From d2ff19c39c097aa17d16e33c8de981f43cd1ffa0 Mon Sep 17 00:00:00 2001
From: David Heinemeier Hansson <david@loudthinking.com>
Date: Mon, 3 Jul 2017 20:14:28 +0200
Subject: WIP: Disk URLs

---
 lib/active_file/blob.rb            |  3 +++
 lib/active_file/disk_controller.rb | 20 ++++++++++++++++
 lib/active_file/railtie.rb         | 15 +++++++++++-
 lib/active_file/sites/disk_site.rb | 48 ++++++++++++++++++++++++++++++++++++++
 4 files changed, 85 insertions(+), 1 deletion(-)
 create mode 100644 lib/active_file/disk_controller.rb

(limited to 'lib')

diff --git a/lib/active_file/blob.rb b/lib/active_file/blob.rb
index 5a82edee65..3cb98656f2 100644
--- a/lib/active_file/blob.rb
+++ b/lib/active_file/blob.rb
@@ -32,6 +32,9 @@ class ActiveFile::Blob < ActiveRecord::Base
   def filename
     ActiveFile::Filename.new(self[:filename])
   end
+
+  def url(disposition: :inline, expires_in: 5.minutes)
+    site.url key, disposition: disposition, expires_in: expires_in
   end
 
 
diff --git a/lib/active_file/disk_controller.rb b/lib/active_file/disk_controller.rb
new file mode 100644
index 0000000000..7d94b02f5c
--- /dev/null
+++ b/lib/active_file/disk_controller.rb
@@ -0,0 +1,20 @@
+# FIXME: To be used by DiskSite#url
+class ActiveFile::DiskController < ActionController::Base
+  def show
+    if verified_key.expired?
+      head :gone
+    else
+      blob = ActiveFile::Blob.find_by!(key: verified_key.to_s)
+      send_data blob.download, filename: blob.filename, type: blob.content_type, disposition: disposition_param
+    end
+  end
+
+  private
+    def verified_key
+      ActiveFile::Sites::DiskSite::VerifiedKeyWithExpiration.new(params[:id])
+    end
+
+    def disposition_param
+      params[:disposition].presence_in(%w( inline attachment )) || 'inline'
+    end
+end
diff --git a/lib/active_file/railtie.rb b/lib/active_file/railtie.rb
index e1b34f56cf..4398bb6072 100644
--- a/lib/active_file/railtie.rb
+++ b/lib/active_file/railtie.rb
@@ -1,6 +1,19 @@
 require "rails/railtie"
 
 module ActiveFile
-  class Engine < ::Rails::Engine
+  class Railtie < Rails::Railtie # :nodoc:
+    config.action_cable = ActiveSupport::OrderedOptions.new
+
+    config.eager_load_namespaces << ActiveFile
+
+    initializer "action_cable.routes" do
+      require "active_file/disk_controller"
+
+      config.after_initialize do |app|
+        app.routes.prepend do
+          get "/rails/blobs/:id" => "active_file/disk#show", as: :rails_disk_blob
+        end
+      end
+    end
   end
 end
diff --git a/lib/active_file/sites/disk_site.rb b/lib/active_file/sites/disk_site.rb
index ee39b7a736..da1e69df03 100644
--- a/lib/active_file/sites/disk_site.rb
+++ b/lib/active_file/sites/disk_site.rb
@@ -2,6 +2,42 @@ require "fileutils"
 require "pathname"
 
 class ActiveFile::Sites::DiskSite < ActiveFile::Site
+  class_attribute :verifier, default: -> { Rails.application.message_verifier('ActiveFile::DiskSite') }
+
+  class << self
+    def generate_verifiable_key(key, expires_in:)
+      VerifiedKeyWithExpiration
+    end
+  end
+
+  class VerifiableKeyWithExpiration
+    def initialize(verifiable_key_with_expiration)
+      verified_key_with_expiration = ActiveFile::Sites::DiskSite.verify(verifiable_key_with_expiration)
+
+      @key        = verified_key_with_expiration[:key]
+      @expires_at = verified_key_with_expiration[:expires_at]
+    end
+
+    def expired?
+      @expires_at && Time.now.utc > @expires_at
+    end
+
+    def decoded
+      key
+    end
+  end
+
+  class VerifiedKeyWithExpiration
+    def initialize(key, expires_in: nil)
+      @key = key
+      @expires_at = Time.now.utc.advance(sec: expires_in)
+    end
+
+    def encoded
+      ActiveFile::Sites::DiskSite.verify.generate({ key: @key, expires_at: @expires_at })
+    end
+  end
+
   attr_reader :root
 
   def initialize(root:)
@@ -38,6 +74,14 @@ class ActiveFile::Sites::DiskSite < ActiveFile::Site
   end
 
 
+  def url(key, disposition:, expires_in: nil)
+    if defined?(Rails)
+      Rails.application.routes.url_helpers.rails_disk_blob_path(key)
+    else
+      "/rails/blobs/#{key}"
+    end
+  end
+
   def byte_size(key)
     File.size path_for(key)
   end
@@ -48,6 +92,10 @@ class ActiveFile::Sites::DiskSite < ActiveFile::Site
 
 
   private
+    def verifiable_key_with_expiration(key, expires_in: nil)
+      verifier.generate key: key, expires_at: Time.now.utc.advance(sec: expires_in)
+    end
+
     def path_for(key)
       File.join root, folder_for(key), key
     end
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