Render HTML with loaded JavaScript to stdout using Wry

readme.md

Render HTML and print it to stdout after window.onload using wry

Initially posted at tauri-apps/wry#761 (reply in thread).

Steps

Save code from main.rs somewhere

Compile script

cargo build -r

Execute script

It takes about one second to render HTML with JS and return back the HTML string. Only started checking the profiler.

time ./target/release/wry_test_render
0.17user 0.07system 0:00.81elapsed 30%CPU (0avgtext+0avgdata 80388maxresident)k
0inputs+0outputs (172major+7466minor)pagefaults 0swaps

Double-check that source and resulting files are different

du -sh source.html rendered.html 
688K	source.html
752K	rendered.html

Cargo.toml

[package]
name = "wry_render_html_to_stdout"
authors = [ "Illia <ilya@serpapi.com>" ]
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
wry = "0.22.5"

[profile.release]
debug = 1

main.rs

use std::fs::{canonicalize, read_to_string};

use wry::{
    application::{
        event::{Event, WindowEvent},
        event_loop::{ControlFlow, EventLoop},
        window::{Window, WindowBuilder},
    },
    webview::WebViewBuilder,
};

const RETURN_OUTER_HTML: &str = r#"
window.onload = function() {
  let html = document.documentElement.outerHTML;
  window.ipc.postMessage(html);
}
"#;

fn main() -> wry::Result<()> {
    enum UserEvents {
        CloseWindow,
    }

    let event_loop = EventLoop::<UserEvents>::with_user_event();

    let window = WindowBuilder::new()
        .with_title("Render HTML to string")
        .with_visible(false)
        .build(&event_loop)?;

    let html = read_to_string(canonicalize("./MY_HTML_FILE.html")?)?;

    let proxy = event_loop.create_proxy();

    let handler = move |_window: &Window, html: String| {
        println!("{}", &html);

        let _ = proxy.send_event(UserEvents::CloseWindow);
    };

    let _webview = WebViewBuilder::new(window)?
        .with_html(&html)?
        .with_initialization_script(RETURN_OUTER_HTML)
        .with_ipc_handler(handler)
        .build()?;

    event_loop.run(move |event, _, control_flow| {
        *control_flow = ControlFlow::Wait;

        match event {
            Event::WindowEvent {
                event: WindowEvent::CloseRequested,
                ..
            }
            | Event::UserEvent(UserEvents::CloseWindow) => {
                *control_flow = ControlFlow::Exit
            }
            _ => (),
        }
    });
}