Envío de archivos mediante POST con HttpURLConnection

Dado que los desarrolladores de Android recomiendan usar la HttpURLConnectionclase, me preguntaba si alguien puede proporcionarme un buen ejemplo sobre cómo enviar un "archivo" de mapa de bits (en realidad un flujo en memoria) a través de POST a un servidor HTTP Apache. No me interesan las cookies, la autenticación ni nada complicado, pero solo quiero tener una implementación confiable y lógica. Todos los ejemplos que he visto por aquí se parecen más a "intentemos esto y tal vez funcione".

En este momento, tengo este código:

URL url;
HttpURLConnection urlConnection = null;
try {
    url = new URL("http://example.com/server.cgi");

    urlConnection = (HttpURLConnection) url.openConnection();

} catch (Exception e) {
    this.showDialog(getApplicationContext(), e.getMessage());
}
finally {
    if (urlConnection != null)
    {
        urlConnection.disconnect();
    }
}

donde showDialog solo debe mostrar un AlertDialog(en caso de una URL no válida?).

Ahora, digamos que genero un mapa de bits como este: Bitmap image = this.getBitmap()dentro de un control derivado de Viewy quiero enviarlo a través de POST. ¿Cuál sería el procedimiento adecuado para lograr tal cosa? ¿Qué clases necesito usar? ¿Puedo usar HttpPostlike en este ejemplo ? Si es así, ¿cómo construiría el InputStreamEntitypara mi mapa de bits? Me resultaría repugnante que se requiera almacenar primero el mapa de bits en un archivo en el dispositivo.

También debo mencionar que realmente necesito enviar cada píxel inalterado del mapa de bits original al servidor, por lo que no puedo convertirlo a JPEG.

No tengo idea de por qué la HttpURLConnectionclase no proporciona ningún medio para enviar archivos sin tener que componer el contenedor de archivos manualmente. Esto es lo que terminé haciendo, pero si alguien conoce una mejor solución, hágamelo saber.

Datos de entrada:

Bitmap bitmap = myView.getBitmap();

Material estático:

String attachmentName = "bitmap";
String attachmentFileName = "bitmap.bmp";
String crlf = "\r\n";
String twoHyphens = "--";
String boundary =  "*****";

Configurar la solicitud:

HttpURLConnection httpUrlConnection = null;
URL url = new URL("http://example.com/server.cgi");
httpUrlConnection = (HttpURLConnection) url.openConnection();
httpUrlConnection.setUseCaches(false);
httpUrlConnection.setDoOutput(true);

httpUrlConnection.setRequestMethod("POST");
httpUrlConnection.setRequestProperty("Connection", "Keep-Alive");
httpUrlConnection.setRequestProperty("Cache-Control", "no-cache");
httpUrlConnection.setRequestProperty(
    "Content-Type", "multipart/form-data;boundary=" + this.boundary);

Iniciar contenedor de contenido:

DataOutputStream request = new DataOutputStream(
    httpUrlConnection.getOutputStream());

request.writeBytes(this.twoHyphens + this.boundary + this.crlf);
request.writeBytes("Content-Disposition: form-data; name=\"" +
    this.attachmentName + "\";filename=\"" + 
    this.attachmentFileName + "\"" + this.crlf);
request.writeBytes(this.crlf);

Convierte Bitmapa ByteBuffer:

//I want to send only 8 bit black & white bitmaps
byte[] pixels = new byte[bitmap.getWidth() * bitmap.getHeight()];
for (int i = 0; i < bitmap.getWidth(); ++i) {
    for (int j = 0; j < bitmap.getHeight(); ++j) {
        //we're interested only in the MSB of the first byte, 
        //since the other 3 bytes are identical for B&W images
        pixels[i + j] = (byte) ((bitmap.getPixel(i, j) & 0x80) >> 7);
    }
}

request.write(pixels);

Contenedor de contenido final:

request.writeBytes(this.crlf);
request.writeBytes(this.twoHyphens + this.boundary + 
    this.twoHyphens + this.crlf);

Búfer de salida de lavado:

request.flush();
request.close();

Obtener una respuesta:

InputStream responseStream = new 
    BufferedInputStream(httpUrlConnection.getInputStream());

BufferedReader responseStreamReader = 
    new BufferedReader(new InputStreamReader(responseStream));

String line = "";
StringBuilder stringBuilder = new StringBuilder();

while ((line = responseStreamReader.readLine()) != null) {
    stringBuilder.append(line).append("\n");
}
responseStreamReader.close();

String response = stringBuilder.toString();

Cerrar flujo de respuesta:

responseStream.close();

Cierra la conexión:

httpUrlConnection.disconnect();

PD: Por supuesto, tuve que completar la solicitud private class AsyncUploadBitmaps extends AsyncTask<Bitmap, Void, String>para hacer feliz a la plataforma Android, porque no le gusta tener solicitudes de red en el hilo principal.

En realidad, encontré una mejor manera de enviar archivos usando HttpURLConnection usando MultipartEntity

private static String multipost(String urlString, MultipartEntity reqEntity) {
    try {
        URL url = new URL(urlString);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setReadTimeout(10000);
        conn.setConnectTimeout(15000);
        conn.setRequestMethod("POST");
        conn.setUseCaches(false);
        conn.setDoInput(true);
        conn.setDoOutput(true);

        conn.setRequestProperty("Connection", "Keep-Alive");
        conn.addRequestProperty("Content-length", reqEntity.getContentLength()+"");
        conn.addRequestProperty(reqEntity.getContentType().getName(), reqEntity.getContentType().getValue());

        OutputStream os = conn.getOutputStream();
        reqEntity.writeTo(conn.getOutputStream());
        os.close();
        conn.connect();

        if (conn.getResponseCode() == HttpURLConnection.HTTP_OK) {
            return readStream(conn.getInputStream());
        }

    } catch (Exception e) {
        Log.e(TAG, "multipart post error " + e + "(" + urlString + ")");
    }
    return null;        
}

private static String readStream(InputStream in) {
    BufferedReader reader = null;
    StringBuilder builder = new StringBuilder();
    try {
        reader = new BufferedReader(new InputStreamReader(in));
        String line = "";
        while ((line = reader.readLine()) != null) {
            builder.append(line);
        }
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        if (reader != null) {
            try {
                reader.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
    return builder.toString();
} 

Suponiendo que está cargando una imagen con datos de mapa de bits:

    Bitmap bitmap = ...;
    String filename = "filename.png";
    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    bitmap.compress(Bitmap.CompressFormat.PNG, 100, bos);
    ContentBody contentPart = new ByteArrayBody(bos.toByteArray(), filename);

    MultipartEntity reqEntity = new MultipartEntity(HttpMultipartMode.BROWSER_COMPATIBLE);
    reqEntity.addPart("picture", contentPart);
    String response = multipost("http://server.com", reqEntity);

¡Y voilá! Sus datos de publicación contendrán un campo de imagen junto con el nombre de archivo y la ruta en su servidor.

Para cargar archivos en el servidor con algún parámetro utilizando MultipartUtilityde manera simple.

MultipartUtility.java

public class MultipartUtility {

    private final String boundary;
    private static final String LINE_FEED = "\r\n";
    private HttpURLConnection httpConn;
    private String charset;
    private OutputStream outputStream;
    private PrintWriter writer;

    /**
     * This constructor initializes a new HTTP POST request with content type
     * is set to multipart/form-data
     *
     * @param requestURL
     * @param charset
     * @throws IOException
     */
    public MultipartUtility(String requestURL, String charset)
            throws IOException {
        this.charset = charset;

        // creates a unique boundary based on time stamp
        boundary = "===" + System.currentTimeMillis() + "===";

        URL url = new URL(requestURL);
        Log.e("URL", "URL : " + requestURL.toString());
        httpConn = (HttpURLConnection) url.openConnection();
        httpConn.setUseCaches(false);
        httpConn.setDoOutput(true); // indicates POST method
        httpConn.setDoInput(true);
        httpConn.setRequestProperty("Content-Type",
                "multipart/form-data; boundary=" + boundary);
        httpConn.setRequestProperty("User-Agent", "CodeJava Agent");
        httpConn.setRequestProperty("Test", "Bonjour");
        outputStream = httpConn.getOutputStream();
        writer = new PrintWriter(new OutputStreamWriter(outputStream, charset),
                true);
    }

    /**
     * Adds a form field to the request
     *
     * @param name  field name
     * @param value field value
     */
    public void addFormField(String name, String value) {
        writer.append("--" + boundary).append(LINE_FEED);
        writer.append("Content-Disposition: form-data; name=\"" + name + "\"")
                .append(LINE_FEED);
        writer.append("Content-Type: text/plain; charset=" + charset).append(
                LINE_FEED);
        writer.append(LINE_FEED);
        writer.append(value).append(LINE_FEED);
        writer.flush();
    }

    /**
     * Adds a upload file section to the request
     *
     * @param fieldName  name attribute in <input type="file" name="..." />
     * @param uploadFile a File to be uploaded
     * @throws IOException
     */
    public void addFilePart(String fieldName, File uploadFile)
            throws IOException {
        String fileName = uploadFile.getName();
        writer.append("--" + boundary).append(LINE_FEED);
        writer.append(
                "Content-Disposition: form-data; name=\"" + fieldName
                        + "\"; filename=\"" + fileName + "\"")
                .append(LINE_FEED);
        writer.append(
                "Content-Type: "
                        + URLConnection.guessContentTypeFromName(fileName))
                .append(LINE_FEED);
        writer.append("Content-Transfer-Encoding: binary").append(LINE_FEED);
        writer.append(LINE_FEED);
        writer.flush();

        FileInputStream inputStream = new FileInputStream(uploadFile);
        byte[] buffer = new byte[4096];
        int bytesRead = -1;
        while ((bytesRead = inputStream.read(buffer)) != -1) {
            outputStream.write(buffer, 0, bytesRead);
        }
        outputStream.flush();
        inputStream.close();

        writer.append(LINE_FEED);
        writer.flush();
    }

    /**
     * Adds a header field to the request.
     *
     * @param name  - name of the header field
     * @param value - value of the header field
     */
    public void addHeaderField(String name, String value) {
        writer.append(name + ": " + value).append(LINE_FEED);
        writer.flush();
    }

    /**
     * Completes the request and receives response from the server.
     *
     * @return a list of Strings as response in case the server returned
     * status OK, otherwise an exception is thrown.
     * @throws IOException
     */
    public String finish() throws IOException {
        StringBuffer response = new StringBuffer();

        writer.append(LINE_FEED).flush();
        writer.append("--" + boundary + "--").append(LINE_FEED);
        writer.close();

        // checks server's status code first
        int status = httpConn.getResponseCode();
        if (status == HttpURLConnection.HTTP_OK) {
            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    httpConn.getInputStream()));
            String line = null;
            while ((line = reader.readLine()) != null) {
                response.append(line);
            }
            reader.close();
            httpConn.disconnect();
        } else {
            throw new IOException("Server returned non-OK status: " + status);
        }

        return response.toString();
    }
}

A uploadusted filejunto con los parámetros.

NOTA: coloque este código a continuación en un subproceso que no sea ui para obtener respuesta.

String charset = "UTF-8";
String requestURL = "YOUR_URL";

MultipartUtility multipart = new MultipartUtility(requestURL, charset);
multipart.addFormField("param_name_1", "param_value");
multipart.addFormField("param_name_2", "param_value");
multipart.addFormField("param_name_3", "param_value");
multipart.addFilePart("file_param_1", new File(file_path));
String response = multipart.finish(); // response from server.

La solución de Jaydipsinh Zala no funcionó para mí, no sé por qué, pero parece estar cerca de la solución.

Así que fusionando este con la gran solución y explicación de Mihai Todor , el resultado es esta clase que actualmente funciona para mí. Si ayuda a alguien:

MultipartUtility2V.java

import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;
import java.nio.file.Files;

public class MultipartUtilityV2 {
    private HttpURLConnection httpConn;
    private DataOutputStream request;
    private final String boundary =  "*****";
    private final String crlf = "\r\n";
    private final String twoHyphens = "--";

    /**
     * This constructor initializes a new HTTP POST request with content type
     * is set to multipart/form-data
     *
     * @param requestURL
     * @throws IOException
     */
    public MultipartUtilityV2(String requestURL)
            throws IOException {

        // creates a unique boundary based on time stamp
        URL url = new URL(requestURL);
        httpConn = (HttpURLConnection) url.openConnection();
        httpConn.setUseCaches(false);
        httpConn.setDoOutput(true); // indicates POST method
        httpConn.setDoInput(true);

        httpConn.setRequestMethod("POST");
        httpConn.setRequestProperty("Connection", "Keep-Alive");
        httpConn.setRequestProperty("Cache-Control", "no-cache");
        httpConn.setRequestProperty(
                "Content-Type", "multipart/form-data;boundary=" + this.boundary);

        request =  new DataOutputStream(httpConn.getOutputStream());
    }

    /**
     * Adds a form field to the request
     *
     * @param name  field name
     * @param value field value
     */
    public void addFormField(String name, String value)throws IOException  {
        request.writeBytes(this.twoHyphens + this.boundary + this.crlf);
        request.writeBytes("Content-Disposition: form-data; name=\"" + name + "\""+ this.crlf);
        request.writeBytes("Content-Type: text/plain; charset=UTF-8" + this.crlf);
        request.writeBytes(this.crlf);
        request.writeBytes(value+ this.crlf);
        request.flush();
    }

    /**
     * Adds a upload file section to the request
     *
     * @param fieldName  name attribute in <input type="file" name="..." />
     * @param uploadFile a File to be uploaded
     * @throws IOException
     */
    public void addFilePart(String fieldName, File uploadFile)
            throws IOException {
        String fileName = uploadFile.getName();
        request.writeBytes(this.twoHyphens + this.boundary + this.crlf);
        request.writeBytes("Content-Disposition: form-data; name=\"" +
                fieldName + "\";filename=\"" +
                fileName + "\"" + this.crlf);
        request.writeBytes(this.crlf);

        byte[] bytes = Files.readAllBytes(uploadFile.toPath());
        request.write(bytes);
    }

    /**
     * Completes the request and receives response from the server.
     *
     * @return a list of Strings as response in case the server returned
     * status OK, otherwise an exception is thrown.
     * @throws IOException
     */
    public String finish() throws IOException {
        String response ="";

        request.writeBytes(this.crlf);
        request.writeBytes(this.twoHyphens + this.boundary +
                this.twoHyphens + this.crlf);

        request.flush();
        request.close();

        // checks server's status code first
        int status = httpConn.getResponseCode();
        if (status == HttpURLConnection.HTTP_OK) {
            InputStream responseStream = new
                    BufferedInputStream(httpConn.getInputStream());

            BufferedReader responseStreamReader =
                    new BufferedReader(new InputStreamReader(responseStream));

            String line = "";
            StringBuilder stringBuilder = new StringBuilder();

            while ((line = responseStreamReader.readLine()) != null) {
                stringBuilder.append(line).append("\n");
            }
            responseStreamReader.close();

            response = stringBuilder.toString();
            httpConn.disconnect();
        } else {
            throw new IOException("Server returned non-OK status: " + status);
        }

        return response;
    }
}

Esta respuesta https://stackoverflow.com/a/33149413/6481542 me consiguió el 90% del camino cargando archivos grandes en un servidor Django de desarrollo, pero tuve que usar setFixedLengthStreamingMode para que funcionara. Eso requiere establecer la longitud del contenido antes de escribir el contenido, lo que requiere una reescritura bastante significativa de la respuesta anterior. Aquí está mi resultado final

public class MultipartLargeUtility {
    private final String boundary;
    private static final String LINE_FEED = "\r\n";
    private HttpURLConnection httpConn;
    private String charset;
    private OutputStream outputStream;
    private PrintWriter writer;
    private final int maxBufferSize = 4096;
    private long contentLength = 0;
    private URL url;

    private List<FormField> fields;
    private List<FilePart> files;

    private class FormField {
        public String name;
        public String value;

        public FormField(String name, String value) {
            this.name = name;
            this.value = value;
        }
    }

    private class FilePart {
        public String fieldName;
        public File uploadFile;

        public FilePart(String fieldName, File uploadFile) {
            this.fieldName = fieldName;
            this.uploadFile = uploadFile;
        }
    }

    /**
     * This constructor initializes a new HTTP POST request with content type
     * is set to multipart/form-data
     *
     * @param requestURL
     * @param charset
     * @throws IOException
     */
    public MultipartLargeUtility(String requestURL, String charset, boolean requireCSRF)
            throws IOException {
        this.charset = charset;

        // creates a unique boundary based on time stamp
        boundary = "===" + System.currentTimeMillis() + "===";
        url = new URL(requestURL);
        fields = new ArrayList<>();
        files = new ArrayList<>();

        if (requireCSRF) {
            getCSRF();
        }
    }

    /**
     * Adds a form field to the request
     *
     * @param name  field name
     * @param value field value
     */
    public void addFormField(String name, String value)
            throws UnsupportedEncodingException {
        String fieldContent = "--" + boundary + LINE_FEED;
        fieldContent += "Content-Disposition: form-data; name=\"" + name + "\"" + LINE_FEED;
        fieldContent += "Content-Type: text/plain; charset=" + charset + LINE_FEED;
        fieldContent += LINE_FEED;
        fieldContent += value + LINE_FEED;
        contentLength += fieldContent.getBytes(charset).length;
        fields.add(new FormField(name, value));
    }

    /**
     * Adds a upload file section to the request
     *
     * @param fieldName  name attribute in <input type="file" name="..." />
     * @param uploadFile a File to be uploaded
     * @throws IOException
     */
    public void addFilePart(String fieldName, File uploadFile)
            throws IOException {
        String fileName = uploadFile.getName();

        String fieldContent = "--" + boundary + LINE_FEED;
        fieldContent += "Content-Disposition: form-data; name=\"" + fieldName
                + "\"; filename=\"" + fileName + "\"" + LINE_FEED;
        fieldContent += "Content-Type: "
                + URLConnection.guessContentTypeFromName(fileName) + LINE_FEED;
        fieldContent += "Content-Transfer-Encoding: binary" + LINE_FEED;
        fieldContent += LINE_FEED;
        // file content would go here
        fieldContent += LINE_FEED;
        contentLength += fieldContent.getBytes(charset).length;
        contentLength += uploadFile.length();
        files.add(new FilePart(fieldName, uploadFile));
    }

    /**
     * Adds a header field to the request.
     *
     * @param name  - name of the header field
     * @param value - value of the header field
     */
    //public void addHeaderField(String name, String value) {
    //    writer.append(name + ": " + value).append(LINE_FEED);
    //    writer.flush();
    //}

    /**
     * Completes the request and receives response from the server.
     *
     * @return a list of Strings as response in case the server returned
     * status OK, otherwise an exception is thrown.
     * @throws IOException
     */
    public List<String> finish() throws IOException {
        List<String> response = new ArrayList<String>();
        String content = "--" + boundary + "--" + LINE_FEED;
        contentLength += content.getBytes(charset).length;

        if (!openConnection()) {
            return response;
        }

        writeContent();

        // checks server's status code first
        int status = httpConn.getResponseCode();
        if (status == HttpURLConnection.HTTP_OK) {
            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    httpConn.getInputStream()));
            String line = null;
            while ((line = reader.readLine()) != null) {
                response.add(line);
            }
            reader.close();
            httpConn.disconnect();
        } else {
            throw new IOException("Server returned non-OK status: " + status);
        }
        return response;
    }

    private boolean getCSRF()
            throws IOException {
        /// First, need to get CSRF token from server
        /// Use GET request to get the token
        CookieManager cookieManager = new CookieManager();
        CookieHandler.setDefault(cookieManager);
        HttpURLConnection conn = null;

        conn = (HttpURLConnection) url.openConnection();

        conn.setUseCaches(false); // Don't use a Cached Copy
        conn.setRequestMethod("GET");
        conn.setRequestProperty("Connection", "Keep-Alive");
        conn.getContent();
        conn.disconnect();

        /// parse the returned object for the CSRF token
        CookieStore cookieJar = cookieManager.getCookieStore();
        List<HttpCookie> cookies = cookieJar.getCookies();
        String csrf = null;
        for (HttpCookie cookie : cookies) {
            Log.d("cookie", "" + cookie);
            if (cookie.getName().equals("csrftoken")) {
                csrf = cookie.getValue();
                break;
            }
        }
        if (csrf == null) {
            Log.d(TAG, "Unable to get CSRF");
            return false;
        }
        Log.d(TAG, "Received cookie: " + csrf);

        addFormField("csrfmiddlewaretoken", csrf);
        return true;
    }

    private boolean openConnection()
            throws IOException {
        httpConn = (HttpURLConnection) url.openConnection();
        httpConn.setUseCaches(false);
        httpConn.setDoOutput(true);    // indicates POST method
        httpConn.setDoInput(true);
        //httpConn.setRequestProperty("Accept-Encoding", "identity");
        httpConn.setFixedLengthStreamingMode(contentLength);
        httpConn.setRequestProperty("Connection", "Keep-Alive");
        httpConn.setRequestProperty("Content-Type",
                "multipart/form-data; boundary=" + boundary);
        outputStream = new BufferedOutputStream(httpConn.getOutputStream());
        writer = new PrintWriter(new OutputStreamWriter(outputStream, charset),
                true);
        return true;
    }

    private void writeContent()
            throws IOException {

        for (FormField field : fields) {
            writer.append("--" + boundary).append(LINE_FEED);
            writer.append("Content-Disposition: form-data; name=\"" + field.name + "\"")
                    .append(LINE_FEED);
            writer.append("Content-Type: text/plain; charset=" + charset).append(
                    LINE_FEED);
            writer.append(LINE_FEED);
            writer.append(field.value).append(LINE_FEED);
            writer.flush();
        }

        for (FilePart filePart : files) {
            String fileName = filePart.uploadFile.getName();
            writer.append("--" + boundary).append(LINE_FEED);
            writer.append(
                    "Content-Disposition: form-data; name=\"" + filePart.fieldName
                            + "\"; filename=\"" + fileName + "\"")
                    .append(LINE_FEED);
            writer.append(
                    "Content-Type: "
                            + URLConnection.guessContentTypeFromName(fileName))
                    .append(LINE_FEED);
            writer.append("Content-Transfer-Encoding: binary").append(LINE_FEED);
            writer.append(LINE_FEED);
            writer.flush();

            FileInputStream inputStream = new FileInputStream(filePart.uploadFile);
            int bufferSize = Math.min(inputStream.available(), maxBufferSize);
            byte[] buffer = new byte[bufferSize];
            int bytesRead = -1;
            while ((bytesRead = inputStream.read(buffer, 0, bufferSize)) != -1) {
                outputStream.write(buffer, 0, bytesRead);
            }
            outputStream.flush();
            inputStream.close();
            writer.append(LINE_FEED);
            writer.flush();
        }

        writer.append("--" + boundary + "--").append(LINE_FEED);
        writer.close();
    }
}

El uso es en gran medida el mismo que en la respuesta anterior, pero he incluido el soporte CSRF que Django usa de forma predeterminada con los formularios

boolean useCSRF = true;
MultipartLargeUtility multipart = new MultipartLargeUtility(url, "UTF-8",useCSRF);
multipart.addFormField("param1","value");
multipart.addFilePart("filefield",new File("/path/to/file"));
List<String> response = multipart.finish();
Log.w(TAG,"SERVER REPLIED:");
for(String line : response) {
    Log.w(TAG, "Upload Files Response:::" + line);
}

basado en la solución de Mihai, si alguien tiene el problema de guardar imágenes en el servidor como lo que sucedió en mi servidor. cambie el mapa de bits a la parte bytebuffer a:

ByteArrayOutputStream bos = new ByteArrayOutputStream();
        bitmap.compress(Bitmap.CompressFormat.JPEG,100,bos);
        byte[] pixels = bos.toByteArray();

No he probado esto, pero puedes intentar usar PipedInputStream y PipedOutputStream. Puede verse algo así como:

final Bitmap bmp = … // your bitmap

// Set up Piped streams
final PipedOutputStream pos = new PipedOutputStream(new ByteArrayOutputStream());
final PipedInputStream pis = new PipedInputStream(pos);

// Send bitmap data to the PipedOutputStream in a separate thread
new Thread() {
    public void run() {
        bmp.compress(Bitmap.CompressFormat.PNG, 100, pos);
    }
}.start();

// Send POST request
try {
    // Construct InputStreamEntity that feeds off of the PipedInputStream
    InputStreamEntity reqEntity = new InputStreamEntity(pis, -1);

    HttpClient httpclient = new DefaultHttpClient();
    HttpPost httppost = new HttpPost(url);
    reqEntity.setContentType("binary/octet-stream");
    reqEntity.setChunked(true);
    httppost.setEntity(reqEntity);
    HttpResponse response = httpclient.execute(httppost);
} catch (Exception e) {
    e.printStackTrace()
}

Esto es lo que hice para subir fotos usando la solicitud de publicación.

public void uploadFile(int directoryID, String filePath) {
    Bitmap bitmapOrg = BitmapFactory.decodeFile(filePath);
    ByteArrayOutputStream bao = new ByteArrayOutputStream();

    String upload_url = BASE_URL + UPLOAD_FILE;
    bitmapOrg.compress(Bitmap.CompressFormat.JPEG, 90, bao);

    byte[] data = bao.toByteArray();

    HttpClient httpClient = new DefaultHttpClient();
    HttpPost postRequest = new HttpPost(upload_url);
    MultipartEntity entity = new MultipartEntity(HttpMultipartMode.BROWSER_COMPATIBLE);

    try {
        // Set Data and Content-type header for the image
        FileBody fb = new FileBody(new File(filePath), "image/jpeg");
        StringBody contentString = new StringBody(directoryID + "");

        entity.addPart("file", fb);
        entity.addPart("directory_id", contentString);
        postRequest.setEntity(entity);

        HttpResponse response = httpClient.execute(postRequest);
        // Read the response
        String jsonString = EntityUtils.toString(response.getEntity());
        Log.e("response after uploading file ", jsonString);

    } catch (Exception e) {
        Log.e("Error in uploadFile", e.getMessage());
    }
}

NOTA: Este código requiere bibliotecas, así que siga las instrucciones aquí para obtener las bibliotecas.

Encontré el uso de okHttp mucho más fácil ya que no pude lograr que ninguna de estas soluciones funcionara: https://stackoverflow.com/a/37942387/447549

Probé las soluciones anteriores y ninguna funcionó para mí fuera de la caja.

Sin embargo, http://www.baeldung.com/httpclient-post-http-request . La línea 6 POST Multipart Request funcionó en segundos

public void whenSendMultipartRequestUsingHttpClient_thenCorrect() 
  throws ClientProtocolException, IOException {
    CloseableHttpClient client = HttpClients.createDefault();
    HttpPost httpPost = new HttpPost("http://www.example.com");

    MultipartEntityBuilder builder = MultipartEntityBuilder.create();
    builder.addTextBody("username", "John");
    builder.addTextBody("password", "pass");
    builder.addBinaryBody("file", new File("test.txt"),
      ContentType.APPLICATION_OCTET_STREAM, "file.ext");

    HttpEntity multipart = builder.build();
    httpPost.setEntity(multipart);

    CloseableHttpResponse response = client.execute(httpPost);
    client.close();
}