What's this?

This is a Python module which decodes FM-12 (SYNOP) messages into a Python dictionary.

Example usage

from synack.parser import SYNOPParser

parser = SYNOPParser()
print(parser.parse("AAXX 01004 88889 12782 61506 10094 20047 30111 40197 53007 60001 81541 333 81656 86070"))

Or from the command line:

./cli parse "AAXX 01004 88889 12782 61506 10094 20047 30111 40197 53007 60001 81541 333 81656 86070"

Testing

PYTHONPATH=$PWD pytest tests/

Or

PYTHONPATH=$PWD python tests/test_generator.py

The test generator looks for .synop-.json pairs and checks the expected output with the actual JSON that was generated. If the .json file doesn't exist, it's created and the test passes vacuously (unless the parser fails to parse the message).

Architecture

synack/
├── builder.py
├── __init__.py
├── manage.py
├── parser.py
├── tables.py
└── tree.py

parser.py

Contains the parser for the messages. Builds the AST and handler errors.

builder.py

An intermediate layer to handle context, business rules, and build each subset of AST nodes

tree.py

Contains the definition of each AST node. The base ASTNode class contains support for automatic type conversion (str -> Any) with the aid of Python annotations and user-defined f"convert_{name}" functions. The conversion functions are called after the first conversion is made so if the field type is an index of a table (integer) and the conversion function transforms it into a float, the types of the type annotation and the real value might differ. Empty ("") values are saved as None. When writing conversion functions, assume any value can be null.

tables.py

Contains dictionaries with code tables and other mappings.

manage.py

Contains logic for the CLI.