DCAT Toolkit

Python toolkit for working with DCAT (Data Catalog Vocabulary) metadata using Pydantic models with RDF serialization/deserialization.

Overview

This project provides a Python toolkit for working with DCAT (Data Catalog Vocabulary), an RDF vocabulary designed for interoperability between data catalogs published on the Web. The toolkit implements the W3C DCAT standard using Pydantic models and provides utilities for creating, manipulating, and serializing DCAT metadata.

Key Features:

• Pydantic-based models with full validation and type safety
• Python implementation of DCAT classes (Catalog, Dataset, Distribution, DataService, etc.)
• Support for DCAT 3.0 specification
• RDF serialization/deserialization support via rdflib (Turtle, RDF/XML, JSON-LD, N-Triples)
• Round-trip conversion between Python objects and RDF
• Type-safe API with comprehensive type hints
• Support for DCAT Application Profiles (DCAT-AP, DCAT-US, DCAT-AP-HVD)

Installation

Install from PyPI

pip install dartfx-dcat

Install from Source

git clone https://github.com/DataArtifex/dcat-toolkit.git
cd dcat-toolkit
pip install -e .

Development Setup (uv)

uv sync --group dev
uv run --with pre-commit pre-commit install

You can run all local checks with:

uv run --with pre-commit pre-commit run --all-files

Usage

Here's a quick example of how to create a DCAT catalog with a dataset:

from dartfx.dcat import dcat

# Create a catalog
catalog = dcat.Catalog(id="my-catalog")
catalog.add_title("My Data Catalog", lang="en")
catalog.add_description("A catalog of open datasets", lang="en")

# Create a dataset
dataset = dcat.Dataset(id="dataset-1")
dataset.add_title("Population Statistics", lang="en")
dataset.add_description("Annual population statistics by region", lang="en")
dataset.add_keyword("population")
dataset.add_keyword("statistics")
dataset.add_theme("http://example.org/themes/demographics")

# Create a distribution
distribution = dcat.Distribution(id="dist-1")
distribution.title.append("CSV Distribution")
distribution.add_download_url("http://example.org/data/population.csv")
distribution.add_media_type("text/csv")

# Link them together
dataset.add_distribution(distribution)
catalog.add_dataset(dataset)

# Serialize to RDF Turtle format
turtle = catalog.to_rdf(format='turtle')
print(turtle)

# Serialize to RDF/XML
xml = catalog.to_rdf(format='xml')

# Get the RDF graph directly
graph = catalog.to_rdf_graph()

# Deserialize from RDF
from rdflib import URIRef
subject = URIRef("http://www.w3.org/ns/dcat#my-catalog")
restored_catalog = dcat.Catalog.from_rdf(turtle, format='turtle', subject=subject)

Key Features

• Pydantic-based Models: Full validation and type safety
• RDF Serialization: Convert to Turtle, RDF/XML, JSON-LD, N-Triples
• RDF Deserialization: Load DCAT metadata from RDF formats
• Round-trip Support: Lossless conversion between Python objects and RDF
• Type Hints: Complete type annotations for better IDE support

For additional examples and profile-specific guides, see docs/source.

Contributing

1. Fork it!
2. Create your feature branch: git checkout -b my-new-feature
3. Commit your changes: git commit -am 'Add some feature'
4. Push to the branch: git push origin my-new-feature
5. Submit a pull request :D

License

The MIT License (MIT)

Copyright (c) 2024 Pascal L.G.A. Heus

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.