easyprotocol 0.0.3

A library for quick protocol prototyping and parsing.

EasyProtocol

Introduction

A library for quick prototyping protocol parsing in python. Not the fastest, not the most efficient, not the coolest, but hopefully the easiest to modify and prototype with.

Quick Start

Installing

For now you have to install from source, this will be on pypi soon.

• Current Method

git clone https://github.com/joeferg425/EasyProtocol.git .
cd EasyProtocol
python -m pip install .

• Future, better method

python -m pip install easyprotocol

Example 1 - Making a Parser From a List of Fields

• Demo Code

  Lets parse something like the following.

  Name	Bit Count	Data Type
  id	8	8-bit int
  data count	16	16-bit unsigned int
  data	8	8-bit unsigned int

  Fixed frame definition. Nothing fancy.

  """Define your parser using simple python classes and familiar types."""
  from easyprotocol.base import ParseFieldList, hex
  from easyprotocol.fields import Int8Field, UInt8Field, UInt16Field
  
  # Make an instance of the modified list type and add your fields as the list items.
  exampleParser = ParseFieldList(
      # give the parser a name
      name="ExampleParser1",
      # define your fields in order
      default=[
          # give each field a name, some standard field types are already defined.
          Int8Field(name="id"),
          UInt16Field(name="count"),
          UInt8Field(name="data"),
      ],
  )
  
  # Some example data bytes to parse
  data = b"\x01\x00\x01\x80"
  print(f"input bytes:\t{data!r}")
  print(f"input hex:\t{hex(data)}\n")
  
  # Parse the bytes
  exampleParser.parse(data=data)
  
  # Print the parsed data to see what we got
  print(f"parsed:\t{exampleParser}")
  print(f"bytes:\t{bytes(exampleParser)!r}")
  print(f"hex:\t{exampleParser.hex_value}\n")
  
  # Make a new frame from known data to send somewhere (like a socket)
  exampleParser[0].value = 3
  exampleParser.value = [3, 257, 127]
  exampleParser.value = [3, 257, 127]
  print(f"parsed:\t{exampleParser}")
  print(f"bytes:\t{bytes(exampleParser)!r}")
  print(f"hex:\t{exampleParser.hex_value}\n")
  
  # You can access parsed elements of a ParseList by numeric index.
  for child in exampleParser.children.values():
      print(f'{child.name}:\t{child.value}\t"{child.string_value}"')
  print()
  
  # Wait, I don't really like hexadecimal
  exampleParser.string_format = "{}"
  for child in exampleParser.children.values():
      child.string_format = "{}"
  
  # Print the values again
  exampleParser[0].value = 3
  exampleParser.value = [3, 257, 127]
  exampleParser.value = [3, 257, 127]
  print(f"parsed:\t{exampleParser}")
  print(f"bytes:\t{bytes(exampleParser)!r}")
  print(f"hex:\t{exampleParser.hex_value}\n")
  for child in exampleParser.children.values():
      print(f'{child.name}:\t{child.value}\t"{child.string_value}"')
  

• Output

  input bytes:    b'\x01\x00\x01\x80'
  input hex:      01 00 01 80
  
  parsed: ExampleParser1: [id: 1, count: 0001(hex), data: 80(hex)]
  bytes:  b'\x01\x00\x01\x80'
  hex:    01 00 01 80
  
  parsed: ExampleParser1: [id: 3, count: 0101(hex), data: 7F(hex)]
  bytes:  b'\x03\x01\x01\x7f'
  hex:    03 01 01 7F
  
  id:     3       "3"
  count:  257     "0101(hex)"
  data:   127     "7F(hex)"
  
  parsed: ExampleParser1: [id: 3, count: 257, data: 127]
  bytes:  b'\x03\x01\x01\x7f'
  hex:    03 01 01 7F
  
  id:     3       "3"
  count:  257     "257"
  data:   127     "127"
      ```
  

Example 2 - Making a Parser from a Dictionary of Fields

• Demo Code

  Lets parse something like the following.

  Name	Bit Count	Data Type
  id	8	8-bit unsigned int
  count	16	16-bit unsigned int
  data array	8	8-bit unsigned int(s)

  Variable Frame size, handles a variable length array of uint8 chunks.

  """Define your parser using simple python classes and familiar types."""
  from typing import cast
  
  from easyprotocol.base import ParseFieldDict, ParseFieldList, hex
  from easyprotocol.fields import Int8Field, ParseArrayField, UInt8Field, UInt16Field
  
  # you can define your field classes before using them in a parser.
  ident = Int8Field(name="id")
  count = UInt16Field(
      name="count",
      # Let's modify the display of the field value
      string_format="{} data items",
  )
  data_array = ParseArrayField(
      name="data",
      count=count,
      array_item_class=UInt8Field,
      array_item_default=0,
  )
  
  # Make an instance of the modified list type and add your fields as the list items.
  exampleParser = ParseFieldDict(
      # give the parser a name
      name="ExampleParser",
      # define your fields in order
      default=[
          # give each field a name, some standard types are defined for you.
          ident,
          count,
          data_array,
      ],
  )
  
  # Some example data bytes to parse
  data = b"\x01\x00\x01\x80"
  print(f"input bytes:\t{data!r}\n")
  print(f"input hex:\t{hex(data)}\n")
  
  # Parse the bytes
  exampleParser.parse(data=data)
  # Print the parsed data to see what we got
  print(f"parsed:\t{exampleParser}")
  print(f"hex:\t{hex(exampleParser)}\n")
  
  # Make a new frame from known data to send somewhere (like a socket)
  exampleParser["id"].value = 3
  exampleParser["count"].value = 2
  exampleParser["data"].value = [
      127,
      UInt8Field(name="new data", default=15),
  ]
  
  print(f"parsed:\t{exampleParser}")
  print(f"hex:\t{hex(exampleParser)}\n")
  
  # You can access parsed elements of a ParseDict by name.
  idField = exampleParser[ident.name]
  dataCountField = exampleParser[count.name]
  dataField = cast(ParseFieldList, exampleParser[data_array.name])
  
  # The ArrayField is a list type, so children are accessed by numeric index.
  for child in exampleParser.values():
      print(f"{child.name}:\t{child.value}\t\t{child.bits_str}")
  

• Output

  input bytes:    b'\x01\x00\x01\x80'
  
  input hex:      01 00 01 80
  
  parsed: ExampleParser: {id: 1, count: 1 data items, data: [#0: 80(hex)]}
  hex:    01 00 01 80
  
  parsed: ExampleParser: {id: 3, count: 2 data items, data: [#0: 7F(hex), #1: 0F(hex)]}
  hex:    03 00 02 7F 0F
  
  id:     3               00000011:<b
  count:  2               0000000000000010:<b
  data:   [<UInt8Field> #0: 7F(hex), <UInt8Field> #1: 0F(hex)]            0111111100001111:<b
      ```