使用 rails 中的活动存储直接上传 - input.dataset.directUploadUrl "undefined"

Question

使用 rails 6 并尝试将文件 using this drag and drop JS framework 上传到本地磁盘，但我收到“Failed to load resource: the server responded with a status of 404 (Not Found)”。这是由于未定义 url 变量。

控制台错误：ActionController::RoutingError (No route matches [POST] "/undefined"。

我已按照此处的所有步骤进行操作：https://edgeguides.rubyonrails.org/active_storage_overview.html。

JS代码：

import { DirectUpload } from "@rails/activestorage"
function uploadFile(file) {

const input = document.querySelector('input[type=file]')
console.log(input)

  // your form needs the file_field direct_upload: true, which
  //  provides data-direct-upload-url
  const url = input.dataset.directUploadUrl <-- returns "undefined"
  console.log(url)
  const upload = new DirectUpload(file, url)

  upload.create((error, blob) => {
    if (error) {
      // Handle the error
    } else {
      // Add an appropriately-named hidden input to the form with a
      //  value of blob.signed_id so that the blob ids will be
      //  transmitted in the normal upload flow
      const hiddenField = document.createElement('input')
      hiddenField.setAttribute("type", "hidden");
      hiddenField.setAttribute("value", blob.signed_id);
      hiddenField.name = input.name
      document.querySelector('form').appendChild(hiddenField)
    }
  })

HTML:

    <div id="drop-area">
      <form class="my-form">
        <p>Upload multiple files with the file dialog or by dragging and dropping images onto the dashed region</p>
        <input type="file" id="fileElem" multiple accept="image/*" onchange="handleFiles(this.files)" data-direct-upload = "true">
        <label class="button" for="fileElem">Select some files</label>
      </form>
      <progress id="progress-bar" max=100 value=0></progress>
      <div id="gallery" /></div>
    </div>

        <%= javascript_pack_tag 'dropzone.js' %>

我想知道活动存储是否不喜欢没有整齐地打包在嵌入式 ruby 代码中的表单数据，如下所示：

<%= form.file_field :attachments, multiple: true, direct_upload: true %>

方法二：如果我尝试在不使用活动存储 DirectUpload 方法的情况下发送文件，我会收到“无法加载资源：服务器响应状态为 400（错误请求）”，控制台输出为 ActionController::ParameterMissing (param is missing or the value is empty: blob)

这是 JS 代码：

function uploadFile(file, i) {
  var url2 = 'rails/active_storage/direct_uploads'
  var xhr = new XMLHttpRequest()
  var formData = new FormData()
  xhr.open('POST', url2, true)
  xhr.setRequestHeader('X-Requested-With', 'XMLHttpRequest')

   //Update progress (can be used to show progress indicator)
  xhr.upload.addEventListener("progress", function(e) {
    updateProgress(i, (e.loaded * 100.0 / e.total) || 100)
  })

  xhr.addEventListener('readystatechange', function(e) {
    if (xhr.readyState == 4 && xhr.status == 200) {
      updateProgress(i, 100) // <- Add this
    }
    else if (xhr.readyState == 4 && xhr.status != 200) {
      // Error. Inform the user
    }
  })

  formData.append('upload_preset', 'ujpu6gyk')
  formData.append('file', file)
  xhr.send(formData)
}

在研究了 URL 的使用方法后，'rails/active_storage/direct_uploads' 似乎越过了 404 消息，而是抛出了 400。我无法相信仅仅上传一个文件就这么困难到本地磁盘。请帮忙！

Answer 1

所以我并没有加深对主动存储的理解，但我确实找到了一个有效的解决方案。在方法 1 中，我只是将返回“未定义”的 URL 更改为手动 'rails/active_storage/direct_uploads'.

JS 代码现在看起来像：

function uploadFile(file) {

// const input = document.querySelector('input[type=file]')
// console.log(input)

  // your form needs the file_field direct_upload: true, which
  //  provides data-direct-upload-url
  const url = 'rails/active_storage/direct_uploads' //input.dataset.directUploadUrl 
  console.log(url)
  const upload = new DirectUpload(file, url)

  upload.create((error, blob) => {
    if (error) {
      // Handle the error
    } else {
      // Add an appropriately-named hidden input to the form with a
      //  value of blob.signed_id so that the blob ids will be
      //  transmitted in the normal upload flow
      const hiddenField = document.createElement('input')
      hiddenField.setAttribute("type", "hidden");
      hiddenField.setAttribute("value", blob.signed_id);
      hiddenField.name = input.name
      document.querySelector('form').appendChild(hiddenField)
    }
  })

上传后，我可以像这样（从 Ruby 中）对文件进行 blob 操作，而无需将它们下载到临时目录：

blob = ActiveStorage::Blob.first
        blob.open do |tempfile|
          puts tempfile.path  #do some processing
          puts blob.filename
        end

Answer 2

当你使用 erb 助手时，我刚刚运行遇到了类似的问题

 <%= form.file_field :images, direct_upload: true %>

生成的输入包含数据直接上传-url，就像这样

<input data-direct-upload-url="http://localhost:3000/rails/active_storage/direct_uploads" type="file" name="post[images]" id="post_images">

在我的例子中，页面上已经有一些其他文件输入，因此来自活动存储示例的默认查询 select

const input = document.querySelector('input[type=file]')

在没有直接上传的情况下返回另一个输入 url，导致出现与您遇到的类似的错误。

使用 rails 中的活动存储直接上传 - input.dataset.directUploadUrl "undefined"

direct upload using active storage in rails - input.dataset.directUploadUrl "undefined"

javascript

ruby

ruby-on-rails

jrubyonrails

rails-activestorage