Changes between Version 17 and Version 18 of PacketEncoding

Timestamp:

06/05/14 06:33:00 (7 years ago)

Author:

Antoine Martin

Comment:

add more chunk info

PacketEncoding

@@ -6 +6 @@
 * [/wiki/NetworkProtocol Network Protocol] for the actual contents of the packets
 
+{{{#!div class="box"
+== Wire Format ==
+Each message may be split into multiple packets: large binary chunks (ie: compressed pixel data, large clipboard data, etc) will be sent in their own packet, skipping the generic compression layer.
+
+[[BR]]
+Each chunk is preceded by an 8 byte header containing:
+* the magic value "P" (char value 80 in decimal, {{{0x50}}} in hexadecimal)
+* one byte for protocol flags
+* one byte for compression level hint
+* one byte for the chunk index
+* one long (4 bytes) for the data size that follows
+
+[[BR]]
+The main chunk containing the message uses index 0 and it is encoded (see bencode / rencode below).
+The main message consists of a list of values, the first item is the packet type (see [[/wiki/NetworkProtocol]).
+The other chunks replace the item found at the specified index in the main chunk. (which should be empty)
+[[BR]]
+
+}}}
 
 {{{#!div class="box"
 == Bencode vs Rencode ==
-Each packet exchanged between the client and server is encoded using one of those two stream encoders:
+The main chunk is encoded using one of those two stream encoders:
 * The old [http://xpra.org/trac/browser/xpra/trunk/src/xpra/net/bencode.py bencode] mode (see [http://en.wikipedia.org/wiki/Bencode Bencode on wikipedia]): a modified bencoder which supports non string keys in dictionaries, and support for unicode
 * The newer/faster [http://xpra.org/trac/browser/xpra/trunk/src/xpra/net/rencode rencode] mode, based on [https://code.google.com/p/rencode/ this version] with minor tweaks/fixes
@@ -21 +40 @@
 == Pixels and Icons ==
 
-'''Note''': all window pixels, icons and cursors are sent using dedicated [/wiki/Encodings picture encodings] and bypass the stream encoder completely (for efficiency). Pixel compression is done in its own thread, to improve responsiveness.
+'''Note''': all window pixels, icons and cursors are sent in their own chunk using dedicated [/wiki/Encodings picture encodings] and bypass the stream encoder completely (for efficiency). Pixel compression is done in its own thread, to improve responsiveness.
 
-The only exception to this rule is the `RGB` encoding, which will use the stream encoder on the raw pixels (but still called from the pixel compression thread).
+The only exception to this rule is the `RGB` encoding, which will use the stream compression on the raw pixels (it still called from the pixel compression thread).
 }}}