How to send a “multipart/form-data” POST in Android with Volley

android, android-volley, http

Solution

I might be wrong on this but I think you need to implement your own `com.android.volley.toolbox.HttpStack` for this because the default ones (`HurlStack` if version > Gingerbread or `HttpClientStack`) don't deal with `multipart/form-data`.

Edit:

And indeed I was wrong. I was able to do it using `MultipartEntity` in Request like this:

public class MultipartRequest extends Request<String> {

    private MultipartEntity entity = new MultipartEntity();

    private static final String FILE_PART_NAME = "file";
    private static final String STRING_PART_NAME = "text";

    private final Response.Listener<String> mListener;
    private final File mFilePart;
    private final String mStringPart;

    public MultipartRequest(String url, Response.ErrorListener errorListener, Response.Listener<String> listener, File file, String stringPart)
    {
        super(Method.POST, url, errorListener);

        mListener = listener;
        mFilePart = file;
        mStringPart = stringPart;
        buildMultipartEntity();
    }

    private void buildMultipartEntity()
    {
        entity.addPart(FILE_PART_NAME, new FileBody(mFilePart));
        try
        {
            entity.addPart(STRING_PART_NAME, new StringBody(mStringPart));
        }
        catch (UnsupportedEncodingException e)
        {
            VolleyLog.e("UnsupportedEncodingException");
        }
    }

    @Override
    public String getBodyContentType()
    {
        return entity.getContentType().getValue();
    }

    @Override
    public byte[] getBody() throws AuthFailureError
    {
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        try
        {
            entity.writeTo(bos);
        }
        catch (IOException e)
        {
            VolleyLog.e("IOException writing to ByteArrayOutputStream");
        }
        return bos.toByteArray();
    }

    @Override
    protected Response<String> parseNetworkResponse(NetworkResponse response)
    {
        return Response.success("Uploaded", getCacheEntry());
    }

    @Override
    protected void deliverResponse(String response)
    {
        mListener.onResponse(response);
    }
}

It's pretty raw but I tried it with an image and a simple string and it works. The response is a placeholder, doesn't make much sense to return a Response String in this case. I had problems using apache httpmime to use MultipartEntity so I used this https://code.google.com/p/httpclientandroidlib/ don't know if there's a better way. Hope it helps.

Edit

You can use httpmime without using httpclientandroidlib, the only dependency is httpcore.

Problem

Has anyone been able to accomplish sending a `multipart/form-data` POST in Android with Volley yet? I have had no success trying to upload an `image/png` using a POST request to our server and am curious if anyone has. I believe the default way to do this would be to override `public byte[] getPostBody()` in the `Request.java` class and attach the `File` there with a blank Header key for the boundary. However, converting my file to a `String` for the `Map<String, String> postParams` and then having it encoded again seems obtuse and not really elegant. Also I've been unsuccessful in my attempts. This is really the only thing holding us back from switching to this library. Anyway, all thoughts and answers are extremely appreciated. Thank you for your help.

Original source

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