fix(proxy): parse SSE fields with optional spaces in streaming handlers (#1664)

* fix(proxy): handle SSE fields with or without spaces

* refactor(proxy): deduplicate SSE field parsing

src-tauri/src/proxy/response_handler.rs

@@ -5,6 +5,7 @@
 use super::session::ProxySession;
 use super::usage::parser::TokenUsage;
 use super::ProxyError;
+use crate::proxy::sse::strip_sse_field;
 use bytes::Bytes;
 use futures::stream::{Stream, StreamExt};
 use serde_json::Value;
@@ -90,7 +91,7 @@ impl StreamHandler {
                             buffer = buffer[pos + 2..].to_string();
 
                             for line in event_text.lines() {
-                                if let Some(data) = line.strip_prefix("data: ") {
+                                if let Some(data) = strip_sse_field(line, "data") {
                                     if data.trim() != "[DONE]" {
                                         if let Ok(json) = serde_json::from_str::<Value>(data) {
                                             let mut guard = events.lock().await;
@@ -211,4 +212,24 @@ mod tests {
         let handler = StreamHandler::new(30);
         assert_eq!(handler.idle_timeout, Duration::from_secs(30));
     }
+
+    #[test]
+    fn test_strip_sse_field_accepts_optional_space() {
+        assert_eq!(
+            super::strip_sse_field("data: {\"ok\":true}", "data"),
+            Some("{\"ok\":true}")
+        );
+        assert_eq!(
+            super::strip_sse_field("data:{\"ok\":true}", "data"),
+            Some("{\"ok\":true}")
+        );
+        assert_eq!(
+            super::strip_sse_field("event: message_start", "event"),
+            Some("message_start")
+        );
+        assert_eq!(
+            super::strip_sse_field("event:message_start", "event"),
+            Some("message_start")
+        );
+    }
 }