playwright-rs-trace

Programmatic parser for Playwright trace zip files (trace format v8).

The Playwright JS ecosystem ships a trace-viewer UI but no documented parsing API. This crate fills that gap for Rust:

use playwright_rs_trace::{TraceError, open};

fn main() -> Result<(), TraceError> {
    let mut reader = open("trace.zip")?;
    println!("trace v{} from {}", reader.context().version, reader.context().browser_name);

    for action in reader.actions()? {
        let action = action?;
        if action.error.is_some() {
            eprintln!("failed: {}.{} ({:?})", action.class, action.method, action.error);
        }
    }
    Ok(())
}

The reader is a streaming iterator — events / actions are yielded lazily as the underlying zip stream is read, so a large trace doesn't need to fit in memory before processing begins. This is the property the future browser-hosted WASM trace viewer (issue #82) needs to render partial traces.

Forward compatibility

The parser is conservative about what it knows. Every event is preserved losslessly via TraceReader::raw_events(); only the events() and actions() paths attempt typed deserialization. Event kinds we don't model (or known kinds whose payload schema changes in a future Playwright minor version) surface as TraceEvent::Unknown(RawEvent) — never silently dropped.

If you need to handle a kind we haven't modelled yet, dispatch on RawEvent::kind() and read as_value() for the full JSON.

Status

Pre-1.0. Today: open a trace zip, stream events, reassemble actions, parse network entries. See the crate CHANGELOG for what's shipped; the project's docs/implementation-plans/trace.md tracks the longer roadmap (snapshots, resource loader, action tree, query helpers, WASM compatibility, console + screencast).

Test fixtures

The integration tests parse a checked-in tests/fixtures/basic.trace.zip. Regenerate when the trace format or fixture content changes:

cargo xtask regenerate-trace-fixture

See tests/fixtures/README.md for details.

License

Apache-2.0. See LICENSE (workspace root).