improve user-facing error handling

src/http.rs

@@ -11,8 +11,9 @@ pub enum StatusCode {
     OK,
     BadRequest,
     NotFound,
+    ImATeapot,
     InternalServerError,
-    // ImATeapot,
+    BadGateway,
 }
 
 impl StatusCode {
@@ -21,8 +22,9 @@ impl StatusCode {
             StatusCode::OK => 200,
             StatusCode::BadRequest => 400,
             StatusCode::NotFound => 404,
-            // StatusCode::ImATeapot => 418,
+            StatusCode::ImATeapot => 418,
             StatusCode::InternalServerError => 500,
+            StatusCode::BadGateway => 502,
         }
     }
 

src/main.rs

@@ -53,6 +53,23 @@ fn parse_address(address: &str) -> Result<SocketAddr> {
     }
 }
 
+fn query_error_to_user_response(err: &Error, query_address: &String, address: &SocketAddr) -> (StatusCode, String) {
+    match err.kind() {
+        ErrorKind::HostUnreachable =>
+            (StatusCode::BadGateway, format!(
+                "Host unreachable: {} ({})\n",
+                query_address, address)),
+        ErrorKind::InvalidData =>
+            (StatusCode::BadGateway, format!(
+                "Server returned invalid data: {} ({})\n",
+                query_address, address)),
+        _ =>
+            (StatusCode::InternalServerError, format!(
+                "Failed to connect: {} ({}).\n",
+                query_address, address)),
+    }
+}
+
 fn handle_html_request(request: &Request, response: &mut Response, verbose: bool) -> Result<StatusCode> {
     let content = include_str!("views/index.html");
     response.set_header("Content-Type", "text/html".to_string());
@@ -75,19 +92,16 @@ fn handle_html_request(request: &Request, response: &mut Response, verbose: bool
                 match MinecraftStatus::fetch(&address, verbose) {
                     Err(err) => {
                         println!(
-                            "Failed to connect to {} ({}): {}",
+                            "Failed to query {} ({}): {}",
                             query_address, address, err);
 
-                        response.body(format!(
-                                "Failed to connect to {} ({}).\n",
-                                query_address, address));
-                        response.status(StatusCode::InternalServerError);
+                        let (code, msg) = query_error_to_user_response(&err, query_address, &address);
+
+                        response.status(code);
                         query_response = format!(
                             "<hr/>
                             <h2>Server Details</h2>
-                            <pre><code>Failed to connect to {} ({}).</pre></code>",
-                            sanitize_html(query_address),
-                            sanitize_html(&address.to_string()),
+                            <pre><code>{msg}</pre></code>",
                         );
                     }
                     Ok(status) => {
@@ -155,10 +169,10 @@ fn handle_json_request(request: &Request, response: &mut Response, verbose: bool
                             "Failed to connect to {} ({}): {}",
                             query_address, address, err);
 
-                        response.status(StatusCode::InternalServerError);
-                        response.body(format!(
-                                "Failed to connect to {} ({}).\n",
-                                query_address, address));
+                        let (code, msg) = query_error_to_user_response(&err, query_address, &address);
+
+                        response.status(code);
+                        response.body(msg);
                     }
                     Ok(status) => {
                         let minecraft_status = MinecraftStatusResponse{
@@ -241,7 +255,7 @@ fn main() -> Result<()> {
             Err (e) => {
                 return Err(Error::new(
                         ErrorKind::Other,
-                        format!("Failed to fetch status: {}", e)));
+                        format!("Failed to query server: {}", e)));
             }
         };
     }

src/status.rs

@@ -128,10 +128,16 @@ impl MinecraftStatus {
             }
         }
 
-        let data = std::str::from_utf8(&data[offset..]).expect("Failed to parse UTF-8 data");
+        let data = match std::str::from_utf8(&data[offset..]) {
+            Ok(data) => data,
+            Err(err) => return Err(Error::new(ErrorKind::InvalidData, format!("Failed to parse UTF-8 data: {err}")))
+        };
         let sanitised: String = data.chars().filter(
             |&c| c >= '\u{20}' || c == '\n' || c == '\r' || c == '\t').collect();
-        let status: MinecraftStatus = serde_json::from_str(&sanitised).expect("Failed to parse JSON");
+        let status: MinecraftStatus = match serde_json::from_str(&sanitised) {
+            Ok(status) => status,
+            Err(err) => return Err(Error::new(ErrorKind::InvalidData, format!("Failed to parse JSON: {err}"))),
+        };
 
         Ok(status)
     }