Cancel request on invalid Unicode character

It's pointless to continue as file names mostly don't contain invalid
Unicode.

Signed-off-by: Alexey Yerin <yerinalexey98fd@gmail.com>

src/error.rs

@@ -17,6 +17,9 @@ pub enum TaurusError {
     #[error("invalid request: {0}")]
     InvalidRequest(String),
 
+    #[error("invalid Unicode character in the input")]
+    InvalidUnicode(#[from] std::string::FromUtf8Error),
+
     #[error("failed to bind: {0}")]
     BindFailed(io::Error),
 

src/main.rs

@@ -99,7 +99,7 @@ fn handle_client(mut stream: TlsStream<TcpStream>, static_root: &str) -> TaurusR
         .read(&mut buffer)
         .map_err(TaurusError::StreamReadFailed)?;
 
-    let raw_request = String::from_utf8_lossy(&buffer[..]).into_owned();
+    let raw_request = String::from_utf8(buffer.to_vec())?;
 
     let request = GeminiRequest::parse(&raw_request)?;
     let url_path = request.file_path();