From f4c51e8660bf1771268d45325fff8378eb90698e Mon Sep 17 00:00:00 2001
From: Steve Polito Design <stevepolitodesign@users.noreply.github.com>
Date: Thu, 14 Jan 2021 09:51:37 -0500
Subject: [PATCH] Add section on how to purge unattached uploads.

---
 guides/source/active_storage_overview.md | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/guides/source/active_storage_overview.md b/guides/source/active_storage_overview.md
index 116b45ba29..1e0dccb542 100644
--- a/guides/source/active_storage_overview.md
+++ b/guides/source/active_storage_overview.md
@@ -959,6 +959,8 @@ class Uploader {
 }
 ```
 
+NOTE: Using [Direct Uploads](#direct-uploads) can sometimes result in a file that uploads, but never attaches to a record. Consider [purging unattached uploads](#purging-unattached-uploads).
+
 Discarding Files Stored During System Tests
 -------------------------------------------
 
@@ -1035,3 +1037,19 @@ If you need to support a cloud service other than these, you will need to
 implement the Service. Each service extends
 [`ActiveStorage::Service`](https://github.com/rails/rails/blob/main/activestorage/lib/active_storage/service.rb)
 by implementing the methods necessary to upload and download files to the cloud.
+
+Purging Unattached Uploads
+--------------------------
+
+There are cases where a file is uploaded but never attached to a record. This can happen when using [Direct Uploads](#direct-uploads). You can query for unattached records using the [unattached scope](https://github.com/rails/rails/blob/8ef5bd9ced351162b673904a0b77c7034ca2bc20/activestorage/app/models/active_storage/blob.rb#L49). Below is an example using a [custom rake task](command_line.html#custom-rake-tasks).
+
+```ruby
+namespace :active_storage do
+  desc "Purges unattached Active Storage blobs. Run regularly."
+  task purge_unattached: :environment do
+    ActiveStorage::Blob.unattached.where("active_storage_blobs.created_at <= ?", 2.days.ago).find_each(&:purge_later)
+  end
+end
+```
+
+WARNING: The query generated by `ActiveStorage::Blob.unattached` can be slow and potentially disruptive on applications with larger databases.