How to handle FineUploader POST request in Java in PlayFramework? - multipartform-data

Question

I am trying to integrate FineUploader in my play framework code. View part is set up properly and it is working fine.
I am not clear how to retrieve file in my controllers upload method. And other query parameters, qquuid, qqfilename, content-type e.tc.
Following is the dump of file upload request sent by FileUploader:-
Request Headers
Accept:application/json
Accept-Encoding:gzip, deflate
Accept-Language:en-US,en;q=0.8
Cache-Control:no-cache
Connection:keep-alive
Content-Length:1021645
Content-Type:multipart/form-data; boundary=----WebKitFormBoundaryk8BZISBKKjjqiWQ6
DNT:1
Host:localhost:9000
Origin:http://localhost:9000
Referer:http://localhost:9000/computers
User-Agent:Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/42.0.2311.152 Safari/537.36
X-Requested-With:XMLHttpRequest
Request Payload
------WebKitFormBoundaryk8BZISBKKjjqiWQ6
Content-Disposition: form-data; name="id"
593
------WebKitFormBoundaryk8BZISBKKjjqiWQ6
Content-Disposition: form-data; name="qquuid"
bafb6448-1a87-40cc-abae-9624f37131cc
------WebKitFormBoundaryk8BZISBKKjjqiWQ6
Content-Disposition: form-data; name="qqfilename"
Test.png
------WebKitFormBoundaryk8BZISBKKjjqiWQ6
Content-Disposition: form-data; name="qqtotalfilesize"
1020995
------WebKitFormBoundaryk8BZISBKKjjqiWQ6
Content-Disposition: form-data; name="qqfile"; filename="Test.png"
Content-Type: image/png
------WebKitFormBoundaryk8BZISBKKjjqiWQ6--

Answer 1

I eventually found out by exploring play apis, sample code below.
Http.MultipartFormData body = request().body().asMultipartFormData();
Http.MultipartFormData.FilePart uploadFilePart = body.getFile("qqfile");
String fileName = uploadFilePart.getFilename();
File file = uploadFilePart.getFile();
Map<String,String[]> dataPart = request().body().asMultipartFormData().asFormUrlEncoded();
Iterator it = dataPart.entrySet().iterator();
while (it.hasNext()) {
Map.Entry pair = (Map.Entry)it.next();
String[] values = (String[]) pair.getValue();
System.out.println(pair.getKey() + " = " + values[0]);
}

Answer 2

Previous comment by me indicated there might have been something wrong with the http post fineuploader was doing, but of course that was wrong. I was trying to adapt traditional endpoint example code into a Spring 4.x MVC controller and was getting empty FileItem list from Apache Commons FileUpload libraries. After downloading the source for Spring and debugging through it, found that Spring MVC was using same Apache Commons FileUpload libraries to consume the http post request BEFORE it reached my controller code. A second call to Apache's FileUpload.parseRequest returns an empty FileItem list because it was already consumed. I had to repurpose the controller code to make use of correct signatures for request params. I found it easiest to let the MVC framework to the parsing work for me. I was still able to use much of the example code for traditional endpoints after refactoring for this. For example, my controller
#RequestMapping(value="/assetUpload", method = RequestMethod.POST)
public void assetUpload(HttpServletRequest request, HttpServletResponse response, #RequestParam("qqfile") MultipartFile file) throws ServletException, IOException { ....
Modification of the rest of the code to produce my own class to replace FileItem (in my case called the class "FineUploaderItem"), refactor RequestParser and how the Multipart parsing was working got my server endpoint working. I was able to use all the private methods in the UploadReceiver class in my code with very little modification after this and it all worked.