From d96f415a2cfb55715c095cc9c2775b1413e06203 Mon Sep 17 00:00:00 2001
From: Arnaud Bailly <arnaud.bailly@iohk.io>
Date: Sat, 5 Oct 2024 15:04:10 +0200
Subject: Server can also evaluate expressions

---
 rust/src/web.rs | 51 +++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 49 insertions(+), 2 deletions(-)

(limited to 'rust/src/web.rs')

diff --git a/rust/src/web.rs b/rust/src/web.rs
index 94b01cb..b48900e 100644
--- a/rust/src/web.rs
+++ b/rust/src/web.rs
@@ -2,6 +2,7 @@ use actix_web::{
     get, http::header::ContentType, middleware::Logger, post, web, App, HttpResponse, HttpServer,
     Responder,
 };
+use clap::Parser;
 use futures::try_join;
 use futures::{future::join_all, lock::Mutex};
 use log::info;
@@ -90,8 +91,33 @@ async fn register(
     }
 }
 
+#[post("/eval")]
+async fn eval(input: String) -> impl Responder {
+    let mut env = Environment::new();
+    match parse(&input).first() {
+        Some(expr) => {
+            let output = eval_whnf(expr, &mut env);
+            HttpResponse::Ok().body(format!("{}", output))
+        }
+        None => HttpResponse::BadRequest().finish(),
+    }
+}
+
+#[derive(Parser, Debug)]
+struct Options {
+    /// The port to listen on
+    /// Defaults to 8080
+    #[arg(short, long, default_value_t = 8080)]
+    port: u16,
+    /// The host to bind the server to
+    /// Defaults to 127.0.0.1
+    #[arg(long, default_value = "127.0.0.1")]
+    host: String,
+}
+
 #[tokio::main]
 async fn main() -> std::io::Result<()> {
+    let options = Options::parse();
     let app_state = Arc::new(Mutex::new(State::new()));
     let send_state: Arc<Mutex<State>> = app_state.clone();
     let http_state: Arc<Mutex<dyn AppState>> = app_state;
@@ -103,8 +129,9 @@ async fn main() -> std::io::Result<()> {
             .wrap(Logger::default())
             .app_data(web::Data::new(http_state.clone()))
             .service(register)
+            .service(eval)
     })
-    .bind(("127.0.0.1", 8080))?
+    .bind((options.host, options.port))?
     .run()
     .await
 }
@@ -134,6 +161,7 @@ async fn send_test(grade: u8, url: &String) -> Result<(), String> {
     info!("Sending {} to {}", input, url);
     let response = reqwest::Client::new()
         .post(url)
+        .header("content-type", "text/plain")
         .body(format!("{}", input))
         .send()
         .await;
@@ -141,7 +169,7 @@ async fn send_test(grade: u8, url: &String) -> Result<(), String> {
         Ok(response) => {
             let body = response.text().await.unwrap();
             let vals = parse(&body);
-            // FIXME
+            // FIXME: should be able to handle multiple values
             let result = eval_whnf(vals.first().unwrap(), &mut env);
             info!("Received {} from {}", body, url);
             if result == output {
@@ -256,6 +284,25 @@ mod app_tests {
         );
     }
 
+    #[actix_web::test]
+    async fn post_expression_returns_evaluation() {
+        let app = test::init_service(App::new().wrap(Logger::default()).service(eval)).await;
+
+        let req = test::TestRequest::post()
+            .uri("/eval")
+            .set_payload("((lam (x y) x) 1 2)")
+            .insert_header(ContentType::plaintext())
+            .to_request();
+
+        let resp = test::call_service(&app, req).await;
+
+        assert!(resp.status().is_success());
+
+        let body = resp.into_body();
+        let bytes = body::to_bytes(body).await.unwrap();
+        assert_eq!(bytes, "1".to_string().into_bytes());
+    }
+
     #[test]
     async fn app_does_not_register_same_url_twice() {
         let mut app_state = State::new();
-- 
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