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core

Overview

This package provides a set of APIs to define many aspects of a project in a way that conforms to the MIAPPE standard. MIAPPE conformant metadata is stored as an RDF graph and can be serialised to a json-ld file that conforms to the RO-Crate standard.

Quick-start

Install either pdm or poetry. Note: install poetry or pdm globally with pipx so you can reuse the package manager for other repos. In this document, we will use pdm since it is the command used in the make file.

pipx install pdm

Install dependencies:

pdm install

Example

import datetime
from dataclasses import dataclass
from dataclasses import field as dc_field
from typing import Annotated, NamedTuple, TypedDict

from msgspec import field
from rdflib.namespace import FOAF

from appnlib.core.schema import FieldInfo, IDRef, Schema
from appnlib.core.struct import LinkedDataClass, Registry


class Person(LinkedDataClass):
    __rdf_resource__ = FOAF.Person
    __rdf_context__ = FOAF._NS
    firstName: str
    lastName: str
    birthdate: datetime.date
    mbox: str | None = None
    knows: Annotated[
        list[str],
        FieldInfo(ref=FOAF.knows, range=IDRef(ref=FOAF.Person), repeat=True),
    ] = field(default_factory=list)


class Group(LinkedDataClass):
    __schema__ = Schema(
        __rdf_resource__=FOAF.Group,
        attrs={
            "member": FieldInfo(FOAF.member, range=IDRef(ref=FOAF.Person), repeat=True)
        },
    )
    member: list[str]


ID_POOL = {
    "BarrackObama": "http://example.org/BarrackObama",
    "JoeBiden": "http://example.org/JoeBiden",
    "BillClinton": "http://example.org/BillClinton",
    "AlGore": "http://example.org/AlGore",
}

Obama = Person(
    id=ID_POOL["BarrackObama"],
    firstName="Barrack",
    lastName="Obama",
    birthdate=datetime.datetime(1961, 8, 4),
    knows=[ID_POOL["JoeBiden"], ID_POOL["BillClinton"]],
)

Biden = Person(
    id=ID_POOL["JoeBiden"],
    firstName="Joe",
    lastName="Biden",
    birthdate=datetime.date(1942, 11, 20),
    knows=[ID_POOL["BarrackObama"]],
)

Clinton = Person(
    id=ID_POOL["BillClinton"],
    firstName="Bill",
    lastName="Clinton",
    birthdate=datetime.datetime(1946, 8, 19),
    knows=[ID_POOL["AlGore"], ID_POOL["BarrackObama"]],
)

AlGore = Person(
    id=ID_POOL["AlGore"],
    firstName="Al",
    lastName="Gore",
    birthdate=datetime.datetime(1948, 3, 31),
    knows=[ID_POOL["BillClinton"]],
)

Presidents = Group(
    id="http://example.org/USPresidents",
    member=[ID_POOL["BarrackObama"], ID_POOL["BillClinton"], ID_POOL["JoeBiden"]],
)
VicePresidents = Group(
    id="http://example.org/USVicePresidents",
    member=[ID_POOL["AlGore"], ID_POOL["JoeBiden"]],
)

registry = Registry()

registry.serialize(destination="WhiteHouse.json", context={"foaf": FOAF._NS})

Design

Each Python LinkedDataClass defines a schema for a particular resource (rdfs:Resource). The resource type information is stored using the special attribute __rdf_resource__. Each instance of a LinkedDataClass has an id that uniquely identify any instance of a resource within the graph.

The attributes of a semantic class define a property (rdf:Property) and will by default have __rdf_resource__ as its domain.

Appendix

Special attributes

id

Represents the identifier for a resource instance. id values can be supplied by the user, in which case, it must be a globally unique URI, or minted automatically as a blank node.

__rdf_resource__

__rdf_resource__ is a read-only class attribute that describes the type of a resource instance. For any instance of a LinkedDataClass, this information will be serialised as (id, rdf.type, __rdf_resource).

MIAPPE Schema Language

RDF Terms

  • IRI (URIRef in rdflib): a unicode string conforming to IRI syntax
  • Literal (Literal in rdflib): literal values such as string, numbers and dates.
  • Blank (BNode in rdflib): local identifiers used in some concrete RDF store/syntaxes. Locally scoped to the file or RDF store and are not persistent or portal identifiers for blank nodes.

Serialisation Note:

The official document (See section 3.5) specifies that IRIs may be minted to replace Blank Nodes in an RDF graph. This IRIs should be globally unique. The official document recommends using /<well-known>/genid/<BNode value> to replace a BNode with an IRI, where well-known is a well-known IRI.

RDF Grammar in rdflib syntax

subject := URIRef | BNode
predicate := URIRef
object := URIRef | Literal | BNode
term := URIRef | Literal | BNode
statement := (subject, predicate, object)
graph := {statement+}
graphName := URIRef | BNode
namedGraph := (graphName, graph)
defaultGraph := graph?
dataset := (defaultGraph, {namedGraph+})