Develop Reference

Sending a photo from a device using Python3 and receiving it on an Android Device via TCP gives an OOM on the Android Device

I am trying to send a photo from my Raspberry Pi using Python 3, to my Android Device. I am doing this over TCP with the Pi as the Client, and the Android Device as my Server. My goal is to send a photo file from Pi to my Android Device. My Android Device would then decode that photo data and then set it as the drawable for an ImageView in my App. Kindly note that I'm sending a 200kB image that's 640x480.
I have tried a set up where the Pi sends text to my Android Device via TCP, and I've had success with that.
What I did next was to attempt to send a photo from a Python3 client to a Python3 Server. In this case, I used the Pi still as my client, and I used my MacOS Laptop as the Server. This are the code that I ended up using.
Server - MAC OS
import socket # Import socket module
s = socket.socket() # Create a socket object
host = socket.gethostname() # Get local machine name
port = 11111 # Reserve a port for your service.
s.bind((host, port)) # Bind to the port
f = open('torecv.jpg','wb')
s.listen(5) # Now wait for client connection.
while True:
c, addr = s.accept() # Establish connection with client.
print('Got connection from', addr)
print("Receiving...")
l = c.recv(1024)
while (l):
print("Receiving...")
f.write(l)
l = c.recv(1024)
f.close()
print("Done Receiving")
c.send(b'Thank you for connecting')
c.shutdown(socket.SHUT_RDWR)
c.close() # Close the connection
Client - Pi
import socket # Import socket module
import os
s = socket.socket() # Create a socket object
host = socket.gethostname() # Get local machine name
host = '192.168.254.194' # Get local machine name
port = 6001 # Reserve a port for your service.
CWD_PATH = os.getcwd()
PATH_TO_IMG_DIR = os.path.join(CWD_PATH, 'img_folder', 'test.jpg')
s.connect((host, port))
#s.send(b'Hello Server!')
f = open(PATH_TO_IMG_DIR,'rb')
print('Sending...')
l = f.read(1024)
while (l):
print('Sending...')
s.send(l)
l = f.read(1024)
f.close()
print("Done Sending")
s.shutdown(socket.SHUT_WR)
print(s.recv(1024))
s.close # Close the socket when done
Using this code, I was able to transfer the photo from my Pi to my MacOS laptop.
Now, I used the code here as reference in order to transfer my photo from my Pi to my Android Device. Now, this is my code:
Server - Android
class ServerThread implements Runnable {
public void run() {
Socket socket;
try {
Log.e(TAG, "starting the serverthread at port 6001");
serverSocket = new ServerSocket(6001);
} catch (IOException e) {
Log.e(TAG, "exception in creating server socket: ", e);
e.printStackTrace();
}
while (!Thread.currentThread().isInterrupted()) {
try {
socket = serverSocket.accept();
CommunicationThread commThread = new CommunicationThread(socket);
new Thread(commThread).start();
} catch (IOException e) {
}
}
}
}
class CommunicationThread implements Runnable{
private Socket clientSocket;
private DataInputStream input;//private BufferedReader input;
public CommunicationThread(Socket clientSocket) {
this.clientSocket = clientSocket;
try {
Log.e(TAG, "getting data from the input stream!");
//this.input = new BufferedReader(new InputStreamReader(this.clientSocket.getInputStream()));
InputStream in = this.clientSocket.getInputStream();
this.input = new DataInputStream(in);
} catch (IOException e) {
Log.e(TAG, "error in creating data input stream: ", e);
e.printStackTrace();
}
}
public void run() {
Log.e(TAG, "running the code!");
while (!Thread.currentThread().isInterrupted()) {
try {
Log.e(TAG, "parsing the input data stream!");
byte[] data;//String read = input.readLine();
int len= this.input.readInt();
if (len > 0) {
data = new byte[len];
this.input.readFully(data,0,data.length);
}
/*
ByteArrayOutputStream out = new ByteArrayOutputStream();
byte[] data;
int length = 0;
while ((length = this.input.read(data))!=-1) {
out.write(data,0,length);
}
data=out.toByteArray();
*/
Log.e(TAG, "Updating the UI through a thread!!");
// updateConversationHandler.post(new updateUIThread(data));
} catch (IOException e) {
// TODO Auto-generated catch block
Log.e(TAG, "error in reading sent data! ", e);
e.printStackTrace();
}
}
}
}
And in order to use these classes, I had declared the following as global variables:
Thread serverThread = null;
Handler updateConversationHandler;
And in my onCreate(), I have the following:
updateConversationHandler = new Handler();
this.serverThread = new Thread(new ServerThread());
this.serverThread.start();
The app would start, and the socket would be opened. However, when I attempt to send in the photo from my Pi, I hit an error at this block of code:
public void run() {
Log.e(TAG, "running the code!");
while (!Thread.currentThread().isInterrupted()) {
try {
Log.e(TAG, "parsing the input data stream!");
byte[] data;//String read = input.readLine();
int len= this.input.readInt();
if (len > 0) {
data = new byte[len];
this.input.readFully(data,0,data.length);
}
/*
ByteArrayOutputStream out = new ByteArrayOutputStream();
byte[] data;
int length = 0;
while ((length = this.input.read(data))!=-1) {
out.write(data,0,length);
}
data=out.toByteArray();
*/
Log.e(TAG, "Updating the UI through a thread!!");
// updateConversationHandler.post(new updateUIThread(data));
} catch (IOException e) {
// TODO Auto-generated catch block
Log.e(TAG, "error in reading sent data! ", e);
e.printStackTrace();
}
}
}
class updateUIThread implements Runnable {
private byte[] byteArray;//private String msg;
public updateUIThread(byte[] array){ //public updateUIThread(String str) {
this.byteArray=array; //this.msg = str;
}
#Override
public void run() {
Log.e(TAG, "running the photo update!");
Bitmap bitmap = BitmapFactory.decodeByteArray(byteArray , 0, byteArray .length);
ivBed.setImageBitmap(bitmap);//text.setText(text.getText().toString()+"Client Says: "+ msg + "\n");
}
}
Originally, the line:
data = new byte[len];
was outside the if(len>0) condition. But what happened was, for some reason, the Pi sent in a negative value, and of course we don't want a negative value for the len variable. Of course, I hit an error when I tried to create the byte array data with a negative length. I then put that line in the if condition.
However, after I did, I hit on OOM Error in the same line data = new byte[len];
Process: agict.work.freelance.patientsensor, PID: 15224
java.lang.OutOfMemoryError: Failed to allocate a 1677608328 byte allocation with 6291456 free bytes and 254MB until OOM, max allowed footprint 7797480, growth limit 268435456
I have a hunch that in the 2nd error, I was trying to initialize the byte array with a value that was actually the image data already, hence, the OOM error.
However, if I just take in the first value and assign it as the len, there's a chance that I'd get a negative number and the code would hit the first error.
Would there be a chance that I have to tweak something in order to transfer a photo data from Python3 to Android? I have a feeling that there's a format mismatch of sorts that's happening.
Again, my goal is to send a photo file from Python3 to my Android Device via TCP. The Python3 will be given a file, and the Android Device will decode the input it gets, and once decoded, use that data as the drawable for an ImageView.

According to me that error is caused by the size of the bitmap that you are trying to set for the ImageView. Checking sizes before use and/or scaling the bitmap may solve the issue. I've encountered such problems in the past before I start using third party libraries to load images.
You can take a look at this article from Android Developers and I think it can help:
https://developer.android.com/topic/performance/graphics/load-bitmap#java

I got it. You're supposed to use a ByteArrayOutputStream Object.
class ServerImageThread implements Runnable{
ServerSocket ss;
Socket s;
DataInputStream dis;
byte[] data;
#Override
public void run(){
try{
ss = new ServerSocket(6001);
while(true){
s = ss.accept();
InputStream in = s.getInputStream();
dis = new DataInputStream(in);
// read from the stream
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] content = new byte[1024];
int bytesRead = -1;
while( (bytesRead = in.read(content)) != -1 ) {
baos.write( content, 0, bytesRead );
} // while
Log.e(TAG, "made it through!");
Log.e(TAG, "baos size is = " + baos.size());
File file = new File(
Environment.getExternalStorageDirectory(), "test.jpg");
FileOutputStream fos = null;
try {
fos = new FileOutputStream(file);
baos.writeTo(fos);
Log.e(TAG, "managed to write baos to fos");
} catch(IOException ioe) {
// Handle exception here
Log.e(TAG, "baos IOException = ", ioe);
ioe.printStackTrace();
} finally {
Log.e(TAG, "closing fos");
fos.close();
}
}
}
catch(IOException e) {
Log.e(TAG, "exception in creating server socket: ", e);
e.printStackTrace();
}
}
}
You can call this via:
Thread myThread = new Thread(new ServerImageThread());
myThread.start();

Writing a bluetooth input stream to a file skips data

I am trying to write an app that will log the output of an arduino Due to a text file on the phone or tablet. The output rate is 1kHz. I have based my app on the Blueserial code (https://github.com/plastygrove/BlueSerial). The bluetooth connection gets established properly with the arduino bluetooth module, the commands are sent and received properly and everything seems to work just fine. However, the file that I am saving the data to is missing blocks of data, usually around 200ms worth every so often (I have a millisecond timestamp included in my data), resulting in corrupted data. I have been trying to figure out the source of the problem and I think it might be related to the gc but at this point I am at a loss. This is the code that writes my data to the file:
private class ReadInput implements Runnable {
private boolean bStop = false;
private Thread t;
public ReadInput() {
t = new Thread(this, "Input Thread");
t.start();
}
public boolean isRunning() {
return t.isAlive();
}
public void run() {
InputStream inputStream;
try {
inputStream = mBTSocket.getInputStream();
BufferedInputStream bis = new BufferedInputStream(inputStream);
while (!bStop) {
byte[] buffer = new byte[250];
int bytes = 0;
if (bis.available() > 0) {
bytes = bis.read(buffer);
strInput = new String(buffer, 0, bytes);
sb.append(strInput);
int endOfLineIndex = sb.indexOf("\r\n"); // determine the end-of-line
pw.print(strInput); // print buffer to the file buffer
pw.flush(); // flush buffer and force write to media
if (endOfLineIndex > 0) { // if end-of-line,
String sbprint = sb.substring(0, endOfLineIndex); // extract string
sb.delete(0, sb.length()); // and clear the string
pw.print(strInput); // write buffer to file buffer
pw.flush(); // force writing to file
pw.close(); // close print writer
try {
f.close(); // close file output stream
} catch (IOException e) {
e.printStackTrace();
}
}
sb.delete(0, sb.length()); strInput = "";
}
//Thread.sleep(100);
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void stop() {
bStop = true;
}
}
and this is my file outputsteam and printwriter declarations:
String strInput = null;
static PrintWriter pw = null;
static FileOutputStream f = null;
private StringBuilder sb = new StringBuilder();
The data I am sending is formatted as so:
24.330,-58,5,119,460\n
24.331,-86,25,-105,460\n
24.332,66,41,-145,460\n
24.333,90,-23,-85,4622,-7,119,460\n
24.524,6,-95,107,461\n
24.525,10,-7,-173,461\n
24.526,-22,33,103,461\n
and in this example you can see where it skipped some data. Thank you for helping out!

There appears to be code missing or you have some extra logic.
For example the StringBuilder doesn't appear to be doing anything,
bStop is never set/cleared. But you are always printing out the incoming data
via strInput.
The end of line handling also looks off, specifically this:
String sbprint = sb.substring(0, endOfLineIndex); // extract string
sb.delete(0, sb.length());
You extract the string and then delete the whole buffer sb.delete(0,sb.length())
same at the bottom of the loop.

Unexpected status line: ICY 200 OK for URL openStream() method?

According to changes for kitakt 4.4 there were some problems with playing shoutcast streams (those returning "ICY" instead of "HTTP/1.x" response).
So solution for kitkat was to reregister "icy" protocol prefix in JVM once before we opened a stream by this:
try {
java.net.URL.setURLStreamHandlerFactory( new java.net.URLStreamHandlerFactory(){
public java.net.URLStreamHandler createURLStreamHandler( String protocol ) {
Log.d( LOG, "Asking for stream handler for protocol: '" + protocol + "'" );
if ("icy".equals( protocol )) return new com.spoledge.aacdecoder.IcyURLStreamHandler();
return null;
}
});
}
catch (Throwable t) {
Log.w( LOG, "Cannot set the ICY URLStreamHandler - maybe already set ? - " + t );
}
I have problem with open audio stream to make it register. After I call url.opnestream(stream) I got exception:
java.net.ProtocolException: Unexpected status line: ICY 200 OK
How could I fix it?
Here is sample of registering audio, so far what I did..
try {
URL url = null;
url = new URL(u);
inputStream = url.openStream();
startTime = System.currentTimeMillis();
Boolean isSDPresent = android.os.Environment.getExternalStorageState().equals(android.os.Environment.MEDIA_MOUNTED);
String fileName = File.separator + "radio_" + "recording_" + channelMetadata.replaceAll("\\W", "") + System.currentTimeMillis();
if(isSDPresent)
{
outputSource = Environment.getExternalStorageDirectory() + fileName;
}
else
{
outputSource = Environment.getDataDirectory() + fileName;
}
if(contentType.equals("audio/aacp"))
fileOutputStream = new FileOutputStream(outputSource + ".acc");
else if(contentType.equals("audio/mpeg"))
fileOutputStream = new FileOutputStream(outputSource + ".mp3");
else
fileOutputStream = new FileOutputStream(outputSource + ".nieznany_format");
int bytesRead = 0;
int bytes;
while (((bytes = inputStream.read()) != -1) && isRecording) {
fileOutputStream.write(bytes);
bytesRead++;
stopTime = System.currentTimeMillis();
long seconds = (Math.abs(startTime-stopTime));
int minutes = 1000 * 60 * 60;
if(minutes<=seconds)
{
Log.d("xxx", "recording task exceed stopped");
break;
}
}
inputStream.close();
fileOutputStream.close();
} catch (IOException e) {
e.printStackTrace();
isRecording = false;
}
isRecording = false;
return null;

Various changes were made for Android 4.4, and it seems that the non-standard ShoutCast ICY header is not supported by Android.
It seems though that the good people of OkHttp fixed the issue (issue 1 and issue 2) already a few days ago.
What you can do, is simply use OkHttp lib directly in your application and by that you'll use the newer OkHttp version (the one with the fix) and not the one shipped with Android (where you'll have to wait for an OS update).
This will also fix it for your application running on other devices that might suffer from that issue.

The answer of Assaf Gamliel worked for me. For those not familiar with this, you have to download the last .jar from okHttp and the .jar from the dependency okio . Add them to your libs directory and connect like this :
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
.url(mediaUrl)
.build();
Response response = client.newCall(request).execute();
InputStream stream = response.body().byteStream();

The easiest fix ever.
which is 100% working for me,
for shoutcast , change your URL ex. "http://192.168.1.1:9292" to "icy://192.168.1.1:9292"
and you'll be fine.

Error to send data to tablet through bluetooth device

I'm facing the following problem:
I am connecting two devices via Bluetooth socket, one tablet android and a bluetooth device like reader barcode, up to now it's ok, the problem is, when a read the barcode by the bluetooth device and I send it to tablet, the bar code sometimes it's sent in two parts, for example, if I read a barcode with content "212154521212", the tablet receive "2121" and after "54521212", Anyone know tell me what should I do to avoid this?
Thanks in advanced.
My code that read the data from bluetooth device:
[code]
private class ConnectedThread extends Thread {
private final InputStream mmInStream;
private BluetoothSocket socket;
public ConnectedThread(BluetoothSocket socket) {
this.socket = socket;
InputStream tmpIn = null;
try {
tmpIn = socket.getInputStream();
} catch (IOException e) {
new LogDeErrosRodesTablet(e);
Log.e(TAG, e.getMessage());
Log.e(TAG, "Erro no construtor da classe ConnectedThread.");
}
mmInStream = tmpIn;
}
public void run() {
// continua lendo o inputstream até ocorrer um erro
while (true) {
int read = 0;
byte[] buffer = new byte[128];
do {
try {
read = mmInStream.read(buffer);
Log.e(TAG, "read: " + read);
final String data = new String(buffer, 0, read);
Log.e(TAG, "data: " + data);
//TODO
//send data only (bar code) only after read all
Bundle bundle = new Bundle();
bundle.putString(TelaInserirPedido.CODIGO_BARRAS, data);
Message message = new Message();
message.what = TelaInserirPedido.MSG_COD_BARRAS;
message.setData(bundle);
//Send a message with data
handler.sendMessage(message);
} catch(Exception ex) {
read = -1;
return;
}
Log.e(TAG, "inside while.");
} while (read > 0);
Log.e(TAG, "outside of while.");
}
}
public void cancel () {
try {
socket.close ();
} catch ( IOException e) { }
}
}
[/code]

This isn't a Bluetooth error. The Bluetooth device is sending all of the data to your application, but you are reading the stream before all of the data have been received. You could check for the amount of bytes available() on the stream before reading, if you know the exact length of the data; you could concatenate the results of all of the reads until you reach a known end point. Or you could put in an arbitrary time delay and hope the transmission completed in that time.
You would create the Bundle and Message after the while loop that collects the input string, because you don't know the entire string until that loop finishes. (Unless you are expecting multiple strings in one connection, in which case you need more complex code to handle partial numbers).

Use OutputStream.flush() to force send the all data.

SSLProtocolException when reading https responses on Android 2.3.3 devices

I'm facing a problem with a bug (Issue 16121) that was introduced in Gingerbread 2.3.3 and fixed with 2.3.4.
Reading the response of a https request throws an SSLProtocolException after reading ~40kB from the inputstream. The problem is described at Issue 16121. At the bottom of the page is a android project that reveals the bug. The bug report originates from user 'Alex' on stackoverflow (question).
I have an app in the market that sends many different https requests. Most of them need to receive up to 200kB. I cannot change anything on the server side. I use the DefaultHttpClient to send https requests.
How can I efficiently solve that problem?
Using a different https api? Which https api?

Here are some sample methods, as noted in the comment, I am using CharTerminatedInputStream, under the Apache license. The URL to see it is in the comment as well.
private static final int BUFFER_SIZE = 4096;
private static final char[] TERMINATOR = new char[]{'\r', '\n', '\r', '\n'};
/**
* Simple SSL connect example to avoid Issue 15356 on Android 2.3.3
*
* #param host The host/server name
* #param port The TCP port to use (443 is default for HTTP over SSL)
* #param file The file you are requesting (/path/to/file/on/server.doc)
* #param fileOut Your <code>OutputStream</code> for the file you are writing to
* #throws Exception If any error occurs - obviously should be improved for your implementation
*/
private static void downloadFileOverSSL(String host, int port, String file, OutputStream fileOut) throws Exception {
PrintWriter socketOut = null;
InputStream socketIn = null;
try {
// create a socket to talk to the server on
SocketFactory factory = SSLSocketFactory.getDefault();
Socket socket = factory.createSocket(host, port);
// we'll use this to send our request to the server
socketOut = new PrintWriter(new OutputStreamWriter(socket.getOutputStream()));
//This is what Java was sending using URLConnection, and it works here too...
// You can always change this to something both your app and server will understand depending how it is setup
// This is the least you need in the request:
/*String requestStr = "GET " + file + " HTTP/1.1\r\n" +
"Host: " + host + "\r\n" +
"\r\n";*/
String requestStr = "GET " + file + " HTTP/1.1\r\n" +
"Host: " + host + "\r\n" +
"User-Agent: Java/1.6.0_25\r\n" +
"Accept: text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2" +
"Connection: keep-alive\r\n" +
"\r\n";
//Log.i(getLogTag(), "Request being sent: `" + requestStr + "\"");
// send the request to the server
socketOut.print(requestStr);
socketOut.flush();
// this reads the server's response
socketIn = socket.getInputStream();
/*
Write the results into our local file's output stream
*/
// This is the tricky part, the raw socket returns the HTTP 200 response and headers.
// This can probably be optimized, but it's just reading through until it finds \r\n\r\n
// You can use something like CharTerminatedInputStream
// (ref: http://www.java2s.com/Tutorial/Java/0180__File/AnInputStreamclassthatterminatesthestreamwhenitencountersaparticularbytesequence.htm)
CharTerminatedInputStream charTermInput = new CharTerminatedInputStream(socketIn, TERMINATOR);
while (charTermInput.read() != -1) {
// -1 indicates a match was made, IOException or ProtocolException thrown if match not made by end of stream
}
int numBytesRead;
byte[] buffer = new byte[BUFFER_SIZE];
while ((numBytesRead = socketIn.read(buffer, 0, BUFFER_SIZE)) != -1) {
fileOut.write(buffer, 0, numBytesRead);
//Log.d(getLogTag(), "Reading data [" + numBytesRead + "]: " + new String(buffer, 0, numBytesRead));
}
fileOut.flush();
} finally {
safeClose(socketOut);
safeClose(socketIn);
safeClose(fileOut);
}
}
private static void safeClose(Closeable closeable) {
if (closeable != null) {
try {
closeable.close();
} catch (IOException ioe) {
//Log.w(getLogTag(), "Failed to close stream", ioe);
}
}
}