Using the Trix Editor plus Private File Upload Attachments to S3

_photo.json.jbuilder

json.extract! photo, :id, :image_data, :created_at, :updated_at
json.url photo_url(photo, format: :html)
json.image_url image_url_photo_url(photo)

photos_controller.rb

class PhotosController < ApplicationController
  before_action :set_photo, only: [:show, :edit, :update, :destroy, :image_url]
  ...
  def image_url
    redirect_to @photo.image.url
  end
  ...
end

routes.rb

Rails.application.routes.draw do
...
  resources :photos do
    get "image_url", on: :member
  end
...
end

trix_uploads.js

// Turn off the default Trix captions
Trix.config.attachments.preview.caption = {
  name: false,
  size: false
};

function uploadAttachment(attachment) {
  var options = {
    extension: attachment.file.name.match(/(\.\w+)?$/)[0],                        //Set the file extension
    _: Date.now()                                                                 //Prevent Caching
  };
  $.getJSON("/images/upload/cache/presign", options, function(result) {
    // Create our form data to submit
    var file = attachment.file;
    var form = new FormData;
    form.append("key", result['fields']['key']);
    form.append("policy", result['fields']['policy']);
    form.append("x-amz-credential", result['fields']['x-amz-credential']);
    form.append("x-amz-algorithm", result['fields']['x-amz-algorithm']);
    form.append("x-amz-date", result['fields']['x-amz-date']);
    form.append("x-amz-signature", result['fields']['x-amz-signature']);
    form.append("file", file);
    // Create our XHR request
    var xhr = new XMLHttpRequest;
    xhr.open("POST", result['url'], true);

    // Report file uploads back to Trix
    xhr.upload.onprogress = function (event) {
      var progress = event.loaded / event.total * 100;
      attachment.setUploadProgress(progress);
    }

    // Tell Trix what url and href to use on successful upload
    xhr.onload = function () {
      if (xhr.status === 204) {
        var image = {
          id: result['fields']['key'].match(/cache\/(.+)/)[1],
          storage: "cache",
          metadata: {
            size: attachment.filesize,
            filename: attachment.filename,
            mime_type: attachment.contentType
          }
        };
        rails_form = new FormData;
        rails_form.append("photo[image]", JSON.stringify(image));
        $.ajax("/photos", {
          contentType: false,
          processData: false,
          data: rails_form,
          method: 'POST',
          dataType: 'json'
        }).done(function(data){
          return attachment.setAttributes({
            url: data.image_url,
            href: data.url
          })
        });
      }
    }
    return xhr.send(form);
  });
}

// Listen for the Trix attachment event to trigger upload
document.addEventListener("trix-attachment-add", function(event) {
  var attachment = event.attachment;
  if (attachment.file) {
    return uploadAttachment(attachment);
  }
});

Hello Neil, I'm also trying to build trix to work with S3 direct uploads. Will this work so that images are private? meaning it can't be seen by anyone else but the uploader? (I'm a rails newbie and a js newbie. I do need something that can be shared.)

uploads to s3 works , but i have a little problem related with expire url from S3

function uploadAttachment(attachment){
    let BASE_URL = window.location.origin;

    let file = attachment.file;
    let form = new FormData();
    form.append("Content-Type", file.type);
    form.append("photo[image_data]", file);
    let xhr  = new XMLHttpRequest;
    xhr.open("POST", "/photos.json", true);
    xhr.setRequestHeader("X-CSRF-Token", $.rails.csrfToken());
    xhr.upload.onprogress = function (event) {
        let progress = event.loaded / event.total * 100;
        attachment.setUploadProgress(progress);
    }
    xhr.onload = function(){
        if (xhr.status === 201) {
            console.log(xhr.status)
            let data = JSON.parse(xhr.responseText);
            return  attachment.setAttributes({
                url: `${BASE_URL}/photos/${data.id}/image_url`,
                href: `${BASE_URL}/photos/${data.id}/image_url`
            })

        }
    }
    return xhr.send(form);
}
document.addEventListener("trix-attachment-add", function(event) {
    let attachment = event.attachment;
    if (attachment.file) {
        return uploadAttachment(attachment);
    }

});

it's work for me

function uploadAttachment(attachment){
    let BASE_URL = window.location.origin;

    let file = attachment.file;
    let form = new FormData();
    form.append("Content-Type", file.type);
    form.append("photo[image_data]", file);
    let xhr  = new XMLHttpRequest;
    xhr.open("POST", "/photos.json", true);
    xhr.setRequestHeader("X-CSRF-Token", $.rails.csrfToken());
    xhr.upload.onprogress = function (event) {
        let progress = event.loaded / event.total * 100;
        attachment.setUploadProgress(progress);
    }
    xhr.onload = function(){
        if (xhr.status === 201) {
            console.log(xhr.status)
            let data = JSON.parse(xhr.responseText);
            return  attachment.setAttributes({
                url: `${BASE_URL}/photos/${data.id}/image_url`,
                href: `${BASE_URL}/photos/${data.id}/image_url`
            })

        }
    }
    return xhr.send(form);
}
document.addEventListener("trix-attachment-add", function(event) {
    let attachment = event.attachment;
    if (attachment.file) {
        return uploadAttachment(attachment);
    }

});

it's work for me

this looks like your url is your local file not your aws file?