Play 2.0.4 File upload not working? Always "MissingFilePart"

Question

I'm trying to implement file upload using the Play Framework 2 (Java)

To do this, I've followed the following guide: http://www.playframework.org/documentation/2.0/JavaFileUpload

On the server-side, I always get an object of MissingFilePart in the MultipartFormData.

This is my view:

@form(action = routes.ImmediateCollections.savePoliceReport, 'enctype -> "multipart/form-data") {
    <fieldset>
        <div class="fileupload fileupload-new">
            <span class="btn btn-file">
                <span class="fileupload-new">Select file</span>
                <span class="fileupload-exists">Change</span>
                <input type="file" name="policeReportFile" id="policeReportFile"/>
            </span>
            <span class="fileupload-preview"></span>
            <a href="#" class="close fileupload-exists" style="float: none">×</a>
        </div>
    </fieldset>
    @controls {
        @submitbutton()
    }
}

This generates the following html:

<form action="/immediatecollections/save-policereport" method="POST" enctype="multipart/form-data">
    <fieldset>
        <div class="fileupload fileupload-new">
            <span class="btn btn-file">
                <span class="fileupload-new">Select file</span>
                <span class="fileupload-exists">Change</span>
                <input type="file" name="policeReportFile" id="policeReportFile">
            </span>
            <span class="fileupload-preview"></span>
            <a href="#" class="close fileupload-exists" style="float: none">×</a>
        </div>
    </fieldset>
    <div class="control-group">
        <div class="controls">
            <input type="submit" class="btn btn-success" value="Save">
        </div>
    </div>
</form>

(For those wondering about the spans and divs, I'm using the excellent jasny bootstrap extensions.)

Note that I only have one input field. This form only serves one purpose: uploading 1 file.

This is my controller :

public static Result savePoliceReport() {
    Http.MultipartFormData formData = request().body().asMultipartFormData();
    Http.MultipartFormData.FilePart policeReportFile = formData.getFile("policeReportFile");
    if (policeReportFile != null) {
        // move file to somewhere
        // save metadata to database

        // for simplicity's sake: return json success = true or false
        ObjectNode jsonResult = Json.newObject();
        jsonResult.put("success", true);
        return ok(jsonResult);
    } else {
        ObjectNode jsonResult = Json.newObject();
        jsonResult.put("success", false);
        return badRequest(jsonResult);
    }
}

This method is defined like this in the routes file:

POST    /immediatecollections/save-policereport     controllers.ImmediateCollections.savePoliceReport

Now when I upload a file and debug on the server-side, this is what I get as request:

Server side debugging

If I'm reading this correctly, it says the file contents are missing. What happened? Did the bytes get lost in transmission? Why didn't Play throw an exception if something failed?

I've tried this in both Chrome and Internet Explorer, with both times the same result.

What am I doing wrong? Thanks!

Moeri Moeri · Accepted Answer · 2013-02-27T15:38:02

This was eventually solved on Google groups, I'll repost the answer from there:

James Roper:

MissingFilePart is thrown when the filename field in the multipart data is empty (the name is a bit misleading). Why a browser would be sending an empty file name, that's an interesting question. In the Chrome development tools Network tab, could you upload a small (only a few bytes) file, and then have a look in the request body? Could you post the request body here? It should look something like this:

--AaB03x content-disposition: form-data; name="pics"; filename="file1.txt" Content-Type: text/plain

This is the content of the uploaded file --AaB03x--

Another issue here is that while the HTML spec encourages clients to make a best effort to submit a filename parameter, it is not mandatory field, so Play shouldn't be failing if it's not there.

My Response:

You are correct, the filename was missing. It turns out that Jasny's javascript somehow broke the input element. I simply replaced it with a basic element without the fancy markup due to a lack of time, maybe I'll get back to this later. If anyone figures out a solution I'll be happy to hear it, but for now I'll leave it as it is.

Thanks for your reply James, it would have taken me considerably longer to find that error. :-)

TLDR: name attribute was missing in input tag

Play 2.0.4 File upload not working? Always "MissingFilePart"

2 Answers