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Image file is corrupted after uploading using servlet [duplicate]

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Recommended way to save uploaded files in a servlet application
(2 answers)
Closed 1 year ago.
I am try uploading the image using the below servlet
But after upload I am able save the file but I am not able to open I checked the file is corrupted.
Instead of using the annotation I have describe multipart-config in web.xml.
I this code I am trying to get the image file I send the data using AJAX.
Then I am redirected to Register servlet there I am using InputStream class to handle data.
After this I creating the file and upload this Inputdata to file in some directory on server.
public class Register extends HttpServlet{
#Override
protected void doPost(HttpServletRequest req,HttpServletResponse res) throws ServletException,IOException{
String username=req.getParameter("username");
String password=req.getParameter("password");
String email=req.getParameter("email");
Part part = req.getPart("image");
String filename = part.getSubmittedFileName();
InputStream is = req.getInputStream();
byte[] data = new byte[is.available()];
String path = "D:\\FullstackWeb\\images\\icon\\"+filename;
System.out.println(path);
FileOutputStream fos=new FileOutputStream(path);
fos.write(data);
res.setContentType("text/html");
PrintWriter out = res.getWriter();
try {
Class.forName("com.mysql.jdbc.Driver");
Connection conn = DriverManager.getConnection("jdbc:mysql://dns1.nishchay.com:3306/register","demouser","123Nbr#");
String query = "Insert INTO register.signup(username,email,userpassword,filename) values(? ,?, ?,?)";
PreparedStatement pstmt= conn.prepareStatement(query);
pstmt.setString(1, username);
pstmt.setString(2, email);
pstmt.setString(3, password);
pstmt.setString(4, path);
pstmt.executeUpdate();
conn.close();
}catch(Exception e) {
out.println("<h1>Issue is occured</h1>");
}
}
}```

You are not reading in the image data:
InputStream is = req.getInputStream();
byte[] data = new byte[is.available()];
String path = "D:\\FullstackWeb\\images\\icon\\"+filename;
System.out.println(path);
FileOutputStream fos=new FileOutputStream(path);
fos.write(data);
does not contain any is.read() call and it doesn't close the FileOutputStream.
In addition to that your allocated buffer is to small for most images. The JavaDoc for InputStream.available() states
Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking
To completely read the image data you could simply replace the above code with
Files.copy(is, Paths.get("D:\\FullstackWeb\\images\\icon\\"+filename));
but with a big caveat: since the file name is supplied by the user of your service this opens your code to security problems.

Socket closed error when trying to socket write (bytearray)

The code below triggers the following error:
Error: Exception when sending command: Socket closed
public synchronized void sendCommand(final ServerCommand pServerCommand) {
if (pServerCommand == null) {
return;
}
try {
//byte array to write server command
ByteArrayOutputStream baosData = new ByteArrayOutputStream();
DataOutputStream osData = new DataOutputStream(baosData);
//byte array that will be used to write on socket
//this will contain length of ByteArrayData and then ByteArrayData
ByteArrayOutputStream baosOut = new ByteArrayOutputStream();
DataOutputStream osOut = new DataOutputStream(baosOut);
//write command into osData byte array
pServerCommand.write(osData);
//write length of command into main byte array
osOut.writeShort(baosData.size());
//write command into main byte array
baosData.writeTo(baosOut);
OutputStream out = this.getSocket()
.getOutputStream();
//write main byte array on socket
byte[] data = baosOut.toByteArray();
out.write(data, 0, data.length);
out.flush();
} catch (IOException e) {
Log.pt("Exception when sending command", e.getMessage());
// Socket is possibly closed
}
}

For whatever reason, the socket to which you are writing is closed. Either it was not opened, it was closed already on your end, or it was closed on the other end, apparently a server.
A couple of suggestions. First, move all the data prep code to a method that returns a byte[]. Socket code is hard enough without mixing it with code that manipulates data.
Second, make sure the socket was actually opened. That's not a given.

Golang: dealing with binary data

I have application client(javascript)-server(golang) and the connection between them are all over websocket. I'm planing using binary messages and i want to create my own protocol for messaging like in this page protocol.
I'm already figure it out in javascript by using DataView but not in golang. Event the primitive data type are similar like they have int8, uint8, int16, uint16 etc, i can't figure it out.
This is the message frame:
1 Uint8 opcode
2 Uint16 msg
This is the example of javascript code handling the incoming message form websocket with message frame above:
websocket.onmessage = function(evt) {
var data = new DataView(evt.data);
var opcode = data.getUint8(0);
var msg = data.getUint16(1);
}
Can you show me how to do it in golang? i'm using gorilla websocket. I know that read message are in []byte, but i don't know how to slice it like javascript does with DataView.
Thanks

For the uint16 you'll need the binary package. Double-check if LittleEndian is what you want.
package main
import (
"encoding/binary"
)
func main() {
a := []byte("yak")
/* opcode */ _ = uint8(a[0])
/* message */ _ = binary.LittleEndian.Uint16(a[1:3])
}
https://play.golang.org/p/HRu7C5h2a5

Send Base64 encoded image as string to Chromecast

The problem is to send local image from phone as encoded Base64 string to Chromecast. And decode it using my Custom Receiver. I was following this guide which is based on this project sample.
I suggest the problem might be in:
Custom Receiver is not proper (I'm not strong in JS).
Chromecast didn't load that Receiver (I don't know how to check that).
Image was encoded wrong on device or decoded on Chromecast.
You see, it seems like I coded everithing right since the status of Chromecast when I send photo is:
statusCode 0 (success),
application name: Default Media Receiver,
status: Ready To Cast,
sessionId: 34D6CE75-4798-4294-BF45-2F4701CE4782,
wasLaunched: true.
This is how I send image as String:
mCastManager.castImage(mCastManager.getEncodedImage(currentEntryPictureByPoint.getPath()));
Methods used:
public void castImage(String encodedImage)
{
Log.d(TAG, "castImage()");
String image_string = createJsonMessage(MessageType.image, encodedImage);
sendMessage(image_string);
}
private static String createJsonMessage(MessageType type, String message)
{
return String.format("{\"type\":\"%s\", \"data\":\"%s\"}", type.toString(), message);
}
/**
* Convert Image to encoded String
* */
public String getEncodedImage(String path){
Bitmap bm = BitmapFactory.decodeFile(path);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bm.compress(Bitmap.CompressFormat.JPEG, 100, baos); //bm is the bitmap object
byte[] byteArrayImage = baos.toByteArray();
String encodedImage = Base64.encodeToString(byteArrayImage, Base64.DEFAULT);
return encodedImage;
}
/**
* Send a text message to the receiver
*
* #param message
*/
private void sendMessage(String message) {
if (mApiClient != null && mCustomImageChannel != null) {
try {
Cast.CastApi.sendMessage(mApiClient,
mCustomImageChannel.getNamespace(), message)
.setResultCallback(new ResultCallback<Status>() {
#Override
public void onResult(Status result) {
if (!result.isSuccess()) {
//ALWAYS REACHING HERE :(
Log.e(TAG, "Sending message failed");
}
}
});
} catch (Exception e) {
Log.e(TAG, "Exception while sending message", e);
}
} else {
Toast.makeText(mContext, message, Toast.LENGTH_SHORT)
.show();
}
}
If the sending process is correct then the Receiver is wrong and don't know how to decode this message properly.
The way I uploaded it (well, at least I think that its uploaded...)
Registered new Custom Receiver on Google Cast Console and received Application ID.
Created cast_receiver.js file. The code inside this file is supposed to decode Base64 string into image.
Copied the code for Receiver from guide to .js file and changed NAMESPACE inside to my one: urn:x-cast:com.it.innovations.smartbus
Uploaded file on Google Drive and modified its access visibility to full public
Copied the link to file to URL field in Cast Console. This link is direct download of file.
Restarted Chromecast. Seems like it tried to download something but not sure if succeed
If anyone faced this problem, please point me out what I am doing wrong. Appreciate any help.
P.S. tell if some more code needed...

I very strongly suggest to avoid using the sendMessage() for sending any large data set; those channels are meant to be used as control channels and not as a way to send a chunk of data. A much much simpler and more robust approach is to embed a tiny dumb web server in your local app (on the sender side) and "serve" your images to your chromecast. There is a number of ready-to-use embedded web servers that you can put in your app and requires almost no configuration; then you can serve all sorts of media, including images, to your chromecast with even the default or styled receiver.

Extending Selenium RC with new methods

I am extending the selenium RC by using user-extension.js.
It is able to call the new method function, but throwing following error message.
*ERROR: Command execution failure. Please search the forum at http://clearspace.openqa.org for error details from the log window.
The error message is: Object doesn't support this property or
method*
As this program is executed on Google.com, any one can copy the sample code and execute on their respective PCs.
package package1;
import static org.testng.AssertJUnit.*;
import org.testng.annotations.*;
import com.thoughtworks.selenium.*;
public class Sample2
{
private static final String Timeout = "30000";
private static final String BASE_URL = "http://google.com/";
private static final String BASE_URL_1 = "/";
private Selenium selenium;
private HttpCommandProcessor proc;
#BeforeClass
protected void setUp()throws Exception
{
proc = new HttpCommandProcessor("localhost", 4444, "*iexplore", BASE_URL);
selenium = new DefaultSelenium(proc);
selenium.start();
selenium.windowFocus();
selenium.windowMaximize();
selenium.windowFocus();
}
#AfterClass(alwaysRun=true)
protected void tearDown() throws Exception
{
selenium.stop();
}
#Test(groups="search")
public void test_GoogleSearch() throws Exception
{
selenium.open(BASE_URL_1);
selenium.type("name=q", "Bharath Marrivada");
//selenium.click("btnG");
proc.doCommand("myMethod",new String[] {"btnG"}); //user extension
Thread.sleep(5000);
}
}
user-extension.js
Selenium.prototype.doMyMethod = function(inputParams)
{
this.browserbot.click("btnG");
return null;
};
.js and Selenium JAR are in the same folder and executing the Selenium JAR using following command.
java -jar selenium-server.jar -userExtensions user-extensions.js
Any help on this issue?

It means that your command in user-extension file is not locating the element. Try running that in the IDE and check if it works fine

It works for me. Here is the modified user-extensions.js file code:
Selenium.prototype.doMyMethod = function(locator) {
var element = this.page().findElement(locator);
element.click();
};
Rest all remains the same. Hope this helps!!!