Expand description
Utilities to read and write RDF results formats using sparesults.
It supports SPARQL Query Results XML Format (Second Edition), SPARQL 1.1 Query Results JSON Format and SPARQL 1.1 Query Results CSV and TSV Formats.
Usage example converting a JSON result file into a TSV result file:
use oxigraph::sparql::results::{QueryResultsFormat, QueryResultsParser, ReaderQueryResultsParserOutput, 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.for_reader(json_file)? {
ReaderQueryResultsParserOutput::Boolean(value) => {
// it's a boolean result, we copy it in TSV to the output buffer
tsv_serializer.serialize_boolean_to_writer(Vec::new(), value)
}
ReaderQueryResultsParserOutput::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 tsv_solutions_serializer = tsv_serializer.serialize_solutions_to_writer(Vec::new(), solutions_reader.variables().to_vec())?;
for solution in solutions_reader {
tsv_solutions_serializer.serialize(&solution?)?;
}
tsv_solutions_serializer.finish()
}
}
}
// Let's test with a boolean
assert_eq!(
convert_json_to_tsv(br#"{"boolean":true}"#.as_slice()).unwrap(),
b"true"
);
// And with a set of solutions
assert_eq!(
convert_json_to_tsv(br#"{"head":{"vars":["foo","bar"]},"results":{"bindings":[{"foo":{"type":"literal","value":"test"}}]}}"#.as_slice()).unwrap(),
b"?foo\t?bar\n\"test\"\t\n"
);
Modules§
- Definition of
QuerySolution
structure and associated utility constructions.
Structs§
- Parsers for SPARQL query results serialization formats.
- A serializer for SPARQL query results serialization formats.
- An error in the syntax of the parsed file.
- Tuple associating variables and terms that are the result of a SPARQL query.
- A streaming parser of a set of
QuerySolution
solutions. - A streaming parser of a set of
QuerySolution
solutions. - A position in a text i.e. a
line
number starting from 0, acolumn
number starting from 0 (in number of code points) and a global fileoffset
starting from 0 (in number of bytes). - Allows writing query results into a
Write
implementation.
Enums§
- SPARQL query results serialization formats.
- Error returned during SPARQL result formats format parsing.
- The reader for a given read of a results file.
- The reader for a given read of a results file.