how to add a cancel upload button to jquery-file-upload basic-plugin

问题

I'm using jquery-file-upload with Rails 4, I started from https://github.com/tors/jquery-fileupload-rails-paperclip-example. So I'm using jquery-rails, jquery-fileupload-rails and paperclip gems.

As I am not a crack on jquery or javascript, I'm trying to simplify and understand everything, changing code to make remote calls to rails with js.erb.

So that, the file list is a rails partial (_videos.html_erb) and index action in uploads controller has a index.js.erb to respond with js. And I have added $.get('/uploads'); in de fileupload done event to refresh the partial.

everything works well, unless the cancel button and I don't understand what I have to do and where.

This is what docs tell me:

How to cancel an upload

Uploads can be canceled by invoking the abort method on a jqXHR object:

var jqXHR = $('#fileupload').fileupload('send', {files: filesList})
    .error(function (jqXHR, textStatus, errorThrown) {
        if (errorThrown === 'abort') {
            alert('File Upload has been canceled');
        }
    });
$('button.cancel').click(function (e) {
    jqXHR.abort();
});

And this is my index.html.erb:

Here, for progress bar and text indications, I put code extracted form file-upload-basic-plugin

<div class="container">
<h2 id="titol">Upload file</h2>
<%= form_for Upload.new, :html => { :multipart => true, :id => "fileupload"  } do |f| %>
  <div class="row fileupload-buttonbar">
      <%= f.file_field :upload %>
      <button class="cancel">Cancel upload</button>
  </div>

  <hr/>
<% end %>

<div id="videos">
  <%= render partial: "videos" %>
</div>

<!--..........This is necessary even though I don't know why -->
<script id="template-upload" type="text/x-tmpl">
</script>

<!-- The template to display files available for download -->
<script id="template-download" type="text/x-tmpl">
</script>
<!--............................................................... -->

<script type="text/javascript" charset="utf-8">

  $('#fileupload').fileupload({
    dataType: 'json',
    add: function (e, data) {
        data.context = $('<p/>').text('Uploading...').appendTo(document.body);
        data.submit();
    },
    done: function (e, data) {
        data.context.text('Upload finished.');
        $.get('/uploads');
    }

  });

  $('#fileupload').fileupload({
    progressall: function (e, data) {
      $("#titol").text(data.loaded);
      var progress = parseInt(data.loaded / data.total * 100, 10);
      $('#progress .bar').css(
          'width', progress + '%');
      }
  });

</script>

I supose I have to put somthing like this "var xhr = "

  $('#fileupload').fileupload({
    dataType: 'json',
    add: function (e, data) {
        data.context = $('<p/>').text('Uploading...').appendTo(document.body);
        var xhr = data.submit();
    },
    done: function (e, data) {
        data.context.text('Upload finished.');
        $.get('/uploads');
    }

  });

and then

$(function () {

  $('button.cancel').click(function (e) {
    jqXHR.abort();
  });

})

but this doesn't work and the code from docs crash everywhere: filesList doesn't exist...etc

Well, I guess I need some basic guidance on jquery or javascript

Thanks in advance

回答1:

You can also call abort() on data to cancel individual in-progress uploads.

   $( '#fileUpload' ).fileupload( {
        dataType: 'json',
        add: function( e, data ) {
            var abortBtn = $( '<a/>' )
                .attr( 'href', 'javascript:void(0)' )
                .append( 'Abort' )
                .click( function() {
                    data.abort();
                    data.context.remove();
                } );

            data.context = $( '<div/>' )
                .appendTo( document.body );

            data.context.append( $( '<p/>' ) )
                .append( 'Uploading ' + data.files[0].name )
                .append( abortBtn );

            data.submit();
        },
        done: function( e, data ) {
            /* ... */
        }
    });

回答2:

The solution was in knowledge about javascript variables scope:

$(function () {

  var xhr;                    // <------------ initialize variable

  $('#fileupload').fileupload({
    dataType: 'json',
    add: function (e, data) {
        data.context = $('<p/>').text('Uploading...').appendTo(document.body);
        xhr = data.submit(); //<-------------- asign result to var xhr
    },
    done: function (e, data) {
        data.context.text('....

And simply, use xhr's abort method:

  $('button.cancel').click(function (e) {
    xhr.abort();
    alert("abortat");
  });

来源：https://stackoverflow.com/questions/26218571/how-to-add-a-cancel-upload-button-to-jquery-file-upload-basic-plugin