17 unstable releases (6 breaking)
0.7.0 | Oct 30, 2024 |
---|---|
0.5.7 | Jul 26, 2023 |
0.5.2 | Jun 20, 2022 |
0.4.0 | Jan 29, 2022 |
0.2.1 | Nov 27, 2021 |
#94 in Web programming
11,496 downloads per month
Used in 6 crates
(5 directly)
315KB
7.5K
SLoC
html5gum
html5gum
is a WHATWG-compliant HTML tokenizer.
use std::fmt::Write;
use html5gum::{Tokenizer, Token};
let html = "<title >hello world</title>";
let mut new_html = String::new();
for Ok(token) in Tokenizer::new(html) {
match token {
Token::StartTag(tag) => {
write!(new_html, "<{}>", String::from_utf8_lossy(&tag.name)).unwrap();
}
Token::String(hello_world) => {
write!(new_html, "{}", String::from_utf8_lossy(&hello_world)).unwrap();
}
Token::EndTag(tag) => {
write!(new_html, "</{}>", String::from_utf8_lossy(&tag.name)).unwrap();
}
_ => panic!("unexpected input"),
}
}
assert_eq!(new_html, "<title>hello world</title>");
html5gum
provides multiple kinds of APIs:
- Iterating over tokens as shown above.
- Implementing your own
Emitter
for maximum performance, see thecustom_emitter.rs
example. - A callbacks-based API for a middleground between convenience and performance, see the
callback_emitter.rs
example. - With the
tree-builder
feature, html5gum can be integrated withhtml5ever
andscraper
. See thescraper.rs
example.
What a tokenizer does and what it does not do
html5gum
fully implements 13.2.5 of the WHATWG HTML
spec, i.e. is able to tokenize HTML documents and passes html5lib's tokenizer
test suite. Since it is just a tokenizer, this means:
html5gum
does not implement charset detection. This implementation takes and returns bytes, but assumes UTF-8. It recovers gracefully from invalid UTF-8.html5gum
does not correct mis-nested tags.html5gum
doesn't implement the DOM, and unfortunately in the HTML spec, constructing the DOM ("tree construction") influences how tokenization is done. For an example of which problems this causes see this example code.html5gum
does not generally qualify as a browser-grade HTML parser as per the WHATWG spec. This can change in the future, see issue 21.
With those caveats in mind, html5gum
can pretty much parse tokenize
anything that browsers can. However, using the experimental tree-builder
feature, html5gum can be integrated with html5ever
and scraper
. See the
scraper.rs
example.
Other features
- No unsafe Rust
- Only dependency is
jetscii
, and can be disabled via crate features (seeCargo.toml
)
Alternative HTML parsers
html5gum
was created out of a need to parse HTML tag soup efficiently. Previous options were to:
-
use quick-xml or xmlparser with some hacks to make either one not choke on bad HTML. For some (rather large) set of HTML input this works well (particularly
quick-xml
can be configured to be very lenient about parsing errors) and parsing speed is stellar. But neither can parse all HTML.For my own usecase
html5gum
is about 2x slower thanquick-xml
. -
use html5ever's own tokenizer to avoid as much tree-building overhead as possible. This was functional but had poor performance for my own usecase (10-15x slower than
quick-xml
). -
use lol-html, which would probably perform at least as well as
html5gum
, but comes with a closure-based API that I didn't manage to get working for my usecase.
Etymology
Why is this library called html5gum
?
-
G.U.M: Giant Unreadable Match-statement
-
<insert "how it feels to
chew 5 gumparse HTML" meme here>
License
Licensed under the MIT license, see ./LICENSE
.
Dependencies
~0–4.5MB