Rails 7 importmaps dropzone.js direct upload ActiveStorage

README.md

• Rails 7.0.2
• stimulus js
• importmaps
• dropzone.js
• direct upload ActiveStorage

This is simple implementation of technologies in hobby project of mine built in Rails7 where I need direct upload to S3.

make sure you configure CORS on the S3 bucket otherwise it will not work!!! => s3 bucket cors rails direct upload

note: JS implementation of this gist is not the best. I just copied it from some article (probably this one) and altered it so it fits into Stimulus controller with bunch of duplications. I'm gret with Ruby & Rails I'm not good with JavaScript

bin/importmap pin dropzone

application.html.slim

-# app/views/layouts/application.html.slim
doctype html
html
  head
    meta content=("text/html; charset=UTF-8") http-equiv="Content-Type" /
    title Moments
    = csrf_meta_tags
    = csp_meta_tag
    = stylesheet_link_tag "application", "data-turbo-track": "reload"
    = javascript_importmap_tags
    meta content="width=device-width, initial-scale=1" name="viewport" /
    
    -# I'm loading dropzone css here as a muppet. Feel free to place it to sprocket asset folder or use content_for tag
    link rel="stylesheet" href="https://unpkg.com/dropzone@5/dist/min/dropzone.min.css" type="text/css"
  body

application_helper.rb

# app/helpers/application_helper.rb

module ApplicationHelper

  def dropzone_controller_div
    data = {
      controller: "dropzone",
      'dropzone-max-file-size'=>"8",
      'dropzone-max-files' => "10",
      'dropzone-accepted-files' => 'image/jpeg,image/jpg,image/png,image/gif',
      'dropzone-dict-file-too-big' => "Váš obrázok ma veľkosť {{filesize}} ale povolené sú len obrázky do veľkosti {{maxFilesize}} MB",
      'dropzone-dict-invalid-file-type' => "Nesprávny formát súboru. Iba obrazky .jpg, .png alebo .gif su povolene",
    }

    content_tag :div, class: 'dropzone dropzone-default dz-clickable', data: data do
      yield
    end
  end
end

bucket.rb

# app/models/bucket.rb
class Bucket < ApplicationRecord
  validates_presence_of :title
  has_many_attached :files
end

buckets_controller.rb

# app/controllers/buckets_controller.rb
class BucketsController < ApplicationController
  before_action :set_bucket, only: %i[ show edit update destroy ]
  
  # ...
  
  def edit
  end
  
  # ...
  private
    def set_bucket
      @bucket = Bucket.find(params[:id])
    end

    # Only allow a list of trusted parameters through.
    def bucket_params
      params.require(:bucket).permit( files: [])
    end
end
  

dropzone_controller.js

// app/javascript/controllers/dropzone_controller.js
import { Controller } from "@hotwired/stimulus"
import { DirectUpload } from "@rails/activestorage";
import { Dropzone } from "dropzone";


export default class extends Controller {
  static targets = ["input"];

  connect() {
    this.dropZone = this.createDropZone(this);
    this.hideFileInput();
    this.bindEvents();
    Dropzone.autoDiscover = false;
  }

  // Private
  hideFileInput() {
    this.inputTarget.disabled = true;
    this.inputTarget.style.display = "none";
  }

  bindEvents() {
    this.dropZone.on("addedfile", file => {
      setTimeout(() => {
        file.accepted && this.createDirectUploadController(this, file).start();
      }, 500);
    });

    this.dropZone.on("removedfile", file => {
      file.controller && this.removeElement(file.controller.hiddenInput);
    });

    this.dropZone.on("canceled", file => {
      file.controller && file.controller.xhr.abort();
    });
  }

  get headers() {
    return { "X-CSRF-Token": this.getMetaValue("csrf-token") };
  }

  get url() {
    return this.inputTarget.getAttribute("data-direct-upload-url");
  }

  get maxFiles() {
    return this.data.get("maxFiles") || 1;
  }

  get maxFileSize() {
    return this.data.get("maxFileSize") || 256;
  }

  get dictFileTooBig() {
    return this.data.get("dictFileTooBig") || "File sile is {{filesize}} but only files up to {{maxFilesize}} are allowed";
  }

  get dictInvalidFileType() {
    return this.data.get("dictInvalidFileType") || "Invalid file type";
  }

  get acceptedFiles() {
    return this.data.get("acceptedFiles");
  }

  get addRemoveLinks() {
    return this.data.get("addRemoveLinks") || true;
  }

  getMetaValue(name) {
    const element = this.findElement(document.head, `meta[name="${name}"]`);
    if (element) {
      return element.getAttribute("content");
    }
  }

  findElement(root, selector) {
    if (typeof root == "string") {
      selector = root;
      root = document;
    }
    return root.querySelector(selector);
  }

  removeElement(el) {
    if (el && el.parentNode) {
      el.parentNode.removeChild(el);
    }
  }

  createDirectUploadController(source, file) {
    return new DirectUploadController(source, file);
  }

  createDropZone(controller) {
    return new Dropzone(controller.element, {
      url: controller.url,
      headers: controller.headers,
      maxFiles: controller.maxFiles,
      maxFilesize: controller.maxFileSize,
      dictFileTooBig: controller.dictFileTooBig,
      dictInvalidFileType: controller.dictInvalidFileType,
      acceptedFiles: controller.acceptedFiles,
      addRemoveLinks: controller.addRemoveLinks,
      autoQueue: false
    });
  }
}

class DirectUploadController {
  constructor(source, file) {
    this.directUpload = this.createDirectUpload(file, source.url, this);
    this.source = source;
    this.file = file;
  }

  start() {
    this.file.controller = this;
    this.hiddenInput = this.createHiddenInput();
    this.directUpload.create((error, attributes) => {
      if (error) {
        this.removeElement(this.hiddenInput);
        this.emitDropzoneError(error);
      } else {
        this.hiddenInput.value = attributes.signed_id;
        this.emitDropzoneSuccess();
      }
    });
  }

  createHiddenInput() {
    const input = document.createElement("input");
    input.type = "hidden";
    input.name = this.source.inputTarget.name;
    this.insertAfter(input, this.source.inputTarget);
    return input;
  }

  insertAfter(el, referenceNode) {
    return referenceNode.parentNode.insertBefore(el, referenceNode.nextSibling);
  }

  removeElement(el) {
    if (el && el.parentNode) {
      el.parentNode.removeChild(el);
    }
  }

  directUploadWillStoreFileWithXHR(xhr) {
    this.bindProgressEvent(xhr);
    this.emitDropzoneUploading();
  }

  bindProgressEvent(xhr) {
    this.xhr = xhr;
    this.xhr.upload.addEventListener("progress", event =>
      this.uploadRequestDidProgress(event)
    );
  }

  uploadRequestDidProgress(event) {
    const element = this.source.element;
    const progress = (event.loaded / event.total) * 100;
    this.findElement(
      this.file.previewTemplate,
      ".dz-upload"
    ).style.width = `${progress}%`;
  }

  findElement(root, selector) {
    if (typeof root == "string") {
      selector = root;
      root = document;
    }
    return root.querySelector(selector);
  }

  emitDropzoneUploading() {
    this.file.status = Dropzone.UPLOADING;
    this.source.dropZone.emit("processing", this.file);
  }

  emitDropzoneError(error) {
    this.file.status = Dropzone.ERROR;
    this.source.dropZone.emit("error", this.file, error);
    this.source.dropZone.emit("complete", this.file);
  }

  emitDropzoneSuccess() {
    this.file.status = Dropzone.SUCCESS;
    this.source.dropZone.emit("success", this.file);
    this.source.dropZone.emit("complete", this.file);
  }

  createDirectUpload(file, url, controller) {
    return new DirectUpload(file, url, controller);
  }
}

edit.html.slim

-# app/views/buckets/edit.html.slim

      = form_with model: @bucket do |f|
        = f.label :files, class: "label d-none"
        = dropzone_controller_div do
          - f.object.files.each do |file|
            = f.hidden_field :files, multiple: true, value: file.signed_id
          = f.file_field :files, direct_upload: true, multiple: true, 'data-dropzone-target': 'input'
          .dropzone-msg.dz-message.needsclick.text-gray-600
            h3.dropzone-msg-title Drag here to upload or click here to browse
            span.dropzone-msg-desc.text-sm 2 MB file size maximum. Allowed file types png, jpg.
        = f.button "Upload", class: 'btn-primary mt-2'

importmap.rb

# config/importmap.rb

pin "application"
pin "@hotwired/turbo-rails", to: "turbo.js"
pin "@hotwired/stimulus", to: "stimulus.js"
pin "@hotwired/stimulus-importmap-autoloader", to: "stimulus-importmap-autoloader.js"
pin_all_from "app/javascript/controllers", under: "controllers"

# Use direct uploads for Active Storage (remember to import "@rails/activestorage" in your application.js)
pin "@rails/activestorage", to: "activestorage.esm.js"

# added via  `bin/importmap pin dropzone`
pin "dropzone", to: "https://ga.jspm.io/npm:[email protected]/dist/dropzone.mjs"
pin "just-extend", to: "https://ga.jspm.io/npm:[email protected]/index.esm.js" # required by dropzone

s3 CORS

<Cors>
  <CorsRule>
    <AllowedOrigins>http://localhost:3000</AllowedOrigins>
    <AllowedMethods>PUT</AllowedMethods>
    <AllowedHeaders>Origin, Content-Type, Content-MD5, x-ms-blob-content-disposition, x-ms-blob-type</AllowedHeaders>
    <MaxAgeInSeconds>3600</MaxAgeInSeconds>
  </CorsRule>
</Cors>

show.html.slim

      - @bucket.files.each do |file|
        = image_tag(file.variant(resize_to_fill: [100, 100]))

alternative way how to load layout where CDN css for dropzone is loaded when we use dropzone_controller_div helper

-# app/views/layouts/application.html.slim
doctype html
html
  head
    meta content=("text/html; charset=UTF-8") http-equiv="Content-Type" /
    title Moments
    = csrf_meta_tags
    = csp_meta_tag
    = stylesheet_link_tag "application", "data-turbo-track": "reload"
    = javascript_importmap_tags
    meta content="width=device-width, initial-scale=1" name="viewport" /
    
    -# load dropzone CSS 
    yield :head_link
  body

# app/helpers/application_helper.rb

module ApplicationHelper

  def dropzone_controller_div
    content_for :head_link do
      tag :link, rel: "stylesheet", href: "https://unpkg.com/dropzone@5/dist/min/dropzone.min.css", type: "text/css"
    end

    data = {
      controller: "dropzone",
      'dropzone-max-file-size'=>"8",
      'dropzone-max-files' => "10",
      'dropzone-accepted-files' => 'image/jpeg,image/jpg,image/png,image/gif',
      'dropzone-dict-file-too-big' => "Váš obrázok ma veľkosť {{filesize}} ale povolené sú len obrázky do veľkosti {{maxFilesize}} MB",
      'dropzone-dict-invalid-file-type' => "Nesprávny formát súboru. Iba obrazky .jpg, .png alebo .gif su povolene",
    }

    content_tag :div, class: 'dropzone dropzone-default dz-clickable', data: data do
      yield
    end
  end
end

how it looks like

progress