quick_xml::reader

Struct NsReader

Source 
pub struct NsReader<R> { /* private fields */ }
Expand description

A low level encoding-agnostic XML event reader that performs namespace resolution.

Consumes a BufRead and streams XML Events.

Implementations§

Source§

impl<R: AsyncBufRead + Unpin> NsReader<R>

Source

pub async fn read_event_into_async<'b>( &mut self, buf: &'b mut Vec<u8>, ) -> Result<Event<'b>>

Available on crate feature async-tokio only.

An asynchronous version of read_event_into(). Reads the next event into given buffer.

This method manages namespaces but doesn’t resolve them automatically. You should call resolve_element() if you want to get a namespace.

You also can use read_resolved_event_into_async() instead if you want to resolve namespace as soon as you get an event.

§Examples
use quick_xml::events::Event;
use quick_xml::name::{Namespace, ResolveResult::*};
use quick_xml::reader::NsReader;

let mut reader = NsReader::from_reader(r#"
    <x:tag1 xmlns:x="www.xxxx" xmlns:y="www.yyyy" att1 = "test">
       <y:tag2><!--Test comment-->Test</y:tag2>
       <y:tag2>Test 2</y:tag2>
    </x:tag1>
"#.as_bytes());
reader.config_mut().trim_text(true);

let mut count = 0;
let mut buf = Vec::new();
let mut txt = Vec::new();
loop {
    match reader.read_event_into_async(&mut buf).await.unwrap() {
        Event::Start(e) => {
            count += 1;
            let (ns, local) = reader.resolve_element(e.name());
            match local.as_ref() {
                b"tag1" => assert_eq!(ns, Bound(Namespace(b"www.xxxx"))),
                b"tag2" => assert_eq!(ns, Bound(Namespace(b"www.yyyy"))),
                _ => unreachable!(),
            }
        }
        Event::Text(e) => {
            txt.push(e.unescape().unwrap().into_owned())
        }
        Event::Eof => break,
        _ => (),
    }
    buf.clear();
}
assert_eq!(count, 3);
assert_eq!(txt, vec!["Test".to_string(), "Test 2".to_string()]);
Source

pub async fn read_to_end_into_async<'n>( &mut self, end: QName<'n>, buf: &mut Vec<u8>, ) -> Result<Span>

Available on crate feature async-tokio only.

An asynchronous version of read_to_end_into(). Reads asynchronously until end element is found using provided buffer as intermediate storage for events content. This function is supposed to be called after you already read a Start event.

See the documentation of read_to_end_into() for more information.

§Examples

This example shows, how you can skip XML content after you read the start event.

use quick_xml::name::{Namespace, ResolveResult};
use quick_xml::events::{BytesStart, Event};
use quick_xml::reader::NsReader;

let mut reader = NsReader::from_reader(r#"
    <outer xmlns="namespace 1">
        <inner xmlns="namespace 2">
            <outer></outer>
        </inner>
        <inner>
            <inner></inner>
            <inner/>
            <outer></outer>
            <p:outer xmlns:p="ns"></p:outer>
            <outer/>
        </inner>
    </outer>
"#.as_bytes());
reader.config_mut().trim_text(true);
let mut buf = Vec::new();

let ns = Namespace(b"namespace 1");
let start = BytesStart::from_content(r#"outer xmlns="namespace 1""#, 5);
let end   = start.to_end().into_owned();

// First, we read a start event...
assert_eq!(
    reader.read_resolved_event_into_async(&mut buf).await.unwrap(),
    (ResolveResult::Bound(ns), Event::Start(start))
);

// ...then, we could skip all events to the corresponding end event.
// This call will correctly handle nested <outer> elements.
// Note, however, that this method does not handle namespaces.
reader.read_to_end_into_async(end.name(), &mut buf).await.unwrap();

// At the end we should get an Eof event, because we ate the whole XML
assert_eq!(
    reader.read_resolved_event_into_async(&mut buf).await.unwrap(),
    (ResolveResult::Unbound, Event::Eof)
);
Source

pub async fn read_resolved_event_into_async<'ns, 'b>( &'ns mut self, buf: &'b mut Vec<u8>, ) -> Result<(ResolveResult<'ns>, Event<'b>)>

Available on crate feature async-tokio only.

An asynchronous version of read_resolved_event_into(). Reads the next event into given buffer asynchronously and resolves its namespace (if applicable).

Namespace is resolved only for Start, Empty and End events. For all other events the concept of namespace is not defined, so a ResolveResult::Unbound is returned.

If you are not interested in namespaces, you can use read_event_into_async() which will not automatically resolve namespaces for you.

§Examples
use quick_xml::events::Event;
use quick_xml::name::{Namespace, QName, ResolveResult::*};
use quick_xml::reader::NsReader;

let mut reader = NsReader::from_reader(r#"
    <x:tag1 xmlns:x="www.xxxx" xmlns:y="www.yyyy" att1 = "test">
       <y:tag2><!--Test comment-->Test</y:tag2>
       <y:tag2>Test 2</y:tag2>
    </x:tag1>
"#.as_bytes());
reader.config_mut().trim_text(true);

let mut count = 0;
let mut buf = Vec::new();
let mut txt = Vec::new();
loop {
    match reader.read_resolved_event_into_async(&mut buf).await.unwrap() {
        (Bound(Namespace(b"www.xxxx")), Event::Start(e)) => {
            count += 1;
            assert_eq!(e.local_name(), QName(b"tag1").into());
        }
        (Bound(Namespace(b"www.yyyy")), Event::Start(e)) => {
            count += 1;
            assert_eq!(e.local_name(), QName(b"tag2").into());
        }
        (_, Event::Start(_)) => unreachable!(),

        (_, Event::Text(e)) => {
            txt.push(e.unescape().unwrap().into_owned())
        }
        (_, Event::Eof) => break,
        _ => (),
    }
    buf.clear();
}
assert_eq!(count, 3);
assert_eq!(txt, vec!["Test".to_string(), "Test 2".to_string()]);
Source§

impl<R> NsReader<R>

Builder methods

Source

pub fn from_reader(reader: R) -> Self

Creates a NsReader that reads from a reader.

Source

pub const fn config(&self) -> &Config

Returns reference to the parser configuration

Source

pub fn config_mut(&mut self) -> &mut Config

Returns mutable reference to the parser configuration

Source

pub const fn prefixes(&self) -> PrefixIter<'_> ⓘ

Returns all the prefixes currently declared except the default xml and xmlns namespaces.

§Examples

This example shows what results the returned iterator would return after reading each event of a simple XML.

use quick_xml::name::{Namespace, PrefixDeclaration};
use quick_xml::NsReader;

let src = "<root>
  <a xmlns=\"a1\" xmlns:a=\"a2\">
    <b xmlns=\"b1\" xmlns:b=\"b2\">
      <c/>
    </b>
    <d/>
  </a>
</root>";
let mut reader = NsReader::from_str(src);
reader.config_mut().trim_text(true);
// No prefixes at the beginning
assert_eq!(reader.prefixes().collect::<Vec<_>>(), vec![]);

reader.read_resolved_event()?; // <root>
// No prefixes declared on root
assert_eq!(reader.prefixes().collect::<Vec<_>>(), vec![]);

reader.read_resolved_event()?; // <a>
// Two prefixes declared on "a"
assert_eq!(reader.prefixes().collect::<Vec<_>>(), vec![
    (PrefixDeclaration::Default, Namespace(b"a1")),
    (PrefixDeclaration::Named(b"a"), Namespace(b"a2"))
]);

reader.read_resolved_event()?; // <b>
// The default prefix got overridden and new "b" prefix
assert_eq!(reader.prefixes().collect::<Vec<_>>(), vec![
    (PrefixDeclaration::Named(b"a"), Namespace(b"a2")),
    (PrefixDeclaration::Default, Namespace(b"b1")),
    (PrefixDeclaration::Named(b"b"), Namespace(b"b2"))
]);

reader.read_resolved_event()?; // <c/>
// Still the same
assert_eq!(reader.prefixes().collect::<Vec<_>>(), vec![
    (PrefixDeclaration::Named(b"a"), Namespace(b"a2")),
    (PrefixDeclaration::Default, Namespace(b"b1")),
    (PrefixDeclaration::Named(b"b"), Namespace(b"b2"))
]);

reader.read_resolved_event()?; // </b>
// Still the same
assert_eq!(reader.prefixes().collect::<Vec<_>>(), vec![
    (PrefixDeclaration::Named(b"a"), Namespace(b"a2")),
    (PrefixDeclaration::Default, Namespace(b"b1")),
    (PrefixDeclaration::Named(b"b"), Namespace(b"b2"))
]);

reader.read_resolved_event()?; // <d/>
// </b> got closed so back to the prefixes declared on <a>
assert_eq!(reader.prefixes().collect::<Vec<_>>(), vec![
    (PrefixDeclaration::Default, Namespace(b"a1")),
    (PrefixDeclaration::Named(b"a"), Namespace(b"a2"))
]);

reader.read_resolved_event()?; // </a>
// Still the same
assert_eq!(reader.prefixes().collect::<Vec<_>>(), vec![
    (PrefixDeclaration::Default, Namespace(b"a1")),
    (PrefixDeclaration::Named(b"a"), Namespace(b"a2"))
]);

reader.read_resolved_event()?; // </root>
// <a> got closed
assert_eq!(reader.prefixes().collect::<Vec<_>>(), vec![]);
Source§

impl<R> NsReader<R>

Getters

Source

pub fn into_inner(self) -> R

Consumes NsReader returning the underlying reader

See the Reader::into_inner for examples

Source

pub fn get_mut(&mut self) -> &mut R

Gets a mutable reference to the underlying reader.

Source

pub fn resolve<'n>( &self, name: QName<'n>, attribute: bool, ) -> (ResolveResult<'_>, LocalName<'n>)

Resolves a potentially qualified element name or attribute name into (namespace name, local name).

Qualified names have the form prefix:local-name where the prefix is defined on any containing XML element via xmlns:prefix="the:namespace:uri". The namespace prefix can be defined on the same element as the name in question.

The method returns following results depending on the name shape, attribute flag and the presence of the default namespace:

attributexmlns="..."QNameResolveResultLocalName
trueNot definedlocal-nameUnboundlocal-name
trueDefinedlocal-nameUnboundlocal-name
trueanyprefix:local-nameBound / Unknownlocal-name
falseNot definedlocal-nameUnboundlocal-name
falseDefinedlocal-nameBound (default)local-name
falseanyprefix:local-nameBound / Unknownlocal-name

If you want to clearly indicate that name that you resolve is an element or an attribute name, you could use resolve_attribute() or resolve_element() methods.

§Lifetimes
  • 'n: lifetime of a name. Returned local name will be bound to the same lifetime as the name in question.
  • returned namespace name will be bound to the reader itself
Source

pub fn resolve_element<'n>( &self, name: QName<'n>, ) -> (ResolveResult<'_>, LocalName<'n>)

Resolves a potentially qualified element name into (namespace name, local name).

Qualified element names have the form prefix:local-name where the prefix is defined on any containing XML element via xmlns:prefix="the:namespace:uri". The namespace prefix can be defined on the same element as the element in question.

Unqualified elements inherits the current default namespace.

The method returns following results depending on the name shape and the presence of the default namespace:

xmlns="..."QNameResolveResultLocalName
Not definedlocal-nameUnboundlocal-name
Definedlocal-nameBound (default)local-name
anyprefix:local-nameBound / Unknownlocal-name
§Lifetimes
  • 'n: lifetime of an element name. Returned local name will be bound to the same lifetime as the name in question.
  • returned namespace name will be bound to the reader itself
§Examples

This example shows how you can resolve qualified name into a namespace. Note, that in the code like this you do not need to do that manually, because the namespace resolution result returned by the read_resolved_event().

use quick_xml::events::Event;
use quick_xml::name::{Namespace, QName, ResolveResult::*};
use quick_xml::reader::NsReader;

let mut reader = NsReader::from_str("<tag xmlns='root namespace'/>");

match reader.read_event().unwrap() {
    Event::Empty(e) => assert_eq!(
        reader.resolve_element(e.name()),
        (Bound(Namespace(b"root namespace")), QName(b"tag").into())
    ),
    _ => unreachable!(),
}
Source

pub fn resolve_attribute<'n>( &self, name: QName<'n>, ) -> (ResolveResult<'_>, LocalName<'n>)

Resolves a potentially qualified attribute name into (namespace name, local name).

Qualified attribute names have the form prefix:local-name where the prefix is defined on any containing XML element via xmlns:prefix="the:namespace:uri". The namespace prefix can be defined on the same element as the attribute in question.

Unqualified attribute names do not inherit the current default namespace.

The method returns following results depending on the name shape and the presence of the default namespace:

xmlns="..."QNameResolveResultLocalName
Not definedlocal-nameUnboundlocal-name
Definedlocal-nameUnboundlocal-name
anyprefix:local-nameBound / Unknownlocal-name
§Lifetimes
  • 'n: lifetime of an attribute name. Returned local name will be bound to the same lifetime as the name in question.
  • returned namespace name will be bound to the reader itself
§Examples
use quick_xml::events::Event;
use quick_xml::name::{Namespace, QName, ResolveResult::*};
use quick_xml::reader::NsReader;

let mut reader = NsReader::from_str("
    <tag one='1'
         p:two='2'
         xmlns='root namespace'
         xmlns:p='other namespace'/>
");
reader.config_mut().trim_text(true);

match reader.read_event().unwrap() {
    Event::Empty(e) => {
        let mut iter = e.attributes();

        // Unlike elements, attributes without explicit namespace
        // not bound to any namespace
        let one = iter.next().unwrap().unwrap();
        assert_eq!(
            reader.resolve_attribute(one.key),
            (Unbound, QName(b"one").into())
        );

        let two = iter.next().unwrap().unwrap();
        assert_eq!(
            reader.resolve_attribute(two.key),
            (Bound(Namespace(b"other namespace")), QName(b"two").into())
        );
    }
    _ => unreachable!(),
}
Source§

impl<R: BufRead> NsReader<R>

Source

pub fn read_event_into<'b>(&mut self, buf: &'b mut Vec<u8>) -> Result<Event<'b>>

Reads the next event into given buffer.

This method manages namespaces but doesn’t resolve them automatically. You should call resolve_element() if you want to get a namespace.

You also can use read_resolved_event_into() instead if you want to resolve namespace as soon as you get an event.

§Examples
use quick_xml::events::Event;
use quick_xml::name::{Namespace, ResolveResult::*};
use quick_xml::reader::NsReader;

let mut reader = NsReader::from_str(r#"
    <x:tag1 xmlns:x="www.xxxx" xmlns:y="www.yyyy" att1 = "test">
       <y:tag2><!--Test comment-->Test</y:tag2>
       <y:tag2>Test 2</y:tag2>
    </x:tag1>
"#);
reader.config_mut().trim_text(true);

let mut count = 0;
let mut buf = Vec::new();
let mut txt = Vec::new();
loop {
    match reader.read_event_into(&mut buf).unwrap() {
        Event::Start(e) => {
            count += 1;
            let (ns, local) = reader.resolve_element(e.name());
            match local.as_ref() {
                b"tag1" => assert_eq!(ns, Bound(Namespace(b"www.xxxx"))),
                b"tag2" => assert_eq!(ns, Bound(Namespace(b"www.yyyy"))),
                _ => unreachable!(),
            }
        }
        Event::Text(e) => {
            txt.push(e.unescape().unwrap().into_owned())
        }
        Event::Eof => break,
        _ => (),
    }
    buf.clear();
}
assert_eq!(count, 3);
assert_eq!(txt, vec!["Test".to_string(), "Test 2".to_string()]);
Source

pub fn read_resolved_event_into<'b>( &mut self, buf: &'b mut Vec<u8>, ) -> Result<(ResolveResult<'_>, Event<'b>)>

Reads the next event into given buffer and resolves its namespace (if applicable).

Namespace is resolved only for Start, Empty and End events. For all other events the concept of namespace is not defined, so a ResolveResult::Unbound is returned.

If you are not interested in namespaces, you can use read_event_into() which will not automatically resolve namespaces for you.

§Examples
use quick_xml::events::Event;
use quick_xml::name::{Namespace, QName, ResolveResult::*};
use quick_xml::reader::NsReader;

let mut reader = NsReader::from_str(r#"
    <x:tag1 xmlns:x="www.xxxx" xmlns:y="www.yyyy" att1 = "test">
       <y:tag2><!--Test comment-->Test</y:tag2>
       <y:tag2>Test 2</y:tag2>
    </x:tag1>
"#);
reader.config_mut().trim_text(true);

let mut count = 0;
let mut buf = Vec::new();
let mut txt = Vec::new();
loop {
    match reader.read_resolved_event_into(&mut buf).unwrap() {
        (Bound(Namespace(b"www.xxxx")), Event::Start(e)) => {
            count += 1;
            assert_eq!(e.local_name(), QName(b"tag1").into());
        }
        (Bound(Namespace(b"www.yyyy")), Event::Start(e)) => {
            count += 1;
            assert_eq!(e.local_name(), QName(b"tag2").into());
        }
        (_, Event::Start(_)) => unreachable!(),

        (_, Event::Text(e)) => {
            txt.push(e.unescape().unwrap().into_owned())
        }
        (_, Event::Eof) => break,
        _ => (),
    }
    buf.clear();
}
assert_eq!(count, 3);
assert_eq!(txt, vec!["Test".to_string(), "Test 2".to_string()]);
Source

pub fn read_to_end_into( &mut self, end: QName<'_>, buf: &mut Vec<u8>, ) -> Result<Span>

Reads until end element is found using provided buffer as intermediate storage for events content. This function is supposed to be called after you already read a Start event.

Returns a span that cover content between > of an opening tag and < of a closing tag or an empty slice, if expand_empty_elements is set and this method was called after reading expanded Start event.

Manages nested cases where parent and child elements have the literally same name.

If a corresponding End event is not found, an error of type IllFormed will be returned. In particularly, that error will be returned if you call this method without consuming the corresponding Start event first.

If your reader created from a string slice or byte array slice, it is better to use read_to_end() method, because it will not copy bytes into intermediate buffer.

The provided buf buffer will be filled only by one event content at time. Before reading of each event the buffer will be cleared. If you know an appropriate size of each event, you can preallocate the buffer to reduce number of reallocations.

The end parameter should contain name of the end element in the reader encoding. It is good practice to always get that parameter using BytesStart::to_end() method.

§Namespaces

While the NsReader does namespace resolution, namespaces does not change the algorithm for comparing names. Although the names a:name and b:name where both prefixes a and b resolves to the same namespace, are semantically equivalent, </b:name> cannot close <a:name>, because according to the specification

The end of every element that begins with a start-tag MUST be marked by an end-tag containing a name that echoes the element’s type as given in the start-tag

§Examples

This example shows, how you can skip XML content after you read the start event.

use quick_xml::events::{BytesStart, Event};
use quick_xml::name::{Namespace, ResolveResult};
use quick_xml::reader::NsReader;

let mut reader = NsReader::from_str(r#"
    <outer xmlns="namespace 1">
        <inner xmlns="namespace 2">
            <outer></outer>
        </inner>
        <inner>
            <inner></inner>
            <inner/>
            <outer></outer>
            <p:outer xmlns:p="ns"></p:outer>
            <outer/>
        </inner>
    </outer>
"#);
reader.config_mut().trim_text(true);
let mut buf = Vec::new();

let ns = Namespace(b"namespace 1");
let start = BytesStart::from_content(r#"outer xmlns="namespace 1""#, 5);
let end   = start.to_end().into_owned();

// First, we read a start event...
assert_eq!(
    reader.read_resolved_event_into(&mut buf).unwrap(),
    (ResolveResult::Bound(ns), Event::Start(start))
);

// ...then, we could skip all events to the corresponding end event.
// This call will correctly handle nested <outer> elements.
// Note, however, that this method does not handle namespaces.
reader.read_to_end_into(end.name(), &mut buf).unwrap();

// At the end we should get an Eof event, because we ate the whole XML
assert_eq!(
    reader.read_resolved_event_into(&mut buf).unwrap(),
    (ResolveResult::Unbound, Event::Eof)
);
Source§

impl NsReader<BufReader<File>>

Source

pub fn from_file<P: AsRef<Path>>(path: P) -> Result<Self>

Creates an XML reader from a file path.

Source§

impl<'i> NsReader<&'i [u8]>

Source

pub fn from_str(s: &'i str) -> Self

Creates an XML reader from a string slice.

Source

pub fn read_event(&mut self) -> Result<Event<'i>>

Reads the next event, borrow its content from the input buffer.

This method manages namespaces but doesn’t resolve them automatically. You should call resolve_element() if you want to get a namespace.

You also can use read_resolved_event() instead if you want to resolve namespace as soon as you get an event.

There is no asynchronous read_event_async() version of this function, because it is not necessary – the contents are already in memory and no IO is needed, therefore there is no potential for blocking.

§Examples
use quick_xml::events::Event;
use quick_xml::name::{Namespace, ResolveResult::*};
use quick_xml::reader::NsReader;

let mut reader = NsReader::from_str(r#"
    <x:tag1 xmlns:x="www.xxxx" xmlns:y="www.yyyy" att1 = "test">
       <y:tag2><!--Test comment-->Test</y:tag2>
       <y:tag2>Test 2</y:tag2>
    </x:tag1>
"#);
reader.config_mut().trim_text(true);

let mut count = 0;
let mut txt = Vec::new();
loop {
    match reader.read_event().unwrap() {
        Event::Start(e) => {
            count += 1;
            let (ns, local) = reader.resolve_element(e.name());
            match local.as_ref() {
                b"tag1" => assert_eq!(ns, Bound(Namespace(b"www.xxxx"))),
                b"tag2" => assert_eq!(ns, Bound(Namespace(b"www.yyyy"))),
                _ => unreachable!(),
            }
        }
        Event::Text(e) => {
            txt.push(e.unescape().unwrap().into_owned())
        }
        Event::Eof => break,
        _ => (),
    }
}
assert_eq!(count, 3);
assert_eq!(txt, vec!["Test".to_string(), "Test 2".to_string()]);
Source

pub fn read_resolved_event(&mut self) -> Result<(ResolveResult<'_>, Event<'i>)>

Reads the next event, borrow its content from the input buffer, and resolves its namespace (if applicable).

Namespace is resolved only for Start, Empty and End events. For all other events the concept of namespace is not defined, so a ResolveResult::Unbound is returned.

If you are not interested in namespaces, you can use read_event() which will not automatically resolve namespaces for you.

There is no asynchronous read_resolved_event_async() version of this function, because it is not necessary – the contents are already in memory and no IO is needed, therefore there is no potential for blocking.

§Examples
use quick_xml::events::Event;
use quick_xml::name::{Namespace, QName, ResolveResult::*};
use quick_xml::reader::NsReader;

let mut reader = NsReader::from_str(r#"
    <x:tag1 xmlns:x="www.xxxx" xmlns:y="www.yyyy" att1 = "test">
       <y:tag2><!--Test comment-->Test</y:tag2>
       <y:tag2>Test 2</y:tag2>
    </x:tag1>
"#);
reader.config_mut().trim_text(true);

let mut count = 0;
let mut txt = Vec::new();
loop {
    match reader.read_resolved_event().unwrap() {
        (Bound(Namespace(b"www.xxxx")), Event::Start(e)) => {
            count += 1;
            assert_eq!(e.local_name(), QName(b"tag1").into());
        }
        (Bound(Namespace(b"www.yyyy")), Event::Start(e)) => {
            count += 1;
            assert_eq!(e.local_name(), QName(b"tag2").into());
        }
        (_, Event::Start(_)) => unreachable!(),

        (_, Event::Text(e)) => {
            txt.push(e.unescape().unwrap().into_owned())
        }
        (_, Event::Eof) => break,
        _ => (),
    }
}
assert_eq!(count, 3);
assert_eq!(txt, vec!["Test".to_string(), "Test 2".to_string()]);
Source

pub fn read_to_end(&mut self, end: QName<'_>) -> Result<Span>

Reads until end element is found. This function is supposed to be called after you already read a Start event.

Returns a span that cover content between > of an opening tag and < of a closing tag or an empty slice, if expand_empty_elements is set and this method was called after reading expanded Start event.

Manages nested cases where parent and child elements have the literally same name.

If a corresponding End event is not found, an error of type IllFormed will be returned. In particularly, that error will be returned if you call this method without consuming the corresponding Start event first.

The end parameter should contain name of the end element in the reader encoding. It is good practice to always get that parameter using BytesStart::to_end() method.

There is no asynchronous read_to_end_async() version of this function, because it is not necessary – the contents are already in memory and no IO is needed, therefore there is no potential for blocking.

§Namespaces

While the NsReader does namespace resolution, namespaces does not change the algorithm for comparing names. Although the names a:name and b:name where both prefixes a and b resolves to the same namespace, are semantically equivalent, </b:name> cannot close <a:name>, because according to the specification

The end of every element that begins with a start-tag MUST be marked by an end-tag containing a name that echoes the element’s type as given in the start-tag

§Examples

This example shows, how you can skip XML content after you read the start event.

use quick_xml::events::{BytesStart, Event};
use quick_xml::name::{Namespace, ResolveResult};
use quick_xml::reader::NsReader;

let mut reader = NsReader::from_str(r#"
    <outer xmlns="namespace 1">
        <inner xmlns="namespace 2">
            <outer></outer>
        </inner>
        <inner>
            <inner></inner>
            <inner/>
            <outer></outer>
            <p:outer xmlns:p="ns"></p:outer>
            <outer/>
        </inner>
    </outer>
"#);
reader.config_mut().trim_text(true);

let ns = Namespace(b"namespace 1");
let start = BytesStart::from_content(r#"outer xmlns="namespace 1""#, 5);
let end   = start.to_end().into_owned();

// First, we read a start event...
assert_eq!(
    reader.read_resolved_event().unwrap(),
    (ResolveResult::Bound(ns), Event::Start(start))
);

// ...then, we could skip all events to the corresponding end event.
// This call will correctly handle nested <outer> elements.
// Note, however, that this method does not handle namespaces.
reader.read_to_end(end.name()).unwrap();

// At the end we should get an Eof event, because we ate the whole XML
assert_eq!(
    reader.read_resolved_event().unwrap(),
    (ResolveResult::Unbound, Event::Eof)
);
Source

pub fn read_text(&mut self, end: QName<'_>) -> Result<Cow<'i, str>>

Reads content between start and end tags, including any markup. This function is supposed to be called after you already read a Start event.

Manages nested cases where parent and child elements have the literally same name.

This method does not unescape read data, instead it returns content “as is” of the XML document. This is because it has no idea what text it reads, and if, for example, it contains CDATA section, attempt to unescape it content will spoil data.

Any text will be decoded using the XML current decoder().

Actually, this method perform the following code:

ⓘ
let span = reader.read_to_end(end)?;
let text = reader.decoder().decode(&reader.inner_slice[span]);
§Examples

This example shows, how you can read a HTML content from your XML document.

use quick_xml::events::{BytesStart, Event};
use quick_xml::reader::NsReader;

let mut reader = NsReader::from_str(r#"
    <html>
        <title>This is a HTML text</title>
        <p>Usual XML rules does not apply inside it
        <p>For example, elements not needed to be &quot;closed&quot;
    </html>
"#);
reader.config_mut().trim_text(true);

let start = BytesStart::new("html");
let end   = start.to_end().into_owned();

// First, we read a start event...
assert_eq!(reader.read_event().unwrap(), Event::Start(start));
// ...and disable checking of end names because we expect HTML further...
reader.config_mut().check_end_names = false;

// ...then, we could read text content until close tag.
// This call will correctly handle nested <html> elements.
let text = reader.read_text(end.name()).unwrap();
assert_eq!(text, Cow::Borrowed(r#"
        <title>This is a HTML text</title>
        <p>Usual XML rules does not apply inside it
        <p>For example, elements not needed to be &quot;closed&quot;
    "#));

// Now we can enable checks again
reader.config_mut().check_end_names = true;

// At the end we should get an Eof event, because we ate the whole XML
assert_eq!(reader.read_event().unwrap(), Event::Eof);

Methods from Deref<Target = Reader<R>>§

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pub fn config(&self) -> &Config

Returns reference to the parser configuration

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pub fn get_ref(&self) -> &R

Gets a reference to the underlying reader.

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pub fn buffer_position(&self) -> u64

Gets the current byte position in the input data.

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pub fn error_position(&self) -> u64

Gets the last error byte position in the input data. If there is no errors yet, returns 0.

Unlike buffer_position it will point to the place where it is rational to report error to the end user. For example, all SyntaxErrors are reported when the parser sees EOF inside of some kind of markup. The buffer_position() will point to the last byte of input which is not very useful. error_position() will point to the start of corresponding markup element (i. e. to the < character).

This position is always <= buffer_position().

Source

pub fn decoder(&self) -> Decoder

Get the decoder, used to decode bytes, read by this reader, to the strings.

If encoding feature is enabled, the used encoding may change after parsing the XML declaration, otherwise encoding is fixed to UTF-8.

If encoding feature is enabled and no encoding is specified in declaration, defaults to UTF-8.

Trait Implementations§

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impl<R> Deref for NsReader<R>

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type Target = Reader<R>

The resulting type after dereferencing.
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fn deref(&self) -> &Self::Target

Dereferences the value.

Auto Trait Implementations§

§

impl<R> Freeze for NsReader<R>
where R: Freeze,

§

impl<R> RefUnwindSafe for NsReader<R>
where R: RefUnwindSafe,

§

impl<R> Send for NsReader<R>
where R: Send,

§

impl<R> Sync for NsReader<R>
where R: Sync,

§

impl<R> Unpin for NsReader<R>
where R: Unpin,

§

impl<R> UnwindSafe for NsReader<R>
where R: UnwindSafe,

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<P, T> Receiver for P
where P: Deref<Target = T> + ?Sized, T: ?Sized,

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type Target = T

🔬This is a nightly-only experimental API. (arbitrary_self_types)
Available on non-bootstrap only.
The target type on which the method may be called.
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.