diff --git a/guacamole-common-js/src/main/resources/guacamole.js b/guacamole-common-js/src/main/resources/guacamole.js
index 2c59e996f..72c5fc3bc 100644
--- a/guacamole-common-js/src/main/resources/guacamole.js
+++ b/guacamole-common-js/src/main/resources/guacamole.js
@@ -297,6 +297,45 @@ Guacamole.Blob = function(mimetype, name) {
 };
 
 
+/**
+ * Abstract stream which can receive data.
+ * 
+ * @constructor
+ * @param {Guacamole.Client} client The client owning this stream.
+ * @param {Number} index The index of this stream.
+ */
+Guacamole.OutputStream = function(client, index) {
+
+    /**
+     * Reference to this stream.
+     * @private
+     */
+    var guac_stream = this;
+
+    /**
+     * The index of this stream.
+     * @type Number
+     */
+    this.index = index;
+
+    /**
+     * Writes the given base64-encoded data to this stream as a blob.
+     * 
+     * @param {String} data The base64-encoded data to send.
+     */
+    this.write = function(data) {
+        client.sendBlob(guac_stream.index, data);
+    };
+
+    /**
+     * Closes this stream.
+     */
+    this.close = function() {
+        client.endStream(guac_stream.index);
+    };
+
+};
+
 /**
  * Guacamole protocol client. Given a display element and {@link Guacamole.Tunnel},
  * automatically handles incoming and outgoing Guacamole instructions via the
@@ -580,6 +619,20 @@ Guacamole.Client = function(tunnel) {
         tunnel.sendMessage("end", index);
     };
 
+    /**
+     * Opens a new file for writing, having the given index, mimetype and
+     * filename.
+     * 
+     * @param {Number} index The index of the file to write to. This index must
+     *                       be unused.
+     * @param {String} mimetype The mimetype of the file being sent.
+     * @param {String} filename The filename of the file being sent.
+     */
+    this.createFileStream = function(index, mimetype, filename) {
+        guac_client.beginFileStream(index, mimetype, filename);
+        return new Guacamole.OutputStream(guac_client, index);
+    };
+
     /**
      * Fired whenever the state of this Guacamole.Client changes.
      * 
diff --git a/guacamole/src/main/webapp/scripts/client-ui.js b/guacamole/src/main/webapp/scripts/client-ui.js
index 80e4d23d7..37c43c882 100644
--- a/guacamole/src/main/webapp/scripts/client-ui.js
+++ b/guacamole/src/main/webapp/scripts/client-ui.js
@@ -1088,7 +1088,7 @@ GuacUI.Client.attach = function(guac) {
         reader.onloadend = function() {
 
             // Open file for writing
-            GuacUI.Client.attachedClient.beginFileStream(index, file.type, file.name);
+            var stream = GuacUI.Client.attachedClient.createFileStream(index, file.type, file.name);
 
             var bytes = new Uint8Array(reader.result);
             var offset = 0;
@@ -1100,14 +1100,14 @@ GuacUI.Client.attach = function(guac) {
                 var base64 = _get_base64(slice);
 
                 // "Write" packet
-                GuacUI.Client.attachedClient.sendBlob(index, base64);
+                stream.write(base64);
 
                 // Advance to next packet, or close if EOF
                 offset += 4096;
                 if (offset < bytes.length)
                     window.setTimeout(continueUpload, 500);
                 else
-                    GuacUI.Client.attachedClient.endStream(index);
+                    stream.close();
 
             };