
end
private
def remove_uploaded_files
FileUtils.rm_rf(Rails.root.join('tmp', 'storage'))
end
end
module ActionDispatch
class IntegrationTest
prepend RemoveUploadedFiles
end
end
</pre>
</div>
<h3 id="implementing-support-for-other-cloud-services"><a class="anchorlink" href="#implementing-support-for-other-cloud-services">12 Implementing Support for Other Cloud Services</a></h3><p>If you need to support a cloud service other than these, you will need to
implement the Service. Each service extends
<a href="https://github.com/rails/rails/blob/master/activestorage/lib/active_storage/service.rb"><code>ActiveStorage::Service</code></a>
by implementing the methods necessary to upload and download files to the cloud.</p>
<h3>Feedback</h3>
<p>
You're encouraged to help improve the quality of this guide.
</p>
<p>
Please contribute if you see any typos or factual errors.
To get started, you can read our <a href="https://edgeguides.rubyonrails.org/contributing_to_ruby_on_rails.html#contributing-to-the-rails-documentation">documentation contributions</a> section.
</p>
<p>
You may also find incomplete content or stuff that is not up to date.
Please do add any missing documentation for master. Make sure to check
<a href="https://edgeguides.rubyonrails.org">Edge Guides</a> first to verify
if the issues are already fixed or not on the master branch.
Check the <a href="ruby_on_rails_guides_guidelines.html">Ruby on Rails Guides Guidelines</a>
for style and conventions.
</p>
<p>
If for whatever reason you spot something to fix but cannot patch it yourself, please
<a href="https://github.com/rails/rails/issues">open an issue</a>.
</p>
<p>And last but not least, any kind of discussion regarding Ruby on Rails
documentation is very welcome on the <a href="https://groups.google.com/forum/#!forum/rubyonrails-docs">rubyonrails-docs mailing list</a>.
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