schema-markdown 0.9.11

Human-friendly schema definition language and schema validator

Schema Markdown is a human-friendly schema definition language and schema validator. Here are its features at a glance:

• Schema-validate JSON objects

• Human-friendly schema definition

• Validates member value and length contraints

• Validation type-massages string member values

• Pure Python

Links

• Documentation on GitHub Pages

• Package on pypi

• Source code on GitHub

Usage

To schema-validate an object, first parse its Schema Markdown using the SchemaMarkdownParser class:

>>> import schema_markdown
...
>>> parser = schema_markdown.SchemaMarkdownParser('''\
... # An aggregation function
... enum Aggregation
...     Average
...     Sum
...
... # An aggregate numerical operation
... struct Operation
...     # The aggregation function - default is "Sum"
...     optional Aggregation aggregation
...
...     # The numbers to operate on
...     int[len > 0] numbers
... ''')

Then, validate a dictionary object (or other object) using the validate_type function:

>>> schema_markdown.validate_type(parser.types, 'Operation', {
...     'numbers': [1, 2, '3', 4]
... })
{'numbers': [1, 2, 3, 4]}

Notice that the numerical input ‘3’ above is type-massaged to the integer 3 by validation. Validation fails if the object does not match the schema:

>>> try:
...     schema_markdown.validate_type(parser.types, 'Operation', {
...         'numbers': [1, 2, 'asdf', 4]
...     })
... except schema_markdown.ValidationError as exc:
...     str(exc)
"Invalid value 'asdf' (type 'str') for member 'numbers.2', expected type 'int'"

Validation also fails if a member contraint is violated:

>>> try:
...     schema_markdown.validate_type(parser.types, 'Operation', {
...         'numbers': []
...     })
... except schema_markdown.ValidationError as exc:
...     str(exc)
"Invalid value [] (type 'list') for member 'numbers', expected type 'array' [len > 0]"

Development

This project is developed using Python Build. Refer to the Python Build documentation for development instructions.