NextGraph
/
oxigraph
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Activity

Adds JSON deserializer

Browse Source 
Closes #47
pull/107/head
Tpt 3 years ago
parent 7b98d58b10
commit cde2672cdd
5 changed files with 377 additions and 88 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Show Stats Download Patch File Download Diff File
  1. 1
      lib/Cargo.toml
  2. 375
      lib/src/sparql/json_results.rs
  3. 78
      lib/src/sparql/model.rs
  4. 6
      lib/src/sparql/xml_results.rs
  5. 5
      testsuite/tests/sparql.rs

1
lib/Cargo.toml
Unescape View File

@ -45,6 +45,7 @@ sophia_api = { version = "0.6.2", optional = true }
http = "0.2"
httparse = { version = "1", optional = true }
native-tls = { version = "0.2", optional = true }
json-event-parser = "0.1"
[target.'cfg(target_arch = "wasm32")'.dependencies]
js-sys = "0.3"

375
lib/src/sparql/json_results.rs
Unescape View File

@ -1,80 +1,89 @@
//! Implementation of [SPARQL Query Results JSON Format](https://www.w3.org/TR/sparql11-results-json/)
use crate::error::invalid_input_error;
use crate::error::{invalid_data_error, invalid_input_error};
use crate::model::*;
use crate::sparql::error::EvaluationError;
use crate::sparql::model::*;
use std::io::Write;
use json_event_parser::{JsonEvent, JsonReader, JsonWriter};
use std::collections::BTreeMap;
use std::io;
use std::io::{BufRead, Write};
use std::rc::Rc;
pub fn write_json_results(
results: QueryResults,
mut sink: impl Write,
) -> Result<(), EvaluationError> {
pub fn write_json_results(results: QueryResults, sink: impl Write) -> Result<(), EvaluationError> {
let mut writer = JsonWriter::from_writer(sink);
match results {
QueryResults::Boolean(value) => {
sink.write_all(b"{\"head\":{},\"boolean\":")?;
sink.write_all(if value { b"true" } else { b"false" })?;
sink.write_all(b"}")?;
writer.write_event(JsonEvent::StartObject)?;
writer.write_event(JsonEvent::ObjectKey("head"))?;
writer.write_event(JsonEvent::StartObject)?;
writer.write_event(JsonEvent::EndObject)?;
writer.write_event(JsonEvent::ObjectKey("boolean"))?;
writer.write_event(JsonEvent::Boolean(value))?;
writer.write_event(JsonEvent::EndObject)?;
Ok(())
}
QueryResults::Solutions(solutions) => {
sink.write_all(b"{\"head\":{\"vars\":[")?;
let mut start_vars = true;
writer.write_event(JsonEvent::StartObject)?;
writer.write_event(JsonEvent::ObjectKey("head"))?;
writer.write_event(JsonEvent::StartObject)?;
writer.write_event(JsonEvent::ObjectKey("vars"))?;
writer.write_event(JsonEvent::StartArray)?;
for variable in solutions.variables() {
if start_vars {
start_vars = false;
} else {
sink.write_all(b",")?;
}
write_escaped_json_string(variable.as_str(), &mut sink)?;
writer.write_event(JsonEvent::String(variable.as_str()))?;
}
sink.write_all(b"]},\"results\":{\"bindings\":[")?;
let mut start_bindings = true;
writer.write_event(JsonEvent::EndArray)?;
writer.write_event(JsonEvent::EndObject)?;
writer.write_event(JsonEvent::ObjectKey("results"))?;
writer.write_event(JsonEvent::StartObject)?;
writer.write_event(JsonEvent::ObjectKey("bindings"))?;
writer.write_event(JsonEvent::StartArray)?;
for solution in solutions {
if start_bindings {
start_bindings = false;
} else {
sink.write_all(b",")?;
}
sink.write_all(b"{")?;
writer.write_event(JsonEvent::StartObject)?;
let solution = solution?;
let mut start_binding = true;
for (variable, value) in solution.iter() {
if start_binding {
start_binding = false;
} else {
sink.write_all(b",")?;
}
write_escaped_json_string(variable.as_str(), &mut sink)?;
writer.write_event(JsonEvent::ObjectKey(variable.as_str()))?;
match value {
Term::NamedNode(uri) => {
sink.write_all(b":{\"type\":\"uri\",\"value\":")?;
write_escaped_json_string(uri.as_str(), &mut sink)?;
sink.write_all(b"}")?;
writer.write_event(JsonEvent::StartObject)?;
writer.write_event(JsonEvent::ObjectKey("type"))?;
writer.write_event(JsonEvent::String("uri"))?;
writer.write_event(JsonEvent::ObjectKey("value"))?;
writer.write_event(JsonEvent::String(uri.as_str()))?;
writer.write_event(JsonEvent::EndObject)?;
}
Term::BlankNode(bnode) => {
sink.write_all(b":{\"type\":\"bnode\",\"value\":")?;
write_escaped_json_string(bnode.as_str(), &mut sink)?;
sink.write_all(b"}")?;
writer.write_event(JsonEvent::StartObject)?;
writer.write_event(JsonEvent::ObjectKey("type"))?;
writer.write_event(JsonEvent::String("bnode"))?;
writer.write_event(JsonEvent::ObjectKey("value"))?;
writer.write_event(JsonEvent::String(bnode.as_str()))?;
writer.write_event(JsonEvent::EndObject)?;
}
Term::Literal(literal) => {
sink.write_all(b":{\"type\":\"literal\",\"value\":")?;
write_escaped_json_string(literal.value(), &mut sink)?;
writer.write_event(JsonEvent::StartObject)?;
writer.write_event(JsonEvent::ObjectKey("type"))?;
writer.write_event(JsonEvent::String("literal"))?;
writer.write_event(JsonEvent::ObjectKey("value"))?;
writer.write_event(JsonEvent::String(literal.value()))?;
if let Some(language) = literal.language() {
sink.write_all(b",\"xml:lang\":")?;
write_escaped_json_string(language, &mut sink)?;
writer.write_event(JsonEvent::ObjectKey("xml:lang"))?;
writer.write_event(JsonEvent::String(language))?;
} else if !literal.is_plain() {
sink.write_all(b",\"datatype\":")?;
write_escaped_json_string(literal.datatype().as_str(), &mut sink)?;
writer.write_event(JsonEvent::ObjectKey("datatype"))?;
writer
.write_event(JsonEvent::String(literal.datatype().as_str()))?;
}
sink.write_all(b"}")?;
writer.write_event(JsonEvent::EndObject)?;
}
}
}
sink.write_all(b"}")?;
writer.write_event(JsonEvent::EndObject)?;
}
sink.write_all(b"]}}")?;
writer.write_event(JsonEvent::EndArray)?;
writer.write_event(JsonEvent::EndObject)?;
writer.write_event(JsonEvent::EndObject)?;
Ok(())
}
QueryResults::Graph(_) => Err(invalid_input_error(
@ -84,37 +93,253 @@ pub fn write_json_results(
}
}
fn write_escaped_json_string(s: &str, mut sink: impl Write) -> Result<(), EvaluationError> {
sink.write_all(b"\"")?;
for c in s.chars() {
match c {
'\\' => sink.write_all(b"\\\\"),
'"' => sink.write_all(b"\\\""),
c => {
if c < char::from(32) {
match c {
'\u{08}' => sink.write_all(b"\\b"),
'\u{0C}' => sink.write_all(b"\\f"),
'\n' => sink.write_all(b"\\n"),
'\r' => sink.write_all(b"\\r"),
'\t' => sink.write_all(b"\\t"),
c => {
let mut c = c as u8;
let mut result = [b'\\', b'u', 0, 0, 0, 0];
for i in (2..6).rev() {
let ch = c % 16;
result[i] = ch + if ch < 10 { b'0' } else { b'A' };
c /= 16;
}
sink.write_all(&result)
pub fn read_json_results(source: impl BufRead + 'static) -> Result<QueryResults, io::Error> {
let mut reader = JsonReader::from_reader(source);
let mut buffer = Vec::default();
let mut variables = None;
if reader.read_event(&mut buffer)? != JsonEvent::StartObject {
return Err(invalid_data_error(
"SPARQL JSON results should be an object",
));
}
loop {
let event = reader.read_event(&mut buffer)?;
match event {
JsonEvent::ObjectKey(key) => match key {
"head" => variables = Some(read_head(&mut reader, &mut buffer)?),
"results" => {
if reader.read_event(&mut buffer)? != JsonEvent::StartObject {
return Err(invalid_data_error("'results' should be an object"));
}
if reader.read_event(&mut buffer)? != JsonEvent::ObjectKey("bindings") {
return Err(invalid_data_error(
"'results' should contain a 'bindings' key",
));
}
if reader.read_event(&mut buffer)? != JsonEvent::StartArray {
return Err(invalid_data_error("'bindings' should be an object"));
}
return if let Some(variables) = variables {
let mut mapping = BTreeMap::default();
for (i, var) in variables.iter().enumerate() {
mapping.insert(var.clone(), i);
}
Ok(QueryResults::Solutions(QuerySolutionIter::new(
Rc::new(
variables
.into_iter()
.map(Variable::new)
.collect::<Result<Vec<_>, _>>()
.map_err(invalid_data_error)?,
),
Box::new(ResultsIterator {
reader,
buffer,
mapping,
}),
)))
} else {
Err(invalid_data_error(
"SPARQL tuple query results should contain a head key",
))
};
}
"boolean" => {
return if let JsonEvent::Boolean(v) = reader.read_event(&mut buffer)? {
Ok(QueryResults::Boolean(v))
} else {
Err(invalid_data_error("Unexpected boolean value"))
}
} else {
write!(sink, "{}", c)
}
_ => {
return Err(invalid_data_error(format!(
"Expecting head or result key, found {}",
key
)));
}
},
JsonEvent::EndObject => {
return Err(invalid_data_error(
"SPARQL results should contain a bindings key or a boolean key",
))
}
}?;
JsonEvent::Eof => return Err(io::Error::from(io::ErrorKind::UnexpectedEof)),
_ => return Err(invalid_data_error("Invalid SPARQL results serialization")),
}
}
}
fn read_head<R: BufRead>(
reader: &mut JsonReader<R>,
buffer: &mut Vec<u8>,
) -> io::Result<Vec<String>> {
if reader.read_event(buffer)? != JsonEvent::StartObject {
return Err(invalid_data_error("head should be an object"));
}
let mut variables = None;
loop {
match reader.read_event(buffer)? {
JsonEvent::ObjectKey(key) => match key {
"vars" => variables = Some(read_string_array(reader, buffer)?),
"link" => {
read_string_array(reader, buffer)?;
}
_ => {
return Err(invalid_data_error(format!(
"Unexpected key in head: '{}'",
key
)))
}
},
JsonEvent::EndObject => return Ok(variables.unwrap_or_else(Vec::new)),
_ => return Err(invalid_data_error("Invalid head serialization")),
}
}
}
fn read_string_array<R: BufRead>(
reader: &mut JsonReader<R>,
buffer: &mut Vec<u8>,
) -> io::Result<Vec<String>> {
if reader.read_event(buffer)? != JsonEvent::StartArray {
return Err(invalid_data_error("Variable list should be an array"));
}
let mut elements = Vec::new();
loop {
match reader.read_event(buffer)? {
JsonEvent::String(s) => {
elements.push(s.into());
}
JsonEvent::EndArray => return Ok(elements),
_ => return Err(invalid_data_error("Variable names should be strings")),
}
}
}
struct ResultsIterator<R: BufRead> {
reader: JsonReader<R>,
buffer: Vec<u8>,
mapping: BTreeMap<String, usize>,
}
impl<R: BufRead> Iterator for ResultsIterator<R> {
type Item = Result<Vec<Option<Term>>, EvaluationError>;
fn next(&mut self) -> Option<Result<Vec<Option<Term>>, EvaluationError>> {
self.read_next().map_err(EvaluationError::from).transpose()
}
}
impl<R: BufRead> ResultsIterator<R> {
fn read_next(&mut self) -> io::Result<Option<Vec<Option<Term>>>> {
let mut new_bindings = vec![None; self.mapping.len()];
loop {
match self.reader.read_event(&mut self.buffer)? {
JsonEvent::StartObject => (),
JsonEvent::EndObject => return Ok(Some(new_bindings)),
JsonEvent::EndArray | JsonEvent::Eof => return Ok(None),
JsonEvent::ObjectKey(key) => {
let k = *self.mapping.get(key).ok_or_else(|| {
invalid_data_error(format!(
"The variable {} has not been defined in the header",
key
))
})?;
new_bindings[k] = Some(self.read_value()?)
}
_ => return Err(invalid_data_error("Invalid result serialization")),
}
}
}
fn read_value(&mut self) -> io::Result<Term> {
enum Type {
Uri,
BNode,
Literal,
}
enum State {
Type,
Value,
Lang,
Datatype,
}
let mut state = None;
let mut t = None;
let mut value = None;
let mut lang = None;
let mut datatype = None;
if self.reader.read_event(&mut self.buffer)? != JsonEvent::StartObject {
return Err(invalid_data_error(
"Term serializations should be an object",
));
}
loop {
match self.reader.read_event(&mut self.buffer)? {
JsonEvent::ObjectKey(key) => match key {
"type" => state = Some(State::Type),
"value" => state = Some(State::Value),
"xml:lang" => state = Some(State::Lang),
"datatype" => state = Some(State::Datatype),
_ => {
return Err(invalid_data_error(format!(
"Unexpected key in term serialization: '{}'",
key
)))
}
},
JsonEvent::String(s) => match state {
None => (), // impossible
Some(State::Type) => match s {
"uri" => t = Some(Type::Uri),
"bnode" => t = Some(Type::BNode),
"literal" => t = Some(Type::Literal),
_ => {
return Err(invalid_data_error(format!(
"Unexpected term type: '{}'",
s
)))
}
},
Some(State::Value) => value = Some(s.to_owned()),
Some(State::Lang) => lang = Some(s.to_owned()),
Some(State::Datatype) => datatype = Some(s.to_owned()),
},
JsonEvent::EndObject => {
let value = value.ok_or_else(|| {
invalid_data_error("Term serialization should have a value key")
})?;
return match t {
None => Err(invalid_data_error(
"Term serialization should have a type key",
)),
Some(Type::Uri) => Ok(NamedNode::new(value)
.map_err(|e| invalid_data_error(format!("Invalid uri value: {}", e)))?
.into()),
Some(Type::BNode) => Ok(BlankNode::new(value)
.map_err(|e| invalid_data_error(format!("Invalid bnode value: {}", e)))?
.into()),
Some(Type::Literal) => Ok(match datatype {
Some(datatype) => Literal::new_typed_literal(
value,
NamedNode::new(datatype).map_err(|e| {
invalid_data_error(format!("Invalid datatype value: {}", e))
})?,
),
None => match lang {
Some(lang) => Literal::new_language_tagged_literal(value, lang)
.map_err(|e| {
invalid_data_error(format!("Invalid xml:lang value: {}", e))
})?,
None => Literal::new_simple_literal(value),
},
}
.into()),
};
}
_ => return Err(invalid_data_error("Invalid term serialization")),
}
}
}
sink.write_all(b"\"")?;
Ok(())
}

78
lib/src/sparql/model.rs
Unescape View File

@ -4,7 +4,7 @@ use crate::io::GraphSerializer;
use crate::model::*;
use crate::sparql::csv_results::{read_tsv_results, write_csv_results, write_tsv_results};
use crate::sparql::error::EvaluationError;
use crate::sparql::json_results::write_json_results;
use crate::sparql::json_results::{read_json_results, write_json_results};
use crate::sparql::xml_results::{read_xml_results, write_xml_results};
use rand::random;
use std::error::Error;
@ -30,11 +30,9 @@ impl QueryResults {
) -> Result<Self, io::Error> {
match format {
QueryResultsFormat::Xml => read_xml_results(reader),
QueryResultsFormat::Json => Err(invalid_input_error(
"JSON SPARQL results format parsing has not been implemented yet",
)), //TODO: implement
QueryResultsFormat::Json => read_json_results(reader),
QueryResultsFormat::Csv => Err(invalid_input_error(
"CSV and TSV SPARQL results format parsing is not implemented",
"CSV SPARQL results format parsing is not implemented",
)),
QueryResultsFormat::Tsv => read_tsv_results(reader),
}
@ -520,3 +518,73 @@ impl fmt::Display for VariableNameParseError {
}
impl Error for VariableNameParseError {}
#[test]
fn test_serialization_rountrip() -> Result<(), EvaluationError> {
use std::io::Cursor;
use std::str;
for format in &[
QueryResultsFormat::Xml,
QueryResultsFormat::Json,
QueryResultsFormat::Tsv,
] {
let results = vec![
QueryResults::Boolean(true),
QueryResults::Boolean(false),
QueryResults::Solutions(QuerySolutionIter::new(
Rc::new(vec![
Variable::new_unchecked("foo"),
Variable::new_unchecked("bar"),
]),
Box::new(
vec![
Ok(vec![None, None]),
Ok(vec![
Some(NamedNode::new_unchecked("http://example.com").into()),
None,
]),
Ok(vec![
None,
Some(NamedNode::new_unchecked("http://example.com").into()),
]),
Ok(vec![
Some(BlankNode::new_unchecked("foo").into()),
Some(BlankNode::new_unchecked("bar").into()),
]),
Ok(vec![Some(Literal::new_simple_literal("foo").into()), None]),
Ok(vec![
Some(
Literal::new_language_tagged_literal_unchecked("foo", "fr").into(),
),
None,
]),
Ok(vec![
Some(Literal::from(1).into()),
Some(Literal::from(true).into()),
]),
Ok(vec![
Some(Literal::from(1.33).into()),
Some(Literal::from(false).into()),
]),
]
.into_iter(),
),
)),
];
for ex in results {
let mut buffer = Vec::new();
ex.write(&mut buffer, *format)?;
let ex2 = QueryResults::read(Cursor::new(buffer.clone()), *format)?;
let mut buffer2 = Vec::new();
ex2.write(&mut buffer2, *format)?;
assert_eq!(
str::from_utf8(&buffer).unwrap(),
str::from_utf8(&buffer2).unwrap()
);
}
}
Ok(())
}

6
lib/src/sparql/xml_results.rs
Unescape View File

@ -318,8 +318,7 @@ impl<R: BufRead> ResultsIterator<R> {
}
let mut state = State::Start;
let mut new_bindings = Vec::default();
new_bindings.resize(self.mapping.len(), None);
let mut new_bindings = vec![None; self.mapping.len()];
let mut current_var = None;
let mut term: Option<Term> = None;
@ -474,13 +473,12 @@ impl<R: BufRead> ResultsIterator<R> {
State::Result => return Ok(Some(new_bindings)),
State::Binding => {
if let Some(var) = &current_var {
new_bindings[self.mapping[var]] = term.clone()
new_bindings[self.mapping[var]] = term.take()
} else {
return Err(
invalid_data_error("No name found for <binding> tag").into()
);
}
term = None;
state = State::Result;
}
State::Uri | State::BNode => state = State::Binding,

5
testsuite/tests/sparql.rs
Unescape View File

@ -85,15 +85,12 @@ fn sparql11_query_w3c_evaluation_testsuite() -> Result<()> {
"http://www.w3.org/2009/sparql/docs/tests/data-sparql11/syntax-query/manifest#test_61a",
"http://www.w3.org/2009/sparql/docs/tests/data-sparql11/syntax-query/manifest#test_62a",
"http://www.w3.org/2009/sparql/docs/tests/data-sparql11/syntax-query/manifest#test_65",
// SPARQL 1.1 JSON query results deserialization is not implemented yet
"http://www.w3.org/2009/sparql/docs/tests/data-sparql11/aggregates/manifest#agg-empty-group-count-1",
"http://www.w3.org/2009/sparql/docs/tests/data-sparql11/aggregates/manifest#agg-empty-group-count-2",
//BNODE() scope is currently wrong
"http://www.w3.org/2009/sparql/docs/tests/data-sparql11/functions/manifest#bnode01",
//Property path with unbound graph name are not supported yet
"http://www.w3.org/2009/sparql/docs/tests/data-sparql11/property-path/manifest#pp35",
//SERVICE name from a BGP
"http://www.w3.org/2009/sparql/docs/tests/data-sparql11/service/manifest#service5"
"http://www.w3.org/2009/sparql/docs/tests/data-sparql11/service/manifest#service5",
],
)
}

Write Preview
Loading…
Cancel
Save