Important

tei-rdfa is currently in beta and welcomes feedback from early adopters.

tei-rdfa

A Python utility for extracting RDFa data from TEI-XML documents.

Overview

tei_rdfa() is a dedicated function that extracts RDFa (Resource Description Framework in Attributes) data embedded in TEI (Text Encoding Initiative) XML documents and converts it into a standard RDF graph. The function handles native TEI namespace formatting through <prefixDef> elements (//tei:encodingDesc/tei:listPrefixDef/tei:prefixDef).¹

The tei-rdfa utility is a streamlined extractor tool that prioritizes simplicity and TEI-specific functionality, being intended to enable TEI+RDFa parsing in the absence of namespace-prefix attribution through HTML5-style prefix or XHTML/XML-style xmlns: attributes. For other uses, the pyRdfa distiller/parser library, which comprehensively implements the full RDFa specification, will be preferable.

Features

• Loads TEI-XML files from local paths or URLs
• Processes RDFa attributes about, typeof, property, rel, rev, resource, content
• Extracts and resolves namespace prefixes from TEI-specific <prefixDef> elements
• Generates RDF triples from embedded RDFa information
• Provides targeted extraction via XPath expressions
• Returns an RDFlib Graph object for further processing or serialization
• Implements robust error handling and informative error messages
• Offers verbose mode with detailed logging

Parameters

• xmlfile (str): File path or URL to a TEI-XML file (must have .xml or .tei extension)
• xpath_expr (str, optional): XPath expression to target specific elements for RDFa extraction; will otherwise target the XML root element
• verbose (bool, default=True): Controls logging output

Dependencies

• RDFlib: Core RDF functionality
• lxml: XML processing and XPath support

Implementation Details

The package includes several helper functions that handle specific aspects of RDFa extraction. It implements defensive programming practices with input validation and comprehensive error handling for common issues:

• Invalid file extensions
• Invalid XML syntax
• Invalid URLs or file paths
• Invalid XPath syntax
• Erroneous XPath queries

Error messages provide contextual information to facilitate debugging and resolution.

Installation

pip install tei-rdfa

Example Usage

from tei_rdfa import tei_rdfa

# Basic usage
graph = tei_rdfa('path/to/document.xml')

# With XPath to target specific elements
graph = tei_rdfa(
    xmlfile='https://example.org/document.tei',
    xpath_expr='//tei:person[2]',
    verbose=True
)

# Process resulting graph
print(graph.serialize(format='turtle'))

Directory Structure

tei_rdfa/
├── LICENSE
├── README.md
├── pyproject.toml
└── tei_rdfa/
    ├── __init__.py
    ├── requirements.txt
    └── ipynb/
        └── tei_rdfa.ipynb

The repository is organized as follows:

• tei_rdfa/ contains project metadata and configuration
• tei_rdfa/tei_rdfa/ contains the package implementation
• tei_rdfa/tei_rdfa/ipynb/ contains a Jupyter notebook demonstrating usage examples and error scenarios

---

Footnotes

1. See https://github.com/TEIC/TEI/issues/1860. ↩