How to Make Working POST Multipart Requests with Volley in Android?

Working POST Multipart Request with Volley Using Latest API

In Android development, sending multipart requests, such as uploading files and text data, is a common task. While HttpEntity is no longer available in newer API versions, there are still ways to achieve multipart requests using Volley.

Creating a Basic Multipart Request

To create a multipart request, we can extend Volley's Request class like so:

import com.android.volley.AuthFailureError;
import com.android.volley.NetworkResponse;
import com.android.volley.ParseError;
import com.android.volley.Request;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.HttpHeaderParser;

import java.util.Map;

class MultipartRequest extends Request<NetworkResponse> {
    // Listener for request response
    private final Response.Listener<NetworkResponse> mListener;
    // Listener for request error
    private final Response.ErrorListener mErrorListener;
    // Request headers
    private final Map<String, String> mHeaders;
    // Multipart mime type (e.g., "multipart/form-data; boundary=XXX")
    private final String mMimeType;
    // Request body as multipart
    private final byte[] mMultipartBody;

    // Constructor
    public MultipartRequest(String url, Map<String, String> headers, String mimeType, byte[] multipartBody,
                            Response.Listener<NetworkResponse> listener, Response.ErrorListener errorListener) {
        super(Method.POST, url, errorListener);
        this.mListener = listener;
        this.mErrorListener = errorListener;
        this.mHeaders = headers;
        this.mMimeType = mimeType;
        this.mMultipartBody = multipartBody;
    }

    // Getters and setters

    // Override getHeaders() if you need to add custom headers
    @Override
    public Map<String, String> getHeaders() throws AuthFailureError {
        return (mHeaders != null) ? mHeaders : super.getHeaders();
    }

    // Override getBodyContentType() to set the correct mime type for the multipart request
    @Override
    public String getBodyContentType() {
        return mMimeType;
    }

    // Override getBody() to return the multipart body
    @Override
    public byte[] getBody() throws AuthFailureError {
        return mMultipartBody;
    }

    // Override parseNetworkResponse() to parse the response as a NetworkResponse
    @Override
    protected Response<NetworkResponse> parseNetworkResponse(NetworkResponse response) {
        try {
            return Response.success(
                    response,
                    HttpHeaderParser.parseCacheHeaders(response));
        } catch (Exception e) {
            return Response.error(new ParseError(e));
        }
    }

    // Delivering response and error
    @Override
    protected void deliverResponse(NetworkResponse response) {
        mListener.onResponse(response);
    }

    @Override
    public void deliverError(VolleyError error) {
        mErrorListener.onErrorResponse(error);
    }
}

Building the Multipart Body

To build the multipart body, we can use the following steps:

byte[] multipartBody = new byte[0];
ByteArrayOutputStream bos = new ByteArrayOutputStream();
DataOutputStream dos = new DataOutputStream(bos);
try {
    // Text data
    buildTextPart(dos, "name", "John Doe");
    buildTextPart(dos, "email", "john.doe@email.com");

    // Image data
    Bitmap imageBitmap = BitmapFactory.decodeResource(context.getResources(), R.drawable.my_image);
    buildImagePart(dos, "image", imageBitmap);

} catch (IOException e) {
    e.printStackTrace();
}
multipartBody = bos.toByteArray();

Including the Multipart Body in the Request

Once the multipart body is built, we can include it in our MultipartRequest instance like so:

MultipartRequest request = new MultipartRequest(
        "my_url",
        null, // Headers
        "multipart/form-data",
        multipartBody,
        new Response.Listener<NetworkResponse>() {
            @Override
            public void onResponse(NetworkResponse response) {
                // Handle response
            }
        },
        new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                // Handle error
            }
        });

Adding Text Data to the Request

In addition to image data, you can also include text data in your request:

private void buildTextPart(DataOutputStream dataOutputStream, String name, String value) throws IOException {
    dataOutputStream.writeBytes(twoHyphens + boundary + lineEnd);
    dataOutputStream.writeBytes("Content-Disposition: form-data; name=\"" + name + "\"" + lineEnd);
    dataOutputStream.writeBytes(lineEnd);
    dataOutputStream.writeBytes(value);
    dataOutputStream.writeBytes(lineEnd);
}

Replace twoHyphens, boundary, and lineEnd with appropriate values from your code.

Complete Code Sample

The following code sample shows a complete modular implementation of a VolleyMultipartRequest class:

import com.android.volley.AuthFailureError;
import com.android.volley.NetworkResponse;
import com.android.volley.ParseError;
import com.android.volley.Request;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.HttpHeaderParser;

import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

public class VolleyMultipartRequest extends Request<NetworkResponse> {
    private final Response.Listener<NetworkResponse> mListener;
    private final Response.ErrorListener mErrorListener;
    private final Map<String, String> mHeaders;
    private final String mMimeType;
    private final byte[] mMultipartBody;

    public VolleyMultipartRequest(int method, String url, Response.Listener<NetworkResponse> listener,
                                  Response.ErrorListener errorListener) {
        super(method, url, errorListener);
        this.mListener = listener;
        this.mErrorListener = errorListener;
        this.mHeaders = null;
        this.mMimeType = null;
        this.mMultipartBody = null;
    }

    public VolleyMultipartRequest(String url, Map<String, String> headers, String mimeType, byte[] multipartBody,
                                  Response.Listener<NetworkResponse> listener, Response.ErrorListener errorListener) {
        super(Method.POST, url, errorListener);
        this.mListener = listener;
        this.mErrorListener = errorListener;
        this.mHeaders = headers;
        this.mMimeType = mimeType;
        this.mMultipartBody = multipartBody;
    }

    @Override
    public Map<String, String> getHeaders() throws AuthFailureError {
        return (mHeaders != null) ? mHeaders : super.getHeaders();
    }

    @Override
    public String getBodyContentType() {
        return mMimeType;
    }

    @Override
    public byte[] getBody() throws AuthFailureError {
        return mMultipartBody;
    }

    @Override
    protected Response<NetworkResponse> parseNetworkResponse(NetworkResponse response) {
        try {
            return Response.success(
                    response,
                    HttpHeaderParser.parseCacheHeaders(response));
        } catch (Exception e) {
            return Response.error(new ParseError(e));
        }
    }

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

    @Override
    public void deliverError(VolleyError error) {
        mErrorListener.onErrorResponse(error);
    }

    public static Map<String, DataPart> createMultipartRequestParts(Map<String, String> params, Map<String, DataPart> data) {
        Map<String, DataPart> multipartParams = new HashMap<>();
        for (Map.Entry<String, String> entry : params.entrySet()) {
            multipartParams.put(entry.getKey(), new DataPart(entry.getValue()));
        }
        for (Map.Entry<String, DataPart> entry : data.entrySet()) {
            multipartParams.put(entry.getKey(), entry.getValue());
        }
        return multipartParams;
    }

    public static byte[] createMultipartBody(Map<String, DataPart> data, String boundary) throws IOException {
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        DataOutputStream dos = new DataOutputStream(bos);
        for (Map.Entry<String, DataPart> entry : data.entrySet()) {
            buildTextPart(dos, entry.getKey(), entry.getValue().getContentType(), entry.getValue().getFileName(), entry.getValue().getData());
        }

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