tree_sitter_cli/
playground.rs

1use std::{
2    borrow::Cow,
3    env, fs,
4    net::TcpListener,
5    path::{Path, PathBuf},
6    str::{self, FromStr as _},
7};
8
9use anyhow::{anyhow, Context, Result};
10use tiny_http::{Header, Response, Server};
11
12use super::wasm;
13
14macro_rules! optional_resource {
15    ($name:tt, $path:tt) => {
16        #[cfg(TREE_SITTER_EMBED_WASM_BINDING)]
17        fn $name(tree_sitter_dir: Option<&Path>) -> Cow<'static, [u8]> {
18            if let Some(tree_sitter_dir) = tree_sitter_dir {
19                Cow::Owned(fs::read(tree_sitter_dir.join($path)).unwrap())
20            } else {
21                Cow::Borrowed(include_bytes!(concat!("../../", $path)))
22            }
23        }
24
25        #[cfg(not(TREE_SITTER_EMBED_WASM_BINDING))]
26        fn $name(tree_sitter_dir: Option<&Path>) -> Cow<'static, [u8]> {
27            if let Some(tree_sitter_dir) = tree_sitter_dir {
28                Cow::Owned(fs::read(tree_sitter_dir.join($path)).unwrap())
29            } else {
30                Cow::Borrowed(&[])
31            }
32        }
33    };
34}
35
36optional_resource!(get_playground_js, "docs/src/assets/js/playground.js");
37optional_resource!(get_lib_js, "lib/binding_web/tree-sitter.js");
38optional_resource!(get_lib_wasm, "lib/binding_web/tree-sitter.wasm");
39
40fn get_main_html(tree_sitter_dir: Option<&Path>) -> Cow<'static, [u8]> {
41    tree_sitter_dir.map_or(
42        Cow::Borrowed(include_bytes!("playground.html")),
43        |tree_sitter_dir| {
44            Cow::Owned(fs::read(tree_sitter_dir.join("cli/src/playground.html")).unwrap())
45        },
46    )
47}
48
49pub fn serve(grammar_path: &Path, open_in_browser: bool) -> Result<()> {
50    let server = get_server()?;
51    let (grammar_name, language_wasm) = wasm::load_language_wasm_file(grammar_path)?;
52    let url = format!("http://{}", server.server_addr());
53    println!("Started playground on: {url}");
54    if open_in_browser && webbrowser::open(&url).is_err() {
55        eprintln!("Failed to open '{url}' in a web browser");
56    }
57
58    let tree_sitter_dir = env::var("TREE_SITTER_BASE_DIR").map(PathBuf::from).ok();
59    let main_html = str::from_utf8(&get_main_html(tree_sitter_dir.as_deref()))
60        .unwrap()
61        .replace("THE_LANGUAGE_NAME", &grammar_name)
62        .into_bytes();
63    let playground_js = get_playground_js(tree_sitter_dir.as_deref());
64    let lib_js = get_lib_js(tree_sitter_dir.as_deref());
65    let lib_wasm = get_lib_wasm(tree_sitter_dir.as_deref());
66
67    let html_header = Header::from_str("Content-Type: text/html").unwrap();
68    let js_header = Header::from_str("Content-Type: application/javascript").unwrap();
69    let wasm_header = Header::from_str("Content-Type: application/wasm").unwrap();
70
71    for request in server.incoming_requests() {
72        let res = match request.url() {
73            "/" => response(&main_html, &html_header),
74            "/tree-sitter-parser.wasm" => response(&language_wasm, &wasm_header),
75            "/playground.js" => {
76                if playground_js.is_empty() {
77                    redirect("https://tree-sitter.github.io/tree-sitter/assets/js/playground.js")
78                } else {
79                    response(&playground_js, &js_header)
80                }
81            }
82            "/tree-sitter.js" => {
83                if lib_js.is_empty() {
84                    redirect("https://tree-sitter.github.io/tree-sitter.js")
85                } else {
86                    response(&lib_js, &js_header)
87                }
88            }
89            "/tree-sitter.wasm" => {
90                if lib_wasm.is_empty() {
91                    redirect("https://tree-sitter.github.io/tree-sitter.wasm")
92                } else {
93                    response(&lib_wasm, &wasm_header)
94                }
95            }
96            _ => response(b"Not found", &html_header).with_status_code(404),
97        };
98        request
99            .respond(res)
100            .with_context(|| "Failed to write HTTP response")?;
101    }
102
103    Ok(())
104}
105
106fn redirect(url: &str) -> Response<&[u8]> {
107    Response::empty(302)
108        .with_data("".as_bytes(), Some(0))
109        .with_header(Header::from_bytes("Location", url.as_bytes()).unwrap())
110}
111
112fn response<'a>(data: &'a [u8], header: &Header) -> Response<&'a [u8]> {
113    Response::empty(200)
114        .with_data(data, Some(data.len()))
115        .with_header(header.clone())
116}
117
118fn get_server() -> Result<Server> {
119    let addr = env::var("TREE_SITTER_PLAYGROUND_ADDR").unwrap_or_else(|_| "127.0.0.1".to_owned());
120    let port = env::var("TREE_SITTER_PLAYGROUND_PORT")
121        .map(|v| {
122            v.parse::<u16>()
123                .with_context(|| "Invalid port specification")
124        })
125        .ok();
126    let listener = match port {
127        Some(port) => {
128            bind_to(&addr, port?).with_context(|| "Failed to bind to the specified port")?
129        }
130        None => get_listener_on_available_port(&addr)
131            .with_context(|| "Failed to find a free port to bind to it")?,
132    };
133    let server =
134        Server::from_listener(listener, None).map_err(|_| anyhow!("Failed to start web server"))?;
135    Ok(server)
136}
137
138fn get_listener_on_available_port(addr: &str) -> Option<TcpListener> {
139    (8000..12000).find_map(|port| bind_to(addr, port))
140}
141
142fn bind_to(addr: &str, port: u16) -> Option<TcpListener> {
143    TcpListener::bind(format!("{addr}:{port}")).ok()
144}
tree_sitter_cli/playground.rs

tree_sitter_cli/
playground.rs
