#daily-protocol

daily - The protocol encoder and decoder for network communcation

Installation

npm install daily-protocol

Documentation

Unless you want to write your own low-level daily interfaces you don't need this module.

General

daily-protocol has two constructors Client and Server, they both wrap a binary duplex stream and exposes a duplex object stream.

var dailyProtocol = require('daily-protocol');

Client

To construct a client duplex stream:

client = new dailyProtocol.Client(net.connect(port, address));

client.on('data', function (response) { });
client.write(request);

Server

To construct a client duplex stream:

net.createServer(function (socket) {
  server = new dailyProtocol.Setver(socket);

  server.on('data', function (request) { });
  server.write(response);
});

Messages

The names are defined from the client perspective:

• requests can be written from the client and read from the server.
• response can be written from the server and read from the client.

The objects below are what you pass to .write or get from .read.

write -- request

{
  'type': 'write',
  'id': Number(UInt16),
  'seconds': Number(UInt32)
  'milliseconds': Number(UInt16),
  'level': Number(UInt8),
  'message': new Buffer()
}

write -- response

{
  'type': 'write',
  'id': Number(UInt16),
  'error': new Error() || null
}

read-start -- request

{
  'type': 'read-start',
  'startSeconds': Number(UInt32) || null,
  'startMilliseconds': Number(UInt16) || null,
  'endSeconds': Number(UInt32) || null,
  'endMilliseconds': Number(UInt16) || null,
  'levels': [Number(UInt4), Number(UInt4)]
}

read-start -- response

{
  'type': 'read-start',
  'seconds': Number(UInt32),
  'milliseconds': Number(UInt16),
  'level': Number(UInt8),
  'message': new Buffer()
}

read-stop -- request

{
  'type': 'read-stop'
}

read-stop -- response

{
  'type': 'read-stop',
  'error': new Error() || null
}

Binary protocol

The reason behind using a binary protocol it to completly eliminate JSON.stringify and JSON.parse on the server side. They are expensive and error prone compared to just reading and writing integers from a buffer.

Below you see how the messages are encoded, for how to seperate each message see the binarypoint module. But basicly its a UInt16BE there says how long the next message is in bytes.

 The binary protocol description symbols used below means:
  + : indicates required
  - : indicates optional

 request:
  + 1 byte: (0x01, 0x02, 0x03) = (write, read-start, read-stop)
 case: write
  + 2 byte: 16 bit id, resets on next timestamp
  + 4 byte: 32 bit second timestamp
  + 2 byte: 16 bit ms remain timestamp
  + 1 byte: (0x01 ... 0x09) = (level 1 ... level 9)
  + x byte: JSON string
  + 1 byte: 0x00 terminat command
 case: read-start
  + 1 byte: (0x19 ... 0x99) = (1-1, 1-2, ..., 1-9, 2-2, 2-3, ... 2-9, ..., 9-9)
  + 1 byte: 0x1- -> start time exists, 0x-1 end time exists
  - 4 byte: 32 bit second start timestamp
  - 2 byte: 16 bit ms remain start timestamp
  - 4 byte: 32 bit second end timestamp
  - 2 byte: 16 bit ms remain end timestamp
  + 1 byte: 0x00 terminat command
 case: read-stop
  + 1 byte: 0x00 terminat command

 response:
  + byte: (0x01, 0x02, 0x03) = (write, read-start, read-stop)
 case: write
  + 2 byte: 16 bit id, resets on next timestamp
  + 1 byte: (0x01, 0x02) = (no error, error)
  - x byte: JSON string
  + 1 byte: 0x00 terminat command
 case: read-start
  + 4 byte: 32 bit second timestamp
  + 2 byte: 16 bit ms remain timestamp
  + 1 byte: (0x01 ... 0x09) = (level 1 ... level 9)
  + x byte: JSON string
  + 1 byte: 0x00 terminat command
 case: read-stop
  + 1 byte: (0x01, 0x02) = (no error, error)
  - x byte: JSON string
  + 1 byte: 0x00 terminat command

##License

The software is license under "MIT"

Copyright (c) 2013 Andreas Madsen

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.