How do I parse HTML with html5ever in Rust?

Add the crate via Cargo and refer to examples like html2html.rs, which demonstrate basic parsing and serialization using callbacks for DOM handling.

html5ever vs html5lib: which is better for web scraping?

html5ever offers Rust-based performance and safety, ideal for high-throughput scraping, while html5lib is Python-focused and easier for quick scripts; choose based on language and speed requirements.

Does html5ever support XHTML parsing?

For correct XHTML parsing, use an XML parser, as html5ever is optimized for HTML, though it can handle HTML-compatible XHTML documents commonly found.

What are the performance benchmarks for html5ever?

It aims for C-like speed with Rust safety, but specific benchmarks vary by use case; the README emphasizes its design for browser-grade performance without published comparisons.

How to handle DOM manipulation with html5ever?

Implement callback functions to process elements during parsing, as shown in examples like print-rcdom.rs, since no built-in DOM is provided.

Is html5ever suitable for building a web browser?

Yes, it was developed for Servo and includes hooks like document.write, making it a solid choice for browser engines needing standards-compliant parsing.

Open-Awesome

html5ever

NOASSERTIONRusthtml5ever-v0.35.0

A high-performance, browser-grade HTML5 parser written in Rust, developed as part of the Servo project.

GitHub

2.6k stars275 forks0 contributors

What is html5ever?

html5ever is a high-performance HTML5 parser written in Rust, originally developed for the Servo browser project. It parses and serializes HTML according to WHATWG specifications while providing the hooks needed for browser-grade functionality like document.write. The parser aims to combine C-level performance with Rust's memory safety to avoid common security vulnerabilities.

Target Audience

Developers building web browsers, crawlers, or tools requiring robust HTML parsing, particularly those working in Rust ecosystems or needing standards-compliant, high-performance parsing.

Value Proposition

It offers a unique combination of standards compliance, browser-grade features, and the safety/performance benefits of Rust, making it ideal for projects where security and speed are critical without sacrificing web compatibility.

Overview

High-performance browser-grade HTML5 parser

Use Cases

Best For

Building web browsers or browser engines like Servo
Developing web crawlers that need robust HTML parsing
Creating tools for HTML validation or transformation
Implementing standards-compliant HTML parsers in Rust
Parsing HTML in security-sensitive applications
Projects requiring high-performance parsing with memory safety

Not Ideal For

Projects needing a built-in DOM tree for out-of-the-box manipulation
Non-Rust applications without ready-to-use language bindings
Simple HTML parsing tasks where a lightweight parser suffices

Pros & Cons

Pros

C-Like Performance

Delivers parsing speeds comparable to C while leveraging Rust's memory safety, as highlighted in the README for high-performance needs.

Standards Compliance

Implements WHATWG HTML5 specifications and passes most html5lib tests, ensuring broad web compatibility for real-world use.

Browser-Grade Hooks

Supports essential browser features like document.write, making it suitable for engines requiring full web compatibility.

Memory Safety

Avoids common C security vulnerabilities through Rust's ownership model, providing a secure foundation for parsing.

Cons

No Built-In DOM

Requires custom implementation via callbacks for DOM manipulation, adding complexity compared to parsers with integrated tree representations.

Encoding Limitations

Currently supports only UTF-8, with other encodings planned but not yet implemented, limiting handling of legacy documents.

Incomplete Spec Compliance

Acknowledges differences from WHATWG specs and not all html5lib tests are passed, as documented in the bug tracker.

Frequently Asked Questions

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