Reading bytes from stream, and convert to string - delphi

Question

Im having a problem while reading a stream from a Client. Im using Delphi XE3 with Indy 10.
This Client, send me a tagged text data stream, that is in XML format. My problem start when i read data with a TIdTCPServer. With this code:
if Acontext.Connection.IoHandler.InputbufferisEmpty then
begin
Acontext.Connection.IoHandler.CheckforDataonSource(1000);
Acontext.Connection.IoHandler.CheckForDisconnect;
if Acontext.Connection.IoHandler.InputbufferisEmpty then Exit;
end;
Acontext.Connection.Iohandler.ReadBytes(Abuffer,
Acontext.connection.ioHandler.Inputbuffer.size);
data := BytesToString(Abuffer, Tencoding.bigendianUnicode);
Data is encoded in BigEndianUnicode. I noticed that when im recieving data, the server read and show me the data in 2 'blocks' diferents. If the server recieve the same data all the time, when i parse with BytesToString the data get "cut" at same char everytime.
Here is a result of what im getting:
<rootNode>
<Node1></Node1>
<Node2></Node2>
<
Node3></Node3>
<Node4></Node4>
The problem get bigger, when i assign that WideString to an XMLDocument. I get an Invalid at the top level of the document error.
Sometimes, i run the server and get all the data correct, without this error, but when i close the aplication and run it again, the server recieve the data corrupted.
Sorry, for my english. I need some help with this.

Answer 1

You are only reading whatever raw bytes happen to be in the IOHandler.InputBuffer at the moment you access it, so you are likely not reading the entire XML, or worse you are reading more data that follows the XML. If the client is sensible, it should be sending either the XML length before the XML data, or a unique terminator after the XML data. Either of which would allow you to read the entire XML by itself in full without having to resort to calling CheckforDataOnSource() at all (which you should be avoiding in most situations), eg:
len := AContext.Connection.IOHandler.ReadLongWord; // or however the XML length is sent
data := AContext.Connection.IOHandler.ReadString(len, IndyUTF16BigEndianEncoding);
Or:
data := AContext.Connection.IOHandler.ReadLn('the terminator here', IndyUTF16BigEndianEncoding);