Struct QueryResultsSerializer

Source

pub struct QueryResultsSerializer { /* private fields */ }

Expand description

A serializer for SPARQL query results serialization formats.

It currently supports the following formats:

Example in JSON (the API is the same for XML, CSV and TSV):

use sparesults::{QueryResultsFormat, QueryResultsSerializer};
use oxrdf::{LiteralRef, Variable, VariableRef};
use std::iter::once;

let json_serializer = QueryResultsSerializer::from_format(QueryResultsFormat::Json);

// boolean
let mut buffer = Vec::new();
json_serializer.clone().serialize_boolean_to_writer(&mut buffer, true)?;
assert_eq!(buffer, br#"{"head":{},"boolean":true}"#);

// solutions
let mut buffer = Vec::new();
let mut serializer = json_serializer.serialize_solutions_to_writer(&mut buffer, vec![Variable::new("foo")?, Variable::new("bar")?])?;
serializer.serialize(once((VariableRef::new("foo")?, LiteralRef::from("test"))))?;
serializer.finish()?;
assert_eq!(buffer, br#"{"head":{"vars":["foo","bar"]},"results":{"bindings":[{"foo":{"type":"literal","value":"test"}}]}}"#);

Implementations§

Source §

impl QueryResultsSerializer

Source

pub fn from_format(format: QueryResultsFormat) -> QueryResultsSerializer

Builds a serializer for the given format.

Source

pub fn serialize_boolean_to_writer<W>( self, writer: W, value: bool, ) -> Result<W, Error>
where W: Write,

Write a boolean query result (from an ASK query) into the given Write implementation.

Example in XML (the API is the same for JSON, CSV and TSV):

use sparesults::{QueryResultsFormat, QueryResultsSerializer};

let xml_serializer = QueryResultsSerializer::from_format(QueryResultsFormat::Xml);
let mut buffer = Vec::new();
xml_serializer.serialize_boolean_to_writer(&mut buffer, true)?;
assert_eq!(buffer, br#"<?xml version="1.0"?><sparql xmlns="http://www.w3.org/2005/sparql-results#"><head></head><boolean>true</boolean></sparql>"#);

Source

pub fn write_boolean_result<W>( &self, writer: W, value: bool, ) -> Result<W, Error>
where W: Write,

👎Deprecated since 0.4.0: use serialize_boolean_to_writer

Source

pub fn serialize_solutions_to_writer<W>( self, writer: W, variables: Vec<Variable>, ) -> Result<WriterSolutionsSerializer<W>, Error>
where W: Write,

Returns a SolutionsSerializer allowing writing query solutions into the given Write implementation.

Do not forget to run the finish method to properly write the last bytes of the file.

This writer does unbuffered writes. You might want to use BufWriter to avoid that.

Example in XML (the API is the same for JSON, CSV and TSV):

use sparesults::{QueryResultsFormat, QueryResultsSerializer};
use oxrdf::{LiteralRef, Variable, VariableRef};
use std::iter::once;

let xml_serializer = QueryResultsSerializer::from_format(QueryResultsFormat::Xml);
let mut buffer = Vec::new();
let mut serializer = xml_serializer.serialize_solutions_to_writer(&mut buffer, vec![Variable::new("foo")?, Variable::new("bar")?])?;
serializer.serialize(once((VariableRef::new("foo")?, LiteralRef::from("test"))))?;
serializer.finish()?;
assert_eq!(buffer, br#"<?xml version="1.0"?><sparql xmlns="http://www.w3.org/2005/sparql-results#"><head><variable name="foo"/><variable name="bar"/></head><results><result><binding name="foo"><literal>test</literal></binding></result></results></sparql>"#);