ether Swarm upload and download

gistfile1.txt

 previewHash(hash){
        var preview = document.querySelector('img');
        var xhttp = new XMLHttpRequest();
        xhttp.onreadystatechange = function() {
            if (this.readyState == 4 && this.status == 200) {
               // Typical action to be performed when the document is ready:
                preview.src = xhttp.responseText;
            }
        };
        xhttp.open("GET", "http://swarm-gateways.net/bzz:/" + hash, true);
        xhttp.send();
    },

    uploadToSwarm() {
      var preview = document.querySelector('img');
      var file    = document.querySelector('input[type=file]').files[0];
      var reader  = new FileReader();

      reader.addEventListener("load", function () {
        //preview.src = reader.result;
        var xhr = new XMLHttpRequest();
        xhr.open("POST", "http://swarm-gateways.net/bzz:/", true);
        xhr.setRequestHeader('Content-Type', 'text/plain');
        xhr.send(reader.result);
        xhr.onload = function() {
          hash = this.responseText;
          console.log(hash);
        }
      }, false);

      if (file) {
        reader.readAsDataURL(file);
      }
    },