Working

Cargo.toml

@@ -6,3 +6,7 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+actix-web = "4.3.1"
+derive_more = "0.99.17"
+mime = "0.3.17"
+reqwest = "0.11.18"

shell.nix

@@ -15,7 +15,7 @@ pkgs.mkShell {
     ruststable
     rust-analyzer
     bacon
-    #pkg-config
-    #openssl
+    pkg-config
+    openssl
   ];
 }

src/error.rs

@@ -0,0 +1,42 @@
+use actix_web::{HttpResponse, ResponseError};
+use derive_more::From;
+use std::fmt::{self, Display};
+
+pub type Result<T> = std::result::Result<T, Error>;
+
+#[derive(From, Debug)]
+pub enum Error {
+    TatoebaApi(reqwest::Error),
+    NotHuman { target: String },
+}
+
+impl Display for Error {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{:?}", self)
+    }
+}
+
+impl ResponseError for Error {
+    fn status_code(&self) -> reqwest::StatusCode {
+        use reqwest::StatusCode;
+        use Error::*;
+        match self {
+            // 503 Service Unavailable
+            TatoebaApi(error) => error.status().unwrap_or(StatusCode::SERVICE_UNAVAILABLE),
+            // 403 Forbidden
+            NotHuman { .. } => StatusCode::FORBIDDEN,
+        }
+    }
+
+    fn error_response(&self) -> HttpResponse<actix_web::body::BoxBody> {
+        HttpResponse::build(self.status_code()).body(match self {
+            Self::NotHuman { target } => format!(
+               "It looks like you're accessing the Tatoeba API proxy from a script!\n\
+                Tatoeba CORS restrictions do not apply outside of browsers, so please access the API directly:\n\
+                {target}\n\
+                If you feel this is mistake, please open an issue:\n\
+                https://codeberg.org/ElnuDev/tatoeba-api-rs"),
+            _ => self.to_string(),
+        })
+    }
+}

src/main.rs

@@ -1,3 +1,29 @@
-fn main() {
-    println!("Hello, world!");
+mod error;
+pub use error::{Error, Result};
+
+pub mod utils;
+use utils::is_human;
+
+use actix_web::{get, http::header, App, HttpRequest, HttpResponse, HttpServer, Responder};
+
+pub const TATOEBA_API: &str = "https://tatoeba.org/en/api_v0/search";
+
+#[get("/")]
+async fn root(request: HttpRequest) -> Result<impl Responder> {
+    let target = format!("{TATOEBA_API}?{}", request.query_string());
+    if !is_human(&request) {
+        return Err(Error::NotHuman { target });
+    }
+    let resp = reqwest::get(target).await?;
+    Ok(HttpResponse::Ok()
+        .append_header(header::ContentType(mime::APPLICATION_JSON))
+        .body(resp.text().await?))
+}
+
+#[actix_web::main]
+async fn main() -> std::io::Result<()> {
+    HttpServer::new(|| App::new().service(root))
+        .bind(("127.0.0.1", 3001))?
+        .run()
+        .await
 }

src/utils.rs

@@ -0,0 +1,21 @@
+use actix_web::{http::header, HttpRequest};
+
+pub fn is_human(request: &HttpRequest) -> bool {
+    // https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/User-Agent
+    const HUMANS: &[&str] = &[
+        "Firefox", "Chrome",  // Chrome and Chromium browsers
+        "Opera",   // Old Presto-based Opera
+        "Mobile",  // Safari
+        "Trident", // Internet Explorer
+    ];
+    request
+        .headers()
+        .get(header::USER_AGENT)
+        .and_then(|header| header.to_str().ok())
+        .map(|ua| {
+            HUMANS
+                .iter()
+                .any(|&human| ua.contains(human))
+        })
+        .unwrap_or(false)
+}