I was just writing the PR and realised that aliases is a better name than keys

asklyphe-frontend/src/bangs.rs

@@ -0,0 +1,106 @@
+use tracing::{debug, error};
+use once_cell::sync::Lazy;
+use std::collections::BTreeMap;
+use url_encoded_data;
+
+pub static BANG_PREFIX: &str = "!";
+
+#[derive(Debug)]
+struct Bang<'a> {
+    pub url: &'a str,
+    pub aliases: &'a [&'a str]
+}
+
+impl<'a> Bang<'_> {
+    fn new(url: &'a str, aliases: &'a [&'a str]) -> Bang<'a> {
+        Bang {url, aliases}
+    }
+}
+
+static BUILTIN_BANGS: Lazy<BTreeMap<&str, Bang>> = Lazy::new(|| {
+    let mut bangs = BTreeMap::new();
+    bangs.insert("Google", Bang::new("https://google.com/search?q={}", &["g", "google"] as &[&str]));
+
+    bangs.insert("DuckDuckGo", Bang::new("https://duckduckgo.com/?q={}", &["d", "ddg", "duckduckgo"] as &[&str]));
+
+    bangs.insert("Wikipedia", Bang::new("https://wikipedia.org/w/index.php?search={}", &["w", "wiki", "wikipedia"] as &[&str]));
+    bangs
+});
+
+#[derive(Debug, Clone)]
+struct BangLoc<'b> {
+    pub url: &'b str,
+    pub start_idx: usize,
+    pub len: usize
+}
+
+impl<'b> BangLoc<'_> {
+    fn new(url: &'b str, start_idx: usize, len: usize) -> BangLoc<'b> {
+        BangLoc {url, start_idx, len}
+    }
+}
+
+pub fn redirect_bang(query: &String) -> Option<String> {
+    if !query.contains(BANG_PREFIX) {
+        return None;
+    }
+    let bangs = query.match_indices(BANG_PREFIX).filter(|(bang_start_idx, _)| {
+        if *bang_start_idx == 0 || query.chars().nth(*bang_start_idx - 1).unwrap().is_whitespace() {
+            true
+        } else {
+            false
+        }
+    }).map(|(bang_start_idx, _)| {
+        let rest = query.get(bang_start_idx + 1..query.len()).unwrap();
+        BUILTIN_BANGS.iter().map(|(_, bang)| {
+            let alias = bang.aliases.iter()
+                .filter(|alias| rest.starts_with(**alias))
+                .filter(
+                    |alias| rest.chars()
+                    .nth(alias.len())
+                    .unwrap_or(' ')
+                    .is_whitespace())
+                .max_by(|a, b| a.len().cmp(&b.len()))?;
+            Some(BangLoc::new(bang.url, bang_start_idx, alias.len()))
+        }).filter(|bang| bang.is_some()).map(|bang| bang.unwrap()).next()
+    }).filter(|bang| bang.is_some())
+    .map(|bang| bang.unwrap())
+    .collect::<Vec<_>>();
+
+
+    let bang = bangs.first()?;
+    let end_idx = {
+        let mut end_idx = bang.start_idx + 1 + bang.len;
+        if end_idx < query.len() {
+            end_idx += 1;
+        }
+        end_idx
+    };
+
+    let start_idx = if end_idx == query.len() && bang.start_idx > 0 {
+        bang.start_idx - 1
+    } else {
+        bang.start_idx
+    };
+
+
+    let query_split = query.split_once(query.get(start_idx..end_idx).unwrap()).unwrap();
+
+    let query_trimmed = format!("{}{}", query_split.0, query_split.1);
+
+    // A hack to get URL escaping without using a proper URL layout, hopefully has no other issues apart from prepending '=' to the string
+    let query_encoded = url_encoded_data::stringify(&[("", query_trimmed.as_str())]);
+    let query_encoded = query_encoded.get(1..query_encoded.len()).unwrap().to_owned();
+
+
+    let bang_url_split = bang.url.split_once("{}").unwrap();
+
+    let bang_url = format!(
+        "{}{}{}",
+        bang_url_split.0,
+        query_encoded,
+        bang_url_split.1
+    );
+
+    Some(bang_url)
+}

asklyphe-frontend/src/main.rs

@@ -14,6 +14,7 @@
 pub mod searchbot;
 pub mod wikipedia;
 pub mod unit_converter;
+pub mod bangs;
 pub mod routes;
 
 use std::{env, process};

asklyphe-frontend/src/routes/search.rs

@@ -18,6 +18,7 @@ use crate::unit_converter;
 use crate::unit_converter::UnitConversion;
 use crate::wikipedia::WikipediaSummary;
 use crate::{wikipedia, Opts, ALPHA, BUILT_ON, GIT_COMMIT, VERSION, YEAR};
+use crate::bangs;
 use askama::Template;
 use asklyphe_common::nats;
 use asklyphe_common::nats::bingservice::{
@@ -170,6 +171,11 @@ pub async fn search_js(
             unit_query = unit_query.replace("metre", "meter");
             let unit_comp = unit_converter::convert_unit(&unit_query);
             complications.unit_converter = unit_comp;
+
+            let bang_redirect = bangs::redirect_bang(&query);
+            if let Some(redirect) = bang_redirect {
+                return Redirect::to(&redirect).into_response();
+            }
         } else {
             complications.disabled = true;
             query = query.replace("-complications", "");
@@ -282,6 +288,11 @@ pub async fn search_nojs(
             unit_query = unit_query.replace("metre", "meter");
             let unit_comp = unit_converter::convert_unit(&unit_query);
             complications.unit_converter = unit_comp;
+
+            let bang_redirect = bangs::redirect_bang(&query);
+            if let Some(redirect) = bang_redirect {
+                return Redirect::to(&redirect).into_response();
+            }
         } else {
             complications.disabled = true;
             query = query.replace("-complications", "");