ili2c-python 0.1.19

Python utilities for ili2c (INTERLIS metamodel, parser, and repository helpers).

ili2c Python module

The Python edition of ili2c brings a focused subset of the INTERLIS toolchain into pure Python. It provides a light-weight metamodel that mirrors the Java API, a parser backed by ANTLR grammars, rendering helpers, and repository tools for discovering and caching INTERLIS models.

Installation

The package targets Python 3.9+. Install it from the repository root with pip:

pip install ./python

Use the editable mode during development:

pip install --editable ./python

Optional command line extras are not required—the package exposes everything through importable modules.

Package layout and features

The top-level package is ili2c with two subpackages:

ili2c.pyili2c

• parser contains parse() and ParserSettings, combining the ANTLR grammar with repository discovery. It loads .ili files and recursively resolves imports into a TransferDescription tree that mirrors the Java API.
• metamodel offers the Python data structures (e.g. TransferDescription, Model, Topic, Table, Attribute) with helper methods such as getModels(), find_model(), and elements_of_type() for navigating a parsed model graph.
• mermaid converts transfer descriptions into Mermaid class diagrams—ideal for quickly visualising the content of an INTERLIS model.

ili2c.ilirepository

• IliRepositoryManager walks configured repository URLs, follows links from ilisite.xml, picks the freshest version of each model, and can download the corresponding .ili file locally.
• RepositoryAccess reads ilimodels.xml metadata from HTTP(S) repositories or the file system and turns them into ModelMetadata records.
• RepositoryCache keeps HTTP downloads on disk, honours configurable TTLs, supports MD5 validation, and can sanitise paths so that repeated parses reuse cached models instead of hitting the network.

Parsing models

The parser resolves imports via ParserSettings. Configure model directories and repositories up front, then call parse():

import logging
from pathlib import Path

from ili2c.pyili2c import parser
from ili2c.pyili2c.metamodel import Table

logging.basicConfig(level=logging.INFO)

settings = parser.ParserSettings(
    ilidirs=["examples/models"],
    repositories=["http://models.interlis.ch/"],
)

transfer_description = parser.parse(
    Path("examples/models/DM01INTERLIS2_3.ili"),
    settings=settings,
)

for model in transfer_description.getModels():
    logging.info("Loaded model %%s (schema %%s)", model.getName(), model.getSchemaLanguage())

ParserSettings understands semicolon separated ILI_DIR strings, local folders, HTTP(S) repositories, and the %ILI_DIR placeholder. The parser stores already parsed files in a cache to avoid re-reading the same model twice.

Discovering model elements

The TransferDescription returned by the parser mirrors the Java API. Use find_model() to locate a model, then traverse its topics and tables or use the recursive elements_of_type() helper:

import logging

from ili2c.pyili2c import parser
from ili2c.pyili2c.metamodel import Table, TransferDescription

logging.basicConfig(level=logging.INFO)

transfer_description: TransferDescription = parser.parse("path/to/model.ili")
model = transfer_description.find_model("DM01INTERLIS2_3")
if model is None:
    raise RuntimeError("model not found")

logging.info("Model %s imports: %s", model.getName(), list(model.getImports()))

for topic in model.getTopics():
    logging.info("Topic %s contains %d classes", topic.getName(), len(topic.getClasses()))

for table in model.elements_of_type(Table):
    logging.info("Class %s has %d attributes", table.getScopedName(), len(table.getAttributes()))

Table instances expose methods such as getAttributes(), getConstraints(), isAbstract(), and getExtending() which mirror the Java original. Use them to inspect inheritance trees, mandatory attributes, or association ends.

Rendering Mermaid diagrams

Turn a parsed model into a diagram to share with collaborators:

import logging

from ili2c.pyili2c import parser
from ili2c.pyili2c.mermaid import render

logging.basicConfig(level=logging.INFO)

transfer_description = parser.parse("path/to/model.ili")
mermaid_source = render(transfer_description)
logging.info("Generated diagram:\n%s", mermaid_source)

The output can be pasted into any Mermaid-compatible viewer.

Working with repositories

The repository manager can discover models, fetch metadata, and download files:

import logging

from ili2c.ilirepository import IliRepositoryManager

logging.basicConfig(level=logging.INFO)

manager = IliRepositoryManager(["https://models.interlis.ch/"])
for metadata in manager.list_models():
    logging.info("%s %s -> %s", metadata.name, metadata.version, metadata.full_url)

metadata = manager.find_model("DM01INTERLIS2_3")
if metadata:
    local_path = manager.get_model_file(metadata.name)
    logging.info("Cached copy stored at %s", local_path)

IliRepositoryManager ranks multiple revisions by publishing date or version number and walks the repository network discovered via ilisite.xml so that linked repositories are searched automatically.

Repository cache behaviour

RepositoryCache stores downloads inside a configurable folder. Override it via ILI_CACHE or by passing base_dir. The cache key is derived from the URL and may use hashed filenames when ILI_CACHE_FILENAME=MD5 is set. Each request can specify a TTL—0 forces a re-download, None keeps the first copy indefinitely, and positive values trigger refreshes once the files grow stale. When MD5 hashes are provided the cache verifies them and re-fetches if they no longer match.

Sequence of resolving an import

sequenceDiagram
    participant User
    participant Parser
    participant Settings
    participant Manager
    participant Access
    participant Cache
    participant Repository

    User->>Parser: parse(path, settings)
    Parser->>Settings: resolve ilidirs & repositories
    Parser->>Manager: get_model_file(import_name)
    Manager->>Access: get_models(repository)
    Access->>Cache: fetch(ilimodels.xml)
    Cache->>Repository: HTTP GET /ilimodels.xml
    Repository-->>Cache: XML metadata
    Cache-->>Access: cached path
    Access-->>Manager: latest ModelMetadata
    Manager->>Cache: fetch(model.ili)
    Cache->>Repository: HTTP GET /model.ili
    Repository-->>Cache: ILI file
    Cache-->>Manager: local path
    Manager-->>Parser: filesystem path
    Parser-->>User: TransferDescription with imported model

Tips for exploring models

• Configure logging to INFO or DEBUG to observe cache hits, HTTP requests, and import resolution decisions.
• TransferDescription.getModels() returns immutable tuples—store mutable data on your own objects if needed.
• Use Model.elements_of_type(...) to search for specific element kinds anywhere inside a model without walking the nested structure manually.
• Combine the Mermaid renderer with elements_of_type() filters to render minimal diagrams that focus on selected topics or tables.

Troubleshooting

• If the parser cannot locate an import, ensure the model name (case-insensitive) matches the filename and that the directory is listed in ilidirs.
• For repository downloads behind a proxy, export the standard HTTP_PROXY environment variables—urllib honours them automatically.
• To inspect cached files, open the directory reported in log messages; removing files forces the cache to fetch them again on the next parse.