Question

My server receives multipart form data from a mobile app. The result of printing out the request using request.content.toString(UTF_8) is shown below. The image is sent by the mobile as a base64-encoded string. How do I save the image data to file?

--*****org.apache.cordova.formBoundary
Content-Disposition: form-data; name="value1"

Furniture
--*****org.apache.cordova.formBoundary
Content-Disposition: form-data; name="value2"

Chair
--*****org.apache.cordova.formBoundary
Content-Disposition: form-data; name="file"; filename="image.jpg"
Content-Type: image/jpeg

����JFIF��XExifMM*�i...rest of image goes here...
--*****org.apache.cordova.formBoundary--

Answer 1

I am yet to parse the multipart form data, but saving the image turned out to be easy (once you know how). To test, I’m uploading only the image during testing using:

curl -T "image.jpg" http://127.0.0.1:8080/imageupload

I’m using Finagle, which depends on the netty libraries, so the request.content() returns a object of type org.jboss.netty.buffer.ChannelBuffer, for which you extract the image data as follows:

To save the file from the request content to file:

  val raf = new java.io.RandomAccessFile("image.jpg", "rw");
  val buf = request.getContent();
  val fChannel = raf.getChannel();

  fChannel.write( buf.toByteBuffer() );
  raf.close();
  fChannel.close();

To pass the request content on to a web service expecting base64binary:

  import org.jboss.netty.util.CharsetUtil._
  import org.jboss.netty.handler.codec.base64.Base64

  val base64binaryImage = (Base64.encode(request.getContent())).toString(UTF_8)