Uploading image multi part form from android

Question

i have this problem that i want to upload image on a server through multi-part form but its keep giving me invalid image when i try to upload it from android but work fine from web. this is html form which work fine.

http://letitripple.org/htmlForm.html

this is the request this html form create. (i get from chrome developer tool)

------WebKitFormBoundaryPug6xAUAlaUPbR86 Content-Disposition: form-data; name="wp-user-avatars"; filename="Desert.jpg" Content-Type: image/jpeg

------WebKitFormBoundaryPug6xAUAlaUPbR86 Content-Disposition: form-data; name="login_id"

51 ------WebKitFormBoundaryPug6xAUAlaUPbR86 Content-Disposition: form-data; name="cookie"

[email protected]|1473394633|vcN3CTbKi6pkAjPMKH1D9MHucPLKhw3wyeS7ViSTgGb|f5cbd913f6c3d6940066a660bac5908adb016682ce34f48e8200773eb4503c1e ------WebKitFormBoundaryPug6xAUAlaUPbR86 Content-Disposition: form-data; name="submit"

submit ------WebKitFormBoundaryPug6xAUAlaUPbR86--

This is my android code which is not working.

 public AppResponse uploadImageFile(String csURL, String csFilePath)
{
    AppResponse appResponse = null;

    HttpURLConnection conn = null;
    DataOutputStream dos = null;
    ByteArrayOutputStream output = null;
    InputStream inStream = null;


    String Url = csURL;
    String existingFileName = csFilePath;


    String lineEnd = "\r\n";
    String twoHyphens = "--";
    String boundary = "WebKitFormBoundaryleA9RIQsQBxW8Cgl";
    int bytesRead, bytesAvailable, bufferSize;
    byte[] buffer;
 //   String reponse_data = null;
    int maxBufferSize = 1 * 1024 * 1024;
  //  String urlString = "YOUR PHP LINK FOR UPLOADING IMAGE";
    try {
        //------------------ CLIENT REQUEST
        // FileInputStream fileInputStream = new FileInputStream(new File(existingFileName) );
        // open a URL connection to the Servlet
        URL url = new URL(Url);
        // Open a HTTP connection to the URL
        conn = (HttpURLConnection) url.openConnection();
        // Allow Inputs
        conn.setDoInput(true);
        // Allow Outputs
        conn.setDoOutput(true);
        // Don't use a cached copy.
        conn.setUseCaches(false);

        FileInputStream fileInputStream = new FileInputStream(new File(existingFileName));//You can get an inputStream using any IO API
        byte[] bytes;
        byte[] buffers = new byte[605244];
        int bytesReads;
        output = new ByteArrayOutputStream();


        // Use a post method.
        conn.setRequestMethod("POST");
        conn.setRequestProperty("Connection", "Keep-Alive");

        conn.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + twoHyphens + twoHyphens + boundary);
        //conn.setRequestProperty("attach1", existingFileName);
        dos = new DataOutputStream(conn.getOutputStream());
        dos.writeBytes(twoHyphens + twoHyphens + twoHyphens + boundary + "\r\n");



        dos.writeBytes("Content-Disposition: form-data; name=\"attach1\"; filename=\"profile.jpg\"\n Content-Type: image/jpg\r\n\r\n\r\n"); // uploaded_file_name is the Name of the File to be uploaded

        // create a buffer of  maximum size
        bytesAvailable = fileInputStream.available();

        bufferSize = Math.min(bytesAvailable, maxBufferSize);
        buffer = new byte[bufferSize];

        // read file and write it into form...
        bytesRead = fileInputStream.read(buffer, 0, bufferSize);

        while (bytesRead > 0) {

            dos.write(buffer, 0, bufferSize);
            bytesAvailable = fileInputStream.available();
            bufferSize = Math.min(bytesAvailable, maxBufferSize);
            bytesRead = fileInputStream.read(buffer, 0, bufferSize);
            Log.e("Value", "Writing");

        }

        // send multipart form data necesssary after file data...
        dos.writeBytes(lineEnd);

        dos.writeBytes(twoHyphens + twoHyphens + twoHyphens + boundary + twoHyphens);

        //String strInput = dos.toString();

        int responseCode = conn.getResponseCode();

        String serverResponseMessage = conn.getResponseMessage();


        fileInputStream.close();

        dos.flush();
        dos.close();

        int nResponseCode = conn.getResponseCode();
        inStream = new DataInputStream(conn.getInputStream());

        BufferedReader in = new BufferedReader(new InputStreamReader(inStream));

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

        while ((line = in.readLine()) != null) {
            Log.e("Debug", "Server Response " + csResult);
            csResult.append(line);
        }


        appResponse = new AppResponse(nResponseCode, csResult.toString());



    }
    catch (IOException ioe) {
        Log.e("Debug", "error: " + ioe.getMessage(), ioe);
    }


    return appResponse;
}

Answer 1

We build the utility class called MultipartUtility with the following code:

import java.io.BufferedReader;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.List;

/**
 * This utility class provides an abstraction layer for sending multipart HTTP
 * POST requests to a web server.
 * @author www.codejava.net
 *
 */
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);
        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 List<String> finish() throws IOException {
        List<String> response = new ArrayList<String>();

        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.add(line);
            }
            reader.close();
            httpConn.disconnect();
        } else {
            throw new IOException("Server returned non-OK status: " + status);
        }

        return response;
    }
}

This utility class uses java.net.HttpURLConnection class and follows the RFC 1867 (Form-based File Upload in HTML) to make an HTTP POST request with multipart/form-data content type in order to upload files to a given URL. It has one constructor and three methods:

1. MultipartUtility(String requestURL, String charset): creates a new instance of this class for a given request URL and charset.
2. void addFormField(String name, String value): adds a regular text field to the request.
3. void addHeaderField(String name, String value): adds an HTTP header field to the request.
4. void addFilePart(String fieldName, File uploadFile): attach a file to be uploaded to the request.
5. List finish(): this method must be invoked lastly to complete the request and receive response from server as a list of String.

Since the MultipartUtility class abstracts all the detailed implementation, a usage example would be pretty simple as shown in the following program:

import java.io.File;
import java.io.IOException;
import java.util.List;

/**
 * This program demonstrates a usage of the MultipartUtility class.
 * @author www.codejava.net
 *
 */
public class MultipartFileUploader {

    public static void main(String[] args) {
        String charset = "UTF-8";
        File uploadFile1 = new File("e:/Test/PIC1.JPG");
        File uploadFile2 = new File("e:/Test/PIC2.JPG");
        String requestURL = "http://localhost:8080/FileUploadSpringMVC/uploadFile.do";

        try {
            MultipartUtility multipart = new MultipartUtility(requestURL, charset);

            multipart.addHeaderField("User-Agent", "CodeJava");
            multipart.addHeaderField("Test-Header", "Header-Value");

            multipart.addFormField("description", "Cool Pictures");
            multipart.addFormField("keywords", "Java,upload,Spring");

            multipart.addFilePart("fileUpload", uploadFile1);
            multipart.addFilePart("fileUpload", uploadFile2);

            List<String> response = multipart.finish();

            System.out.println("SERVER REPLIED:");

            for (String line : response) {
                System.out.println(line);
            }
        } catch (IOException ex) {
            System.err.println(ex);
        }
    }
}