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oxigraph/python/src/sparql.rs

220 lines
7.5 KiB

use crate::model::*;
use crate::store_utils::*;
use oxigraph::sparql::*;
use pyo3::exceptions::{RuntimeError, SyntaxError, TypeError, ValueError};
use pyo3::prelude::*;
use pyo3::{PyIterProtocol, PyMappingProtocol, PyNativeType, PyObjectProtocol};
pub fn build_query_options(
use_default_graph_as_union: bool,
default_graph_uris: Option<&PyAny>,
named_graph_uris: Option<&PyAny>,
default_graph: Option<&PyAny>,
named_graphs: Option<&PyAny>,
) -> PyResult<QueryOptions> {
if default_graph_uris.is_some() && default_graph.is_some() {
return Err(ValueError::py_err(
"The query() method default_graph and default_graph_uris parameters cannot be set at the same time",
));
}
if named_graph_uris.is_some() && named_graphs.is_some() {
return Err(ValueError::py_err(
"The query() method named_graphs and named_graph_uris parameters cannot be set at the same time",
));
}
let mut options = QueryOptions::default();
if use_default_graph_as_union {
options = options.with_default_graph_as_union();
}
if let Some(default_graph) = default_graph.or(default_graph_uris) {
if let Ok(default_graphs) = default_graph.iter() {
if default_graph.is_empty()? {
return Err(ValueError::py_err(
"The query() method default_graph argument cannot be empty list",
));
}
for default_graph in default_graphs {
options = options.with_default_graph(extract_graph_name(default_graph?)?);
}
} else if let Ok(default_graph) = extract_graph_name(default_graph) {
options = options.with_default_graph(default_graph);
} else {
return Err(ValueError::py_err(
format!("The query() method default_graph argument should be a NamedNode, a BlankNode, the DefaultGraph or a not empty list of them. {} found", default_graph.get_type()
)));
}
}
if let Some(named_graphs) = named_graphs.or(named_graph_uris) {
if named_graphs.is_empty()? {
return Err(ValueError::py_err(
"The query() method nammed_graphs argument cannot be empty",
));
}
for named_graph in named_graphs.iter()? {
options = options.with_named_graph(extract_named_or_blank_node(named_graph?)?);
}
}
Ok(options)
}
pub fn query_results_to_python(py: Python<'_>, results: QueryResults) -> PyResult<PyObject> {
Ok(match results {
QueryResults::Solutions(inner) => PyQuerySolutions { inner }.into_py(py),
QueryResults::Graph(inner) => PyQueryTriples { inner }.into_py(py),
QueryResults::Boolean(b) => b.into_py(py),
})
}
/// Tuple associating variables and terms that are the result of a SPARQL ``SELECT`` query.
///
/// It is the equivalent of a row in SQL.
///
/// It could be indexes by variable name (:py:class:`Variable` or :py:class:`str`) or position in the tuple (:py:class:`int`).
///
/// >>> store = SledStore()
/// >>> store.add(Quad(NamedNode('http://example.com'), NamedNode('http://example.com/p'), Literal('1')))
/// >>> solution = next(store.query('SELECT ?s ?p ?o WHERE { ?s ?p ?o }'))
/// >>> solution[Variable('s')]
/// <NamedNode value=http://example.com>
/// >>> solution['s']
/// <NamedNode value=http://example.com>
/// >>> solution[0]
/// <NamedNode value=http://example.com>
#[pyclass(unsendable, name = QuerySolution)]
pub struct PyQuerySolution {
inner: QuerySolution,
}
#[pyproto]
impl PyObjectProtocol for PyQuerySolution {
fn __repr__(&self) -> String {
let mut buffer = String::new();
buffer.push_str("<QuerySolution");
for (k, v) in self.inner.iter() {
buffer.push(' ');
buffer.push_str(k.as_str());
buffer.push('=');
term_repr(v.as_ref(), &mut buffer)
}
buffer.push('>');
buffer
}
}
#[pyproto]
impl PyMappingProtocol for PyQuerySolution {
fn __len__(&self) -> usize {
self.inner.len()
}
fn __getitem__(&self, input: &PyAny) -> PyResult<Option<PyObject>> {
if let Ok(key) = usize::extract(input) {
Ok(self
.inner
.get(key)
.map(|term| term_to_python(input.py(), term.clone())))
} else if let Ok(key) = <&str>::extract(input) {
Ok(self
.inner
.get(key)
.map(|term| term_to_python(input.py(), term.clone())))
} else if let Ok(key) = input.downcast::<PyCell<PyVariable>>() {
let key = &*key.borrow();
Ok(self
.inner
.get(<&Variable>::from(key))
.map(|term| term_to_python(input.py(), term.clone())))
} else {
Err(TypeError::py_err(format!(
"{} is not an integer of a string",
input.get_type().name(),
)))
}
}
}
/// An iterator of :py:class:`QuerySolution` returned by a SPARQL ``SELECT`` query
///
/// >>> store = SledStore()
/// >>> store.add(Quad(NamedNode('http://example.com'), NamedNode('http://example.com/p'), Literal('1')))
/// >>> list(store.query('SELECT ?s WHERE { ?s ?p ?o }'))
/// [<QuerySolution s=<NamedNode value=http://example.com>>]
#[pyclass(unsendable, name = QuerySolutions)]
pub struct PyQuerySolutions {
inner: QuerySolutionIter,
}
#[pymethods]
impl PyQuerySolutions {
/// :return: the ordered list of all variables that could appear in the query results
/// :rtype: list(Variable)
///
/// >>> store = SledStore()
/// >>> store.query('SELECT ?s WHERE { ?s ?p ?o }').variables
/// [<Variable value=s>]
#[getter]
fn variables(&self) -> Vec<PyVariable> {
self.inner
.variables()
.iter()
.map(|v| v.clone().into())
.collect()
}
}
#[pyproto]
impl PyIterProtocol for PyQuerySolutions {
fn __iter__(slf: PyRefMut<Self>) -> Py<Self> {
slf.into()
}
fn __next__(mut slf: PyRefMut<Self>) -> PyResult<Option<PyQuerySolution>> {
Ok(slf
.inner
.next()
.transpose()
.map_err(map_evaluation_error)?
.map(move |inner| PyQuerySolution { inner }))
}
}
/// An iterator of :py:class:`Triple` returned by a SPARQL ``CONSTRUCT`` or ``DESCRIBE`` query
///
/// >>> store = MemoryStore()
/// >>> store.add(Quad(NamedNode('http://example.com'), NamedNode('http://example.com/p'), Literal('1')))
/// >>> list(store.query('CONSTRUCT WHERE { ?s ?p ?o }'))
/// [<Triple subject=<NamedNode value=http://example.com> predicate=<NamedNode value=http://example.com/p> object=<Literal value=1 datatype=<NamedNode value=http://www.w3.org/2001/XMLSchema#string>>>]
#[pyclass(unsendable, name = QueryTriples)]
pub struct PyQueryTriples {
inner: QueryTripleIter,
}
#[pyproto]
impl PyIterProtocol for PyQueryTriples {
fn __iter__(slf: PyRefMut<Self>) -> Py<Self> {
slf.into()
}
fn __next__(mut slf: PyRefMut<Self>) -> PyResult<Option<PyTriple>> {
Ok(slf
.inner
.next()
.transpose()
.map_err(map_evaluation_error)?
.map(|t| t.into()))
}
}
pub fn map_evaluation_error(error: EvaluationError) -> PyErr {
match error {
EvaluationError::Parsing(error) => SyntaxError::py_err(error.to_string()),
EvaluationError::Io(error) => map_io_err(error),
EvaluationError::Query(error) => ValueError::py_err(error.to_string()),
_ => RuntimeError::py_err(error.to_string()),
}
}