nethserver-lib

This package contains common libraries for all system modules.

Task progress tracking

The system implements an utility called ptrack which is invoked from the web interface for handling long running processes like events.

Message format

Messages between the client and the server have three parts, following a "TLV" structure (http://en.wikipedia.org/wiki/Type-length-value):

[type] [length] [value]

• type is an unsigned char (1 byte)
• length is a short integer (2 bytes)
• value is a string (max length 65535 bytes)

Protocol

The client initiates the conversation by sending one message. Actually there are 4 types of message:

DECLARE  = 0x01
DONE     = 0x02
QUERY    = 0x03
PROGRESS = 0x04

The message payload is actually encoded in JSON syntax. It's an array structure, used as method arguments. For instance, a DECLARE message payload can be set to:

[0, 1.0, "First subtask"]

The server response type is a bitwise OR of the original request type, RESPONSE and possibly ERROR:

ERROR    = 0x40
RESPONSE = 0x80