//! Atward implements TVL's redirection service, living at
//! atward.tvl.fyi
//!
//! This service is designed to be added as a search engine to web
//! browsers and attempts to send users to useful locations based on
//! their search query (falling back to another search engine).
use regex::Regex;
use rouille::input::cookies;
use rouille::{Request, Response};
/// A query handler supported by atward. It consists of a pattern on
/// which to match and trigger the query, and a function to execute
/// that returns the target URL.
struct Handler {
/// Regular expression on which to match the query string.
pattern: Regex,
/// Function to construct the target URL. If the pattern matches,
/// this is invoked with the captured matches and the entire URI.
///
/// Returning `None` causes atward to fall through to the next
/// query (and eventually to the default search engine).
target: for<'s> fn(&Query, regex::Captures<'s>) -> Option<String>,
}
/// An Atward query supplied by a user.
#[derive(Debug, PartialEq)]
struct Query {
/// Query string itself.
query: String,
/// Should Sourcegraph be used instead of cgit?
cs: bool,
}
/// Helper function for setting a parameter based on a query
/// parameter.
fn query_setting(req: &Request, config: &mut bool, param: &str) {
match req.get_param(param) {
Some(s) if s == "true" => *config = true,
Some(s) if s == "false" => *config = false,
_ => {}
}
}
impl Query {
fn from_request(req: &Request) -> Option<Query> {
// First extract the actual search query ...
let mut query = match req.get_param("q") {
Some(query) => Query { query, cs: false },
None => return None,
};
// ... then apply settings to it. Settings in query parameters
// take precedence over cookies.
for cookie in cookies(req) {
match cookie {
("cs", "true") => {
query.cs = true;
}
_ => {}
}
}
query_setting(req, &mut query.cs, "cs");
Some(query)
}
}
#[cfg(test)]
impl From<&str> for Query {
fn from(query: &str) -> Query {
Query {
query: query.to_string(),
cs: false,
}
}
}
/// Create a URL to a file (and, optionally, specific line) in cgit.
fn cgit_url(path: &str) -> String {
if path.ends_with(".md") {
format!("https://code.tvl.fyi/about/{}", path)
} else {
format!("https://code.tvl.fyi/tree/{}", path)
}
}
/// Create a URL to a path in Sourcegraph.
fn sourcegraph_path_url(path: &str) -> String {
format!("https://cs.tvl.fyi/depot/-/tree/{}", path)
}
/// Definition of all supported query handlers in atward.
fn handlers() -> Vec<Handler> {
vec![
// Bug IDs (e.g. b/123)
Handler {
pattern: Regex::new("^b/(?P<bug>\\d+)$").unwrap(),
target: |_, captures| Some(format!("https://b.tvl.fyi/{}", &captures["bug"])),
},
// Changelists (e.g. cl/42)
Handler {
pattern: Regex::new("^cl/(?P<cl>\\d+)$").unwrap(),
target: |_, captures| Some(format!("https://cl.tvl.fyi/{}", &captures["cl"])),
},
// Non-parameterised short hostnames should redirect to $host.tvl.fyi
Handler {
pattern: Regex::new("^(?P<host>b|cl|cs|code|at|todo)$").unwrap(),
target: |_, captures| Some(format!("https://{}.tvl.fyi/", &captures["host"])),
},
// Depot paths (e.g. //web/atward or //ops/nixos/whitby/default.nix)
// TODO(tazjin): Add support for specifying lines in a query parameter
Handler {
pattern: Regex::new("^//(?P<path>[a-zA-Z].*)?$").unwrap(),
target: |query, captures| {
// Pass an empty string if the path is missing, to
// redirect to the depot root.
let path = captures.name("path")
.map(|m| m.as_str())
.unwrap_or("");
if query.cs {
Some(sourcegraph_path_url(path))
} else {
Some(cgit_url(path))
}
},
},
]
}
/// Attempt to match against all known query types, and return the
/// destination URL if one is found.
fn dispatch(handlers: &[Handler], query: &Query) -> Option<String> {
for handler in handlers {
if let Some(captures) = handler.pattern.captures(&query.query) {
if let Some(destination) = (handler.target)(query, captures) {
return Some(destination);
}
}
}
None
}
/// Return the opensearch.xml file which is required for adding atward
/// as a search engine in Firefox.
fn opensearch() -> Response {
Response::text(include_str!("opensearch.xml"))
.with_unique_header("Content-Type", "application/opensearchdescription+xml")
}
/// Render the atward index page which gives users some information
/// about how to use the service.
fn index() -> Response {
Response::html(include_str!(env!("ATWARD_INDEX_HTML")))
}
/// Render the fallback page which informs users that their query is
/// unsupported.
fn fallback() -> Response {
Response::text("error for emphasis that i am angery and the query whimchst i angery atward")
.with_status_code(404)
}
fn main() {
let queries = handlers();
let address = std::env::var("ATWARD_LISTEN_ADDRESS")
.expect("ATWARD_LISTEN_ADDRESS environment variable must be set");
rouille::start_server(&address, move |request| {
rouille::log(&request, std::io::stderr(), || {
if request.url() == "/opensearch.xml" {
return opensearch();
}
let query = match Query::from_request(&request) {
Some(q) => q,
None => return index(),
};
match dispatch(&queries, &query) {
None => fallback(),
Some(destination) => Response::redirect_303(destination),
}
})
});
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn bug_query() {
assert_eq!(
dispatch(&handlers(), &"b/42".into()),
Some("https://b.tvl.fyi/42".to_string())
);
assert_eq!(
dispatch(&handlers(), &"something only mentioning b/42".into()),
None,
);
assert_eq!(dispatch(&handlers(), &"b/invalid".into()), None,);
}
#[test]
fn cl_query() {
assert_eq!(
dispatch(&handlers(), &"cl/42".into()),
Some("https://cl.tvl.fyi/42".to_string())
);
assert_eq!(
dispatch(&handlers(), &"something only mentioning cl/42".into()),
None,
);
assert_eq!(dispatch(&handlers(), &"cl/invalid".into()), None,);
}
#[test]
fn depot_path_cgit_query() {
assert_eq!(
dispatch(&handlers(), &"//web/atward/default.nix".into()),
Some("https://code.tvl.fyi/tree/web/atward/default.nix".to_string()),
);
assert_eq!(
dispatch(&handlers(), &"//nix/readTree/README.md".into()),
Some("https://code.tvl.fyi/about/nix/readTree/README.md".to_string()),
);
assert_eq!(dispatch(&handlers(), &"/not/a/depot/path".into()), None);
}
#[test]
fn depot_path_sourcegraph_query() {
assert_eq!(
dispatch(
&handlers(),
&Query {
query: "//web/atward/default.nix".to_string(),
cs: true,
}
),
Some("https://cs.tvl.fyi/depot/-/tree/web/atward/default.nix".to_string()),
);
assert_eq!(
dispatch(
&handlers(),
&Query {
query: "/not/a/depot/path".to_string(),
cs: true,
}
),
None
);
}
#[test]
fn depot_root_cgit_query() {
assert_eq!(
dispatch(
&handlers(),
&Query {
query: "//".to_string(),
cs: false,
}
),
Some("https://code.tvl.fyi/tree/".to_string()),
);
}
#[test]
fn plain_host_queries() {
assert_eq!(
dispatch(&handlers(), &"cs".into()),
Some("https://cs.tvl.fyi/".to_string()),
);
assert_eq!(
dispatch(&handlers(), &"cl".into()),
Some("https://cl.tvl.fyi/".to_string()),
);
assert_eq!(
dispatch(&handlers(), &"b".into()),
Some("https://b.tvl.fyi/".to_string()),
);
assert_eq!(
dispatch(&handlers(), &"todo".into()),
Some("https://todo.tvl.fyi/".to_string()),
);
}
#[test]
fn request_to_query() {
assert_eq!(
Query::from_request(&Request::fake_http("GET", "/?q=b%2F42", vec![], vec![]))
.expect("request should parse to a query"),
Query {
query: "b/42".to_string(),
cs: false,
},
);
assert_eq!(
Query::from_request(&Request::fake_http("GET", "/", vec![], vec![])),
None
);
}
#[test]
fn settings_from_cookie() {
assert_eq!(
Query::from_request(&Request::fake_http(
"GET",
"/?q=b%2F42",
vec![("Cookie".to_string(), "cs=true;".to_string())],
vec![]
))
.expect("request should parse to a query"),
Query {
query: "b/42".to_string(),
cs: true,
},
);
}
#[test]
fn settings_from_query_parameter() {
assert_eq!(
Query::from_request(&Request::fake_http(
"GET",
"/?q=b%2F42&cs=true",
vec![],
vec![]
))
.expect("request should parse to a query"),
Query {
query: "b/42".to_string(),
cs: true,
},
);
// Query parameter should override cookie
assert_eq!(
Query::from_request(&Request::fake_http(
"GET",
"/?q=b%2F42&cs=false",
vec![("Cookie".to_string(), "cs=true;".to_string())],
vec![]
))
.expect("request should parse to a query"),
Query {
query: "b/42".to_string(),
cs: false,
},
);
}
}
