Implement DetailView feature

[lu-pl]

SPARQLModelAdapter.query currently only returns an rdfproxy.Page instance, with models assigned to the items field.

This roughly corresponds to a ListView in e.g. Django's Generic Display Views, so a respective DetailView would be an interesting feature to have.

[kevinstadler]

Example of desired usage:

class MyDetails(BaseModel):
    unique_id_field: str
    other_field: str

@app.get("/details")
def details(unique_identifier: str) -> MyDetails:

    # for now, library users need to inject an appropriate FILTER clause themselves, or
    # just pass any query as long as it only returns one result when run through the mapper.
    # (this solution is still a bit ugly because the query needs to refer to the binding var,
    # not the model field)
    query = f"""SELECT ?unique_id_field ?other_field
        WHERE { ... FILTER (?unique_id_field="{unique_identifier}"^^xsd:string) \}"""

    adapter = SPARQLModelAdapter(
        target="https://graphdb.r11.eu/repositories/RELEVEN",
        query=query,
        model=Details,
    )

    return adapter.query_one()

[kevinstadler]

With the 0-argument approach to query_one(), it is necessary to dynamically create a query with an appropriate FILTER (which needs to refer to the binding variable) in the endpoint definition. Since rdfproxy will anyhow soon have the capability to inject FILTERs (for the new model_bool implementation), it would be nice if it was also possible to pass a minimal filter argument (which can refer to the model fields) to query_one(), with rdfproxy taking care of injecting the appropriate filter. Example usage:

class MyDetails(BaseModel):
    unique_id_field: str
    other_field: str

@app.get("/details")
def details(unique_identifier_arg: str) -> MyDetails:
    adapter = SPARQLModelAdapter(
        target="https://graphdb.r11.eu/repositories/RELEVEN",
        query="""SELECT ?unique_id_field ?other_field WHERE {
  VALUES (?unique_id_field ?other_field) {
        ('what' 'ever')
        ('other' 'ever')
}""",
        model=Details,
    )

    # single field filter
    return adapter.query_one(unique_id_field = unique_identifier_arg)
    # or as a dict?
    #return adapter.query_one({ "unique_id_field": unique_identifier_arg })