s3-upload.html

<link rel="import" href="../bower_components/polymer/polymer.html">

<polymer-element name="polymer-file-upload"  attributes="">
  <template>
    <style>
      /* styles for the custom element itself - lowest specificity */
      :host { display: block; }
      /* 
      style if an ancestor has the different class
      :host(.different) { } 
      */
    </style>
    <div class='s3-upload-controls row'>
      <input id="FileUpload" type="file" class="hidden s3-file-upload no-select" on-change="{{FileUploadChangeHandler}}">
      <div class="btn-group col-md-12 col-sm-12 col-xs-12 col-lg-12">
        <button id="FileUploadButton" class="btn btn-default col-md-11 col-sm-10 col-xs-10 col-lg-11 s3-file-upload-button" on-click="{{FileUploadButtonClickHandler}}">Upload</button>
        <button class='btn btn-default col-md-1 col-sm-2 col-xs-2 col-lg-1 s3-user-config-button'>
          <span class='glyphicon glyphicon-cog'></span>
        </button>
      </div>
    </div>
  </template>
  <script>
    var UUID = function (){
        var d = new Date().getTime();
        var uuid = 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
            var r = (d + Math.random()*16)%16 | 0;
            d = Math.floor(d/16);
            return (c=='x' ? r : (r&0x7|0x8)).toString(16);
        });
        return uuid;
    };

    Polymer("polymer-file-upload", {
      //applyAuthorStyles: true,
      //resetStyleInheritance: true,

      FileUploadChangeHandler: function(event){
        console.log(event);
        var file = event.currentTarget.files[0];
        var button = this.$.FileUploadButton;
        button.classList.add("disabled");
        button.innerHTML = "Preparing to transfer " + file.name + "...";
        var reader = new FileReader;
        var fileData = {
          name:file.name,
          size:file.size,
          type:file.type
        };

        reader.onload = function (e) {
          fileData.data = new Uint8Array(reader.result);
          fileData.originalName = fileData.name;
          var extension = (fileData.name).match(/\.[0-9a-z]{1,5}$/i);
          fileData.name = UUID()+extension; // Using a UUID instead of the name ensures that no spaces will end up in the filename
          options = {};
          options.file = fileData;
          // Session.set('s3-file-name', fileData.name)
          // Meteor.call("S3upload", options)
          // Send to S3 (how?)
          console.log(options);
        };

        reader.readAsArrayBuffer(file);
      },
      FileUploadButtonClickHandler: function(event){
        this.$.FileUpload.click();
      },
      // element is fully prepared
      ready: function(){ },
      // instance of the element is created
      created: function() { },
      // instance was inserted into the document
      enteredView: function() { },
      // instance was removed from the document
      leftView: function() { },
      // attribute added, removed or updated
      attributeChanged: function(attrName, oldVal, newVal) {
        console.log(attrName);
      }
    });
  </script>
</polymer-element>