Questions about TCP sending and packet size

[roland]

@teletubo

I wrapped a class to read and write primitives over network, if you’re intersted, it works like this:

//Client sending message
PomPackage p = new PomPackage();
p.insert(35);
p.insert('c');
p.insert(new byte[30]);
sendPackage(p);

//Server reading the message:
int x = (Integer)p.pollQueue();
char c = (Character)p.pollQueue();
byte data[] = (byte[])p.pollQueue();

I might have reinvented the wheel but it works pretty nice, tell me if you’re intersted.

I actually made something very like this for my UDP library
Thanks for the offer though!

[princec]

@Riven

The problem of using an int for packet size (as opposed to a short) is that 1 client can hijack all available RAM of your process.

Always always always check every single byte of data that comes over a network for validity. ints fine but enforce maximum size, etc.

Cas

[delt0r]

private byte[] receiveData(int length) throws IOException //reading 22kb in one go, gets corrupted.
{
      byte[] data = new byte[length];
      is.read(data);
      return data;
}

Well there is your problem. is.read(byte[] data) is not is.readFully(). read(byte[] data) will block and read at least one byte or more, but does not block to fill the array, so you would often get partial fills, the rest would be old data in the array.

TCP really does take care of everything. Its just streams. But you still must use the streams correctly.

[sproingie]

And don’t cross the streams. Because that would be bad. ;D

[ra4king]

@sproingie

And don’t cross the streams. Because that would be bad. ;D

WIN!!! ;D ;D ;D

… sorry for hijacking the thread … going back to hiding now :persecutioncomplex: