Refresh attachments with virus scan result

app/controllers/attachments_controller.rb

@@ -0,0 +1,9 @@
+class AttachmentsController < ApplicationController
+  before_action :authenticate_logged_user!
+  include ActiveStorage::SetBlob
+
+  def show
+    @attachment = @blob.attachments.find(params[:id])
+    @user_can_upload = params[:user_can_upload]
+  end
+end

app/javascript/packs/application.js

@@ -9,6 +9,7 @@ import ReactUJS from '../shared/react-ujs';
 import reactComponents from '../shared/react-components';
 
 import '../shared/activestorage/ujs';
+import '../shared/activestorage/attachment-checker';
 import '../shared/rails-ujs-fix';
 import '../shared/safari-11-file-xhr-workaround';
 import '../shared/autocomplete';

app/javascript/shared/activestorage/attachment-checker.js

@@ -0,0 +1,66 @@
+import Rails from 'rails-ujs';
+
+addEventListener('turbolinks:load', () => {
+  checker.deactivate();
+
+  const attachments = document.querySelectorAll('[data-attachment-check-url]');
+
+  for (let attachment of attachments) {
+    checker.add(attachment.dataset.attachmentCheckUrl);
+  }
+});
+
+addEventListener('attachment:update', ({ detail: { url } }) => {
+  checker.add(url);
+});
+
+class AttachmentChecker {
+  urls = new Set();
+  timeout;
+  checks = 0;
+
+  constructor(settings = {}) {
+    this.interval = settings.interval || 5000;
+    this.maxChecks = settings.maxChecks || 5;
+  }
+
+  get isEnabled() {
+    return this.checks <= this.maxChecks;
+  }
+
+  get isActive() {
+    return this.timeout !== undefined;
+  }
+
+  add(url) {
+    if (this.isEnabled) {
+      if (!this.isActive) {
+        this.activate();
+      }
+      this.urls.add(url);
+    }
+  }
+
+  activate() {
+    this.timeout = setTimeout(() => {
+      for (let url of this.urls) {
+        Rails.ajax({ url, type: 'get' });
+      }
+      this.checks++;
+      this.reset();
+    }, this.interval);
+  }
+
+  deactivate() {
+    this.checks = 0;
+    this.reset();
+  }
+
+  reset() {
+    clearTimeout(this.timeout);
+    this.urls = new Set();
+    this.timeout = undefined;
+  }
+}
+
+const checker = new AttachmentChecker();

app/views/attachments/show.js.erb

@@ -0,0 +1,8 @@
+<%= render_to_element(".pj-link[data-attachment-id=\"#{@attachment.id}\"]",
+  partial: 'shared/attachment/show',
+  outer: true,
+  locals: { attachment: @attachment, user_can_upload: @user_can_upload }) %>
+
+<% if @attachment.virus_scanner.pending? %>
+  <%= fire_event('attachment:update', { url: attachment_url(@attachment.id, { signed_id: @attachment.blob.signed_id, user_can_upload: @user_can_upload }) }.to_json ) %>
+<% end %>

config/routes.rb

@@ -133,6 +133,8 @@ Rails.application.routes.draw do
     post ':position/repetition', to: 'repetition#show', as: :repetition
   end
 
+  get 'attachments/:id', to: 'attachments#show', as: :attachment
+
   get 'tour-de-france' => 'root#tour_de_france'
   get "patron" => "root#patron"
   get "accessibilite" => "root#accessibilite"