packetizr

Intro

packetizr is a non production ready code generation tool for binary serialization based on contracts. Right now it's just being used on a hobby game server project. Any suggestions or advice would be greatly appreciated.

Installation

npm i -g packetizr

Usage

packetizr gen -l {language} -o {output directory} [contract file]

Examples

packetizr gen -l go contract.yml # generates go source files for "contract.yml"

packetizr gen --help # display help

Contract Structure

Packets

Should be an array of packet definitions and each definition should have:

• header (unsigned numeric value) packet identifier, must be unique
• name (string) packet name, must be unique
• fields (object) packet model

packets:
  - header: 1
    name: PositionMessage
    fields:
      x:
        type: float32
      y:
        type: float32
  - header: 2
    name: ChatMessage
    fields:
      userId:
        type: char
        length: 36
      message:
        type: varchar
...

Fields

• type (string) corresponding to any of the supported types required
• length (unsigned numeric value) used to specify the length of a char type field, required when type is char
• schema (string) name of a schema defined in components.schemas, required when type is object
• items (object) describe the type of each element, should be present when type is array.

...
    fields:
      age:
        type: uint8
      name:
        type: char
        length: 10
      address:
        type: object
        schema: Address
      phoneNumbers:
        type: array
        items:
          type: char
          length: 10
...

Supported Types

| name | size(bytes) | type | |---|---|---| | int32 | 4 | basic | | int16 | 2 | basic | | int8 | 1 | basic | | uint32 | 4 | basic | | uint16 | 2 | basic | | uint8 | 1 | basic | | float32 | 4 | basic | | char | {defined fixed length} | basic | | varchar | 1+n | basic | | object | sum({each attributes size}) | complex | | array | 1 + (n * {each item size}) | complex |

Complex Types - object

Objects should have an schema which describes its attribute types

packets:
  - header: 1
    name: LoginMessage
    fields:
      timestamp:
        type: uint32
      information:
        type: object
        schema: LoginInformation
components:
  schemas:
    LoginInformation
      username: 
        type: varchar
      password:
        type: varchar

Complex Types - array

Array items can be described using the following properties:

• type (string) any supported types, except for array required
• length (unsigned numeric value) used to specify the length of a char type field, required when type is char
• schema (string) name of a schema defined in components.schemas, required when type is object

    fields:
      arrayOfIntegers:
        type: array
        items:
          type: int32
      arrayOfObjects:
        type: array
        items: 
          type: object
          schema: LoginInformation

Schemas

Schemas describe specific object structure using the same properties that fields

...

components:
  schemas:
    LoginInformation
      username: 
        type: varchar
      password:
        type: varchar
    Position:
      x:
        type: float32
      y:
        type: float32

Example

packets:
  - header: 1
    name: NumbersMessage
    fields:
      int32Field:
        type: int32
      float32Field:
        type: float32
      int16Field:
        type: int16
      int8Field:
        type: int8
      uint32Field:
        type: uint32
      uint16Field:
        type: uint16
      uint8Field:
        type: uint8
  - header: 2
    name: StringsMessage
    fields:
      varcharField:
        type: varchar
      charField:
        type: char
        length: 4
  - header: 3
    name: CustomMessage
    fields:
      parentField:
        type: object
        schema: ParentObject
  - header: 4
    name: ArraysMessage
    fields:
      customArray:
        type: array
        items:
          type: object
          schema: ParentObject
      numericArray:
        type: array
        items:
          type: int32
      charArray:
        type: array
        items:
          type: char
          length: 6
      varcharArray:
        type: array
        items:
          type: varchar
      singleByteArray:
        type: array
        items:
          type: int8
components:
  schemas:
    ParentObject:
      childField:
        type: object
        schema: ChildObject
    ChildObject:
      varcharField:
        type: varchar
      charField:
        type: char
        length: 10