Fix bug where autorewrite was always on, respond 50 and log instead of panic on rewrite error

src/lib.rs

@@ -390,6 +390,7 @@ impl ServerInner {
             request.set_cert(client_cert);
         }
 
+        #[cfg_attr(feature = "gemini_srv", allow(unused_mut))] // Used for scgi_srv only
         let mut response = if let Some((trailing, handler)) = self.routes.match_request(&request) {
             request.set_trailing(trailing);
             handler.handle(request.clone()).await
@@ -397,14 +398,27 @@ impl ServerInner {
             Response::not_found()
         };
 
+        #[cfg(feature = "scgi_srv")] // No point running noop code
+        if self.autorewrite {
             match response.rewrite_all(&request).await {
                 Ok(true) => { /* all is well */ }
-            Ok(false) => panic!("Upstream did not include SCRIPT_PATH or SCRIPT_NAME"),
+                Ok(false) => {
+                    error!(
+                        concat!(
+                        "Upstream did not include SCRIPT_PATH or SCRIPT_NAME, refusing to",
+                        " serve any text/gemini content with absolute links.  It's most",
+                        " likely that the proxy server you're using doesn't correctly",
+                        " or completely implement the SCGI specification.",
+                        )
+                    );
+                    response = Response::temporary_failure("Server misconfigured");
+                },
                 Err(e) => {
                     error!("Error reading text/gemini file from Response reader: {}", e);
                     response = Response::not_found();
                 }
             }
+        }
 
         self.send_response(response, &mut stream).await
             .context("Failed to send response")?;