quick_xml/writer/async_tokio.rs
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use std::future::Future;
use std::result::Result as StdResult;
use tokio::io::{AsyncWrite, AsyncWriteExt};
use crate::errors::{Error, Result};
use crate::events::{BytesCData, BytesPI, BytesText, Event};
use crate::{ElementWriter, Writer};
impl<W: AsyncWrite + Unpin> Writer<W> {
/// Writes the given event to the underlying writer. Async version of [`Writer::write_event`].
pub async fn write_event_async<'a, E: Into<Event<'a>>>(&mut self, event: E) -> Result<()> {
let mut next_should_line_break = true;
let result = match event.into() {
Event::Start(e) => {
let result = self.write_wrapped_async(b"<", &e, b">").await;
if let Some(i) = self.indent.as_mut() {
i.grow();
}
result
}
Event::End(e) => {
if let Some(i) = self.indent.as_mut() {
i.shrink();
}
self.write_wrapped_async(b"</", &e, b">").await
}
Event::Empty(e) => self.write_wrapped_async(b"<", &e, b"/>").await,
Event::Text(e) => {
next_should_line_break = false;
self.write_async(&e).await
}
Event::Comment(e) => self.write_wrapped_async(b"<!--", &e, b"-->").await,
Event::CData(e) => {
next_should_line_break = false;
self.write_async(b"<![CDATA[").await?;
self.write_async(&e).await?;
self.write_async(b"]]>").await
}
Event::Decl(e) => self.write_wrapped_async(b"<?", &e, b"?>").await,
Event::PI(e) => self.write_wrapped_async(b"<?", &e, b"?>").await,
Event::DocType(e) => self.write_wrapped_async(b"<!DOCTYPE ", &e, b">").await,
Event::Eof => Ok(()),
};
if let Some(i) = self.indent.as_mut() {
i.should_line_break = next_should_line_break;
}
result
}
/// Manually write a newline and indentation at the proper level. Async version of
/// [`Writer::write_indent`].
///
/// This method will do nothing if `Writer` was not constructed with [`Writer::new_with_indent`].
pub async fn write_indent_async(&mut self) -> Result<()> {
if let Some(ref i) = self.indent {
self.writer.write_all(b"\n").await?;
self.writer.write_all(i.current()).await?;
}
Ok(())
}
#[inline]
async fn write_async(&mut self, value: &[u8]) -> Result<()> {
self.writer.write_all(value).await.map_err(Into::into)
}
#[inline]
async fn write_wrapped_async(
&mut self,
before: &[u8],
value: &[u8],
after: &[u8],
) -> Result<()> {
if let Some(ref i) = self.indent {
if i.should_line_break {
self.writer.write_all(b"\n").await?;
self.writer.write_all(i.current()).await?;
}
}
self.write_async(before).await?;
self.write_async(value).await?;
self.write_async(after).await?;
Ok(())
}
}
impl<'a, W: AsyncWrite + Unpin> ElementWriter<'a, W> {
/// Write some text inside the current element.
///
/// # Example
///
/// ```
/// # use quick_xml::writer::Writer;
/// # use quick_xml::events::BytesText;
/// # use tokio::io::AsyncWriteExt;
/// # #[tokio::main(flavor = "current_thread")] async fn main() {
/// let mut buffer = Vec::new();
/// let mut tokio_buffer = tokio::io::BufWriter::new(&mut buffer);
/// let mut writer = Writer::new_with_indent(&mut tokio_buffer, b' ', 4);
///
/// writer
/// .create_element("paired")
/// .with_attribute(("attr1", "value1"))
/// .with_attribute(("attr2", "value2"))
/// .write_text_content_async(BytesText::new("text"))
/// .await
/// .expect("cannot write content");
///
/// tokio_buffer.flush().await.expect("flush failed");
///
/// assert_eq!(
/// std::str::from_utf8(&buffer).unwrap(),
/// r#"<paired attr1="value1" attr2="value2">text</paired>"#
/// );
/// # }
pub async fn write_text_content_async(self, text: BytesText<'_>) -> Result<&'a mut Writer<W>> {
self.writer
.write_event_async(Event::Start(self.start_tag.borrow()))
.await?;
self.writer.write_event_async(Event::Text(text)).await?;
self.writer
.write_event_async(Event::End(self.start_tag.to_end()))
.await?;
Ok(self.writer)
}
/// Write a CData event `<![CDATA[...]]>` inside the current element.
///
/// # Example
///
/// ```
/// # use quick_xml::writer::Writer;
/// # use quick_xml::events::BytesCData;
/// # use tokio::io::AsyncWriteExt;
/// # #[tokio::main(flavor = "current_thread")] async fn main() {
/// let mut buffer = Vec::new();
/// let mut tokio_buffer = tokio::io::BufWriter::new(&mut buffer);
/// let mut writer = Writer::new_with_indent(&mut tokio_buffer, b' ', 4);
///
/// writer
/// .create_element("paired")
/// .with_attribute(("attr1", "value1"))
/// .with_attribute(("attr2", "value2"))
/// .write_cdata_content_async(BytesCData::new("text & content"))
/// .await
/// .expect("cannot write content");
///
/// tokio_buffer.flush().await.expect("flush failed");
///
/// assert_eq!(
/// std::str::from_utf8(&buffer).unwrap(),
/// r#"<paired attr1="value1" attr2="value2"><![CDATA[text & content]]></paired>"#
/// );
/// # }
pub async fn write_cdata_content_async(
self,
text: BytesCData<'_>,
) -> Result<&'a mut Writer<W>> {
self.writer
.write_event_async(Event::Start(self.start_tag.borrow()))
.await?;
self.writer.write_event_async(Event::CData(text)).await?;
self.writer
.write_event_async(Event::End(self.start_tag.to_end()))
.await?;
Ok(self.writer)
}
/// Write a processing instruction `<?...?>` inside the current element.
///
/// # Example
///
/// ```
/// # use quick_xml::writer::Writer;
/// # use quick_xml::events::BytesPI;
/// # use tokio::io::AsyncWriteExt;
/// # #[tokio::main(flavor = "current_thread")] async fn main() {
/// let mut buffer = Vec::new();
/// let mut tokio_buffer = tokio::io::BufWriter::new(&mut buffer);
/// let mut writer = Writer::new_with_indent(&mut tokio_buffer, b' ', 4);
///
/// writer
/// .create_element("paired")
/// .with_attribute(("attr1", "value1"))
/// .with_attribute(("attr2", "value2"))
/// .write_pi_content_async(BytesPI::new(r#"xml-stylesheet href="style.css""#))
/// .await
/// .expect("cannot write content");
///
/// tokio_buffer.flush().await.expect("flush failed");
///
/// assert_eq!(
/// std::str::from_utf8(&buffer).unwrap(),
/// r#"<paired attr1="value1" attr2="value2">
/// <?xml-stylesheet href="style.css"?>
/// </paired>"#
/// );
/// # }
pub async fn write_pi_content_async(self, text: BytesPI<'_>) -> Result<&'a mut Writer<W>> {
self.writer
.write_event_async(Event::Start(self.start_tag.borrow()))
.await?;
self.writer.write_event_async(Event::PI(text)).await?;
self.writer
.write_event_async(Event::End(self.start_tag.to_end()))
.await?;
Ok(self.writer)
}
/// Write an empty (self-closing) tag.
///
/// # Example
///
/// ```
/// # use quick_xml::writer::Writer;
/// # use quick_xml::events::BytesText;
/// # use tokio::io::AsyncWriteExt;
/// # #[tokio::main(flavor = "current_thread")] async fn main() {
/// let mut buffer = Vec::new();
/// let mut tokio_buffer = tokio::io::BufWriter::new(&mut buffer);
/// let mut writer = Writer::new_with_indent(&mut tokio_buffer, b' ', 4);
///
/// writer
/// .create_element("empty")
/// .with_attribute(("attr1", "value1"))
/// .with_attribute(("attr2", "value2"))
/// .write_empty_async()
/// .await
/// .expect("cannot write content");
///
/// tokio_buffer.flush().await.expect("flush failed");
///
/// assert_eq!(
/// std::str::from_utf8(&buffer).unwrap(),
/// r#"<empty attr1="value1" attr2="value2"/>"#
/// );
/// # }
pub async fn write_empty_async(self) -> Result<&'a mut Writer<W>> {
self.writer
.write_event_async(Event::Empty(self.start_tag))
.await?;
Ok(self.writer)
}
/// Create a new scope for writing XML inside the current element.
///
/// # Example
///
/// ```
/// # use quick_xml::writer::Writer;
/// # use quick_xml::events::BytesText;
/// # use tokio::io::AsyncWriteExt;
/// use quick_xml::Error;
///
/// # #[tokio::main(flavor = "current_thread")] async fn main() {
/// let mut buffer = Vec::new();
/// let mut tokio_buffer = tokio::io::BufWriter::new(&mut buffer);
/// let mut writer = Writer::new_with_indent(&mut tokio_buffer, b' ', 4);
///
/// writer
/// .create_element("outer")
/// .with_attributes([("attr1", "value1"), ("attr2", "value2")])
/// // We need to provide error type, because it is not named somewhere explicitly
/// .write_inner_content_async::<_, _, Error>(|writer| async move {
/// let fruits = ["apple", "orange", "banana"];
/// for (quant, item) in fruits.iter().enumerate() {
/// writer
/// .create_element("fruit")
/// .with_attributes([("quantity", quant.to_string().as_str())])
/// .write_text_content_async(BytesText::new(item))
/// .await?;
/// }
/// writer
/// .create_element("inner")
/// .write_inner_content_async(|writer| async move {
/// writer.create_element("empty").write_empty_async().await
/// })
/// .await?;
///
/// Ok(writer)
/// })
/// .await
/// .expect("cannot write content");
///
/// tokio_buffer.flush().await.expect("flush failed");
/// assert_eq!(
/// std::str::from_utf8(&buffer).unwrap(),
/// r#"<outer attr1="value1" attr2="value2">
/// <fruit quantity="0">apple</fruit>
/// <fruit quantity="1">orange</fruit>
/// <fruit quantity="2">banana</fruit>
/// <inner>
/// <empty/>
/// </inner>
/// </outer>"#
/// );
/// # }
pub async fn write_inner_content_async<F, Fut, E>(
mut self,
closure: F,
) -> StdResult<&'a mut Writer<W>, E>
where
F: FnOnce(&'a mut Writer<W>) -> Fut,
Fut: Future<Output = StdResult<&'a mut Writer<W>, E>>,
E: From<Error>,
{
self.writer
.write_event_async(Event::Start(self.start_tag.borrow()))
.await?;
self.writer = closure(self.writer).await?;
self.writer
.write_event_async(Event::End(self.start_tag.to_end()))
.await?;
Ok(self.writer)
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::events::*;
use pretty_assertions::assert_eq;
macro_rules! test {
($name: ident, $event: expr, $expected: expr) => {
#[tokio::test]
async fn $name() {
let mut buffer = Vec::new();
let mut writer = Writer::new(&mut buffer);
writer
.write_event_async($event)
.await
.expect("write event failed");
assert_eq!(std::str::from_utf8(&buffer).unwrap(), $expected,);
}
};
}
test!(
xml_header,
Event::Decl(BytesDecl::new("1.0", Some("UTF-8"), Some("no"))),
r#"<?xml version="1.0" encoding="UTF-8" standalone="no"?>"#
);
test!(empty_tag, Event::Empty(BytesStart::new("tag")), r#"<tag/>"#);
test!(
comment,
Event::Comment(BytesText::new("this is a comment")),
r#"<!--this is a comment-->"#
);
test!(
cdata,
Event::CData(BytesCData::new("this is a cdata")),
r#"<![CDATA[this is a cdata]]>"#
);
test!(
pi,
Event::PI(BytesPI::new("this is a processing instruction")),
r#"<?this is a processing instruction?>"#
);
test!(
doctype,
Event::DocType(BytesText::new("this is a doctype")),
r#"<!DOCTYPE this is a doctype>"#
);
#[tokio::test]
async fn full_tag() {
let mut buffer = Vec::new();
let mut writer = Writer::new(&mut buffer);
let start = Event::Start(BytesStart::new("tag"));
let text = Event::Text(BytesText::new("inner text"));
let end = Event::End(BytesEnd::new("tag"));
for i in [start, text, end] {
writer.write_event_async(i).await.expect("write tag failed");
}
assert_eq!(
std::str::from_utf8(&buffer).unwrap(),
r#"<tag>inner text</tag>"#
);
}
}
#[cfg(test)]
mod indentation_async {
use super::*;
use crate::events::*;
use pretty_assertions::assert_eq;
#[tokio::test]
async fn self_closed() {
let mut buffer = Vec::new();
let mut writer = Writer::new_with_indent(&mut buffer, b' ', 4);
let tag = BytesStart::new("self-closed")
.with_attributes(vec![("attr1", "value1"), ("attr2", "value2")].into_iter());
writer
.write_event_async(Event::Empty(tag))
.await
.expect("write tag failed");
assert_eq!(
std::str::from_utf8(&buffer).unwrap(),
r#"<self-closed attr1="value1" attr2="value2"/>"#
);
}
#[tokio::test]
async fn empty_paired() {
let mut buffer = Vec::new();
let mut writer = Writer::new_with_indent(&mut buffer, b' ', 4);
let start = BytesStart::new("paired")
.with_attributes(vec![("attr1", "value1"), ("attr2", "value2")].into_iter());
let end = start.to_end();
writer
.write_event_async(Event::Start(start.clone()))
.await
.expect("write start tag failed");
writer
.write_event_async(Event::End(end))
.await
.expect("write end tag failed");
assert_eq!(
std::str::from_utf8(&buffer).unwrap(),
r#"<paired attr1="value1" attr2="value2">
</paired>"#
);
}
#[tokio::test]
async fn paired_with_inner() {
let mut buffer = Vec::new();
let mut writer = Writer::new_with_indent(&mut buffer, b' ', 4);
let start = BytesStart::new("paired")
.with_attributes(vec![("attr1", "value1"), ("attr2", "value2")].into_iter());
let end = start.to_end();
let inner = BytesStart::new("inner");
writer
.write_event_async(Event::Start(start.clone()))
.await
.expect("write start tag failed");
writer
.write_event_async(Event::Empty(inner))
.await
.expect("write inner tag failed");
writer
.write_event_async(Event::End(end))
.await
.expect("write end tag failed");
assert_eq!(
std::str::from_utf8(&buffer).unwrap(),
r#"<paired attr1="value1" attr2="value2">
<inner/>
</paired>"#
);
}
#[tokio::test]
async fn paired_with_text() {
let mut buffer = Vec::new();
let mut writer = Writer::new_with_indent(&mut buffer, b' ', 4);
let start = BytesStart::new("paired")
.with_attributes(vec![("attr1", "value1"), ("attr2", "value2")].into_iter());
let end = start.to_end();
let text = BytesText::new("text");
writer
.write_event_async(Event::Start(start.clone()))
.await
.expect("write start tag failed");
writer
.write_event_async(Event::Text(text))
.await
.expect("write text failed");
writer
.write_event_async(Event::End(end))
.await
.expect("write end tag failed");
assert_eq!(
std::str::from_utf8(&buffer).unwrap(),
r#"<paired attr1="value1" attr2="value2">text</paired>"#
);
}
#[tokio::test]
async fn mixed_content() {
let mut buffer = Vec::new();
let mut writer = Writer::new_with_indent(&mut buffer, b' ', 4);
let start = BytesStart::new("paired")
.with_attributes(vec![("attr1", "value1"), ("attr2", "value2")].into_iter());
let end = start.to_end();
let text = BytesText::new("text");
let inner = BytesStart::new("inner");
writer
.write_event_async(Event::Start(start.clone()))
.await
.expect("write start tag failed");
writer
.write_event_async(Event::Text(text))
.await
.expect("write text failed");
writer
.write_event_async(Event::Empty(inner))
.await
.expect("write inner tag failed");
writer
.write_event_async(Event::End(end))
.await
.expect("write end tag failed");
assert_eq!(
std::str::from_utf8(&buffer).unwrap(),
r#"<paired attr1="value1" attr2="value2">text<inner/>
</paired>"#
);
}
#[tokio::test]
async fn nested() {
let mut buffer = Vec::new();
let mut writer = Writer::new_with_indent(&mut buffer, b' ', 4);
let start = BytesStart::new("paired")
.with_attributes(vec![("attr1", "value1"), ("attr2", "value2")].into_iter());
let end = start.to_end();
let inner = BytesStart::new("inner");
writer
.write_event_async(Event::Start(start.clone()))
.await
.expect("write start 1 tag failed");
writer
.write_event_async(Event::Start(start.clone()))
.await
.expect("write start 2 tag failed");
writer
.write_event_async(Event::Empty(inner))
.await
.expect("write inner tag failed");
writer
.write_event_async(Event::End(end.clone()))
.await
.expect("write end tag 2 failed");
writer
.write_event_async(Event::End(end))
.await
.expect("write end tag 1 failed");
assert_eq!(
std::str::from_utf8(&buffer).unwrap(),
r#"<paired attr1="value1" attr2="value2">
<paired attr1="value1" attr2="value2">
<inner/>
</paired>
</paired>"#
);
}
}