A declarative HTML parser library in Rust, which works like a deserializer from HTML to struct.
use h2s::FromHtml;
use h2s::extraction_method::ExtractNthText;
#[derive(FromHtml, Debug, Eq, PartialEq)]
pub struct Page {
#[h2s(attr = "lang")]
lang: String,
#[h2s(select = "div > h1.blog-title")]
blog_title: String,
#[h2s(select = ".articles > div")]
articles: Vec<Article>,
#[h2s(select = "body", extractor = ExtractNthText(1))]
footer2: String,
}
#[derive(FromHtml, Debug, Eq, PartialEq)]
pub struct Article {
#[h2s(select = "h2 > a")]
title: String,
#[h2s(select = "div > span")]
view_count: usize,
#[h2s(select = "h2 > a", attr = "href")]
url: String,
#[h2s(select = "ul > li")]
tags: Vec<String>,
#[h2s(select = "ul > li:nth-child(1)")]
first_tag: Option<String>,
}
let html = r#"
<html lang="en">
<body>
<div>
<h1 class="blog-title">My tech blog</h1>
<div class="articles">
<div>
<h2><a href="https://example.com/1">article1</a></h2>
<div><span>901</span> Views</div>
<ul><li>Tag1</li><li>Tag2</li></ul>
</div>
<div>
<h2><a href="https://example.com/2">article2</a></h2>
<div><span>849</span> Views</div>
<ul></ul>
</div>
<div>
<h2><a href="https://example.com/3">article3</a></h2>
<div><span>103</span> Views</div>
<ul><li>Tag3</li></ul>
</div>
</div>
</div>
footer1
<hr />
footer2
</body>
</html>
"#;
let page = h2s::parse::<Page>(html).unwrap();
assert_eq!(page, Page {
lang: "en".to_string(),
blog_title: "My tech blog".to_string(),
articles: vec![
Article {
title: "article1".to_string(),
url: "https://example.com/1".to_string(),
view_count: 901,
tags: vec!["Tag1".to_string(), "Tag2".to_string()],
first_tag: Some("Tag1".to_string()),
},
Article {
title: "article2".to_string(),
url: "https://example.com/2".to_string(),
view_count: 849,
tags: vec![],
first_tag: None,
},
Article {
title: "article3".to_string(),
url: "https://example.com/3".to_string(),
view_count: 103,
tags: vec!["Tag3".to_string()],
first_tag: Some("Tag3".to_string()),
},
],
footer2: "footer2".to_string(),
});
// When the input HTML document structure does not match the expected,
// `h2s::parse` will return an error with a detailed reason.
let invalid_html = html.replace(r#"<a href="https://example.com/3">article3</a>"#, "");
let err = h2s::parse::<Page>(invalid_html).unwrap_err();
assert_eq!(
err.to_string(),
"articles: [2]: title: mismatched number of selected elements by \"h2 > a\": expected exactly one element, but no elements found"
);You can use the following types as a field value of the struct to parse.
String- Numeric types (
usize,i64,NonZeroU32, ... ) - And more built-in supported types (List)
- Or you can use any types by implementing yourself (Example)
[T;N]Option<T>Vec<T>
MIT
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