Struct rio_xml::RdfXmlParser

pub struct RdfXmlParser<R: BufRead> { /* private fields */ }

A RDF/XML streaming parser.

It implements the TriplesParser trait. It reads the file in streaming. It does not keep data in memory except a stack for handling nested XML tags, and a set of all seen rdf:IDs to detect duplicate ids and fail according to the specification.

Its performances are not optimized yet and hopefully could be significantly enhanced by reducing the number of allocations and copies done by the parser.

Count the number of people using the TriplesParser API without proper error management:

use rio_xml::{RdfXmlParser, RdfXmlError};
use rio_api::parser::TriplesParser;
use rio_api::model::NamedNode;

let file = b"<?xml version=\"1.0\"?>
<rdf:RDF xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\" xmlns:schema=\"http://schema.org/\">
 <rdf:Description rdf:about=\"http://example.com/foo\">
   <rdf:type rdf:resource=\"http://schema.org/Person\" />
   <schema:name>Foo</schema:name>
 </rdf:Description>
 <schema:Person rdf:about=\"http://example.com/bar\" schema:name=\"Bar\" />
</rdf:RDF>";

let rdf_type = NamedNode { iri: "http://www.w3.org/1999/02/22-rdf-syntax-ns#type" };
let schema_person = NamedNode { iri: "http://schema.org/Person" };
let mut count = 0;
RdfXmlParser::new(file.as_ref(), None).parse_all(&mut |t| {
    if t.predicate == rdf_type && t.object == schema_person.into() {
        count += 1;
    }
    Ok(()) as Result<(), RdfXmlError>
})?;
assert_eq!(2, count);

Implementations

impl<R: BufRead> RdfXmlParser<R>

pub fn new(reader: R, base_iri: Option<Iri<String>>) -> Self

Builds the parser from a BufRead implementation, and a base IRI for relative IRI resolution.

pub fn buffer_position(&self) -> usize

The current byte position in the input data.

Trait Implementations

impl<R: BufRead> TriplesParser for RdfXmlParser<R>

type Error = RdfXmlError

fn parse_step<E: From<RdfXmlError>>(
    &mut self,
    on_triple: &mut impl FnMut(Triple<'_>) -> Result<(), E>
) -> Result<(), E>

Parses a small chunk of the file and calls on_triple each time a new triple is read. (A “small chunk” could be a line for an N-Triples parser.)

fn is_end(&self) -> bool

Returns true if the file has been completely consumed by the parser.

fn parse_all<E>(
    &mut self,
    on_triple: &mut impl FnMut(Triple<'_>) -> Result<(), E>
) -> Result<(), E> where
    E: From<Self::Error>, 

Parses the complete file and calls on_triple each time a new triple is read.

fn into_iter<T, E, F>(
    self,
    convert_triple: F
) -> TriplesParserIterator<T, E, F, Self> where
    E: From<Self::Error>,
    F: FnMut(Triple<'_>) -> Result<T, E>, 

Converts the parser into a Result<T, E> iterator.