Sparesults
==========
[](https://crates.io/crates/sparesults)
[](https://docs.rs/sparesults)
[](https://crates.io/crates/sparesults)
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Sparesults is a set of parsers and serializers for [SPARQL ](https://www.w3.org/TR/sparql11-overview/ ) query results formats.
It supports [SPARQL Query Results XML Format (Second Edition) ](https://www.w3.org/TR/rdf-sparql-XMLres/ ), [SPARQL 1.1 Query Results JSON Format ](https://www.w3.org/TR/sparql11-results-json/ ) and [SPARQL 1.1 Query Results CSV and TSV Formats ](https://www.w3.org/TR/sparql11-results-csv-tsv/ ).
Support for [SPARQL-star ](https://w3c.github.io/rdf-star/cg-spec/2021-12-17.html#query-result-formats ) is also available behind the `rdf-star` feature.
This crate is intended to be a building piece for SPARQL client and server implementations in Rust like [Oxigraph ](https://oxigraph.org ).
Usage example converting a JSON result file into a TSV result file:
```rust
use sparesults::{QueryResultsFormat, QueryResultsParser, QueryResultsReader, QueryResultsSerializer};
use std::io::Result;
fn convert_json_to_tsv(json_file: & [u8]) -> Result< Vec < u8 > > {
let json_parser = QueryResultsParser::from_format(QueryResultsFormat::Json);
let tsv_serializer = QueryResultsSerializer::from_format(QueryResultsFormat::Tsv);
// We start to read the JSON file and see which kind of results it is
match json_parser.read_results(json_file)? {
QueryResultsReader::Boolean(value) => {
// it's a boolean result, we copy it in TSV to the output buffer
tsv_serializer.write_boolean_result(Vec::new(), value)
},
QueryResultsReader::Solutions(solutions_reader) => {
// it's a set of solutions, we create a writer and we write to it while reading in streaming from the JSON file
let mut solutions_writer = tsv_serializer.solutions_writer(Vec::new(), solutions_reader.variables().to_vec())?;
for solution in solutions_reader {
solutions_writer.write(&solution?)?;
}
solutions_writer.finish()
}
}
}
// Let's test with a boolean
assert_eq!(
convert_json_to_tsv(b"{\"boolean\":true}".as_slice()).unwrap(),
b"true"
);
// And with a set of solutions
assert_eq!(
convert_json_to_tsv(b"{\"head\":{\"vars\":[\"foo\",\"bar\"]},\"results\":{\"bindings\":[{\"foo\":{\"type\":\"literal\",\"value\":\"test\"}}]}}".as_slice()).unwrap(),
b"?foo\t?bar\n\"test\"\t\n"
);
```
## License
This project is licensed under either of
* Apache License, Version 2.0, ([LICENSE-APACHE](../LICENSE-APACHE) or
`<http://www.apache.org/licenses/LICENSE-2.0>` )
* MIT license ([LICENSE-MIT](../LICENSE-MIT) or
`<http://opensource.org/licenses/MIT>` )
at your option.
### Contribution
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in Oxigraph by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.
