feat(web/atward): Implement match scaffolding for TVL redirector

atward is going to be a new TVL service, living at atward.tvl.fyi,
which users can configure as a search engine in their browser.

It will understand a variety of TVL-specific query types (such as
bug/CL links or code paths). In the future it might also support
features like go-links.

This commit configures the initial setup for query matchers in atward
and adds an example query type (for bugs).

This is not yet wired up to a web server.

Change-Id: Ifaf06c3f5cc378eee7894b7576ef583fc89264f0
Reviewed-on: https://cl.tvl.fyi/c/depot/+/3087
Tested-by: BuildkiteCI
Reviewed-by: isomer <isomer@tvl.fyi>
This commit is contained in:
Vincent Ambo 2021-05-03 23:31:05 +02:00 committed by tazjin
parent 35aa79d14b
commit 51b5475f40
5 changed files with 1085 additions and 0 deletions

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result
/target
**/*.rs.bk

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[package]
name = "atward"
version = "0.1.0"
authors = ["Vincent Ambo <mail@tazj.in>"]
edition = "2018"
[dependencies]
regex = "1.5"
rouille = "3.0"

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{ depot, ... }:
depot.third_party.naersk.buildPackage {
src = ./.;
}

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//! 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;
/// A query type 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 Query {
/// 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(&'s str, regex::Captures<'s>) -> Option<String>,
}
/// Definition of all supported queries in atward.
fn queries() -> Vec<Query> {
vec![
// Bug IDs (e.g. b/123)
Query {
pattern: Regex::new("^b/(?P<bug>\\d+)$").unwrap(),
target: |_, captures| Some(format!("https://b.tvl.fyi/{}", &captures["bug"])),
},
]
}
/// Attempt to match against all known query types, and return the
/// destination URL if one is found.
fn dispatch(queries: &[Query], uri: &str) -> Option<String> {
for query in queries {
if let Some(captures) = query.pattern.captures(uri) {
if let Some(destination) = (query.target)(uri, captures) {
return Some(destination);
}
}
}
None
}
fn main() {
println!("Hello, world!");
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn bug_query() {
assert_eq!(
dispatch(&queries(), "b/42"),
Some("https://b.tvl.fyi/42".to_string())
);
assert_eq!(dispatch(&queries(), "something only mentioning b/42"), None,);
assert_eq!(dispatch(&queries(), "b/invalid"), None,);
}
}