JSON Interpolator

Overview

The JSON Interpolator is a Python package for validating and rendering templates with placeholders in JSON-like strings. It ensures placeholders are correctly formatted and substitutes them with provided values.

Features

• Validation: Ensures placeholders meet naming conventions.
• Rendering: Dynamically replaces placeholders with values from a dictionary.
• Object-Oriented Design: Encapsulated within the JSONInterpolator class for easy reuse and extension.

Placeholder Format

Placeholders should follow the syntax:

<<placeholder_name>>

Where:

• placeholder_name cannot start with a digit.
• placeholder_name must include at least one word character (letters, digits, or underscores).

Installation

Install from PyPI:

pip install json-interpolator

Or clone the repository for local development:

git clone https://github.com/mgeborges/json-interpolator.git
cd json-interpolator
pip install -e .

Usage

Example

from json_interpolator import JSONInterpolator

template = """
    {
        "name": <<name>>,
        "age": <<age>>,
        "roles": <<roles>>,
        "contact_info": <<contact_info>>,
        "is_active": <<is_active>>
    }
"""
params = {
    "name": "Alice",
    "age": 30,
    "roles": ["admin", "support"],
    "contact_info": {"email": "alice@company.com", "phone": "(555) 555-5555"},
    "is_active": True
}

result = JSONInterpolator.render_template(params, template)
print(result)
# Outputs:
# {
#     "name": "Alice",
#     "age": 30,
#     "roles": ["admin", "support"],
#     "contact_info": {"email": "alice@company.com", "phone": "(555) 555-5555"},
#     "is_active": true
# }

Please note that there is no need to wrap string placeholders with quotes inside templates. Doing so will lead to an invalid JSON.

Error Handling

Raises:

• ValueError if
  • invalid placeholders are found. Placeholder names are expected to follow the Python variables naming standards.
  • an invalid JSON is generated because of bad template formatting.
• TypeError if the template is not a string or if the parameters are not provided in a dictionary.

Testing

The package includes a test suite in the tests/ directory. To run tests:

Using unittest

Run tests from the root directory:

python -m unittest discover -s tests

Using pytest

If you prefer pytest:

pip install pytest
pytest

Dependencies

This project does not require external dependencies beyond the standard library.

License

MIT License