HTTP file upload without actually using a file

Question

I am using Apache HttpComponents' HttpClient to upload files to a third party web interface. Code looks like this:

HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("UPLOAD_URL");
FileBody bin = new FileBody(file, filename, "text/csv", "UTF-8");
MultipartEntity reqEntity = new MultipartEntity();
reqEntity.addPart("Username", new StringBody("User"));
reqEntity.addPart("Password", new StringBody("Password"));
reqEntity.addPart("bin", bin);
httppost.setEntity(reqEntity);
HttpResponse response = httpclient.execute(httppost);

This is working as expected.

As this data is sensitive, I don't want it to be stored on the client side. (The program retrieves this data from a web service. I only created the file for the purpose of uploading it.)

So I'm looking for a way to not use a real file, but replace it was some kind of in-memory representation. I tried to use InputStreamBody instead, but those requests get denied by the third party system.

Any ideas how this can be done?

Answer 1

Looks like the problem with using InputStreamBody is the getContentLength method, which looks like this:

public long getContentLength() {
    return -1;
}

This results in a chunked HTTP POST (Transfer-Encoding: chunked), which seems to be not understood by that particular web interface. So, I ended up extending InputStreamBody like this:

public class NoFileBody extends InputStreamBody {

  private final long length;

  public NoFileBody(final InputStream in, final String mimeType, final String filename, final long length) {
    super(in, mimeType, filename);
    this.length = length;
  }

  @Override
  public long getContentLength() {
    return length;
  }

}