Initial commit

src/utils/sse_parser.py

@@ -0,0 +1,109 @@
+from typing import Dict, List, Optional
+
+
+class SSEEventParser:
+    """轻量SSE解析器，按行接收输入并输出完整事件。"""
+
+    def __init__(self) -> None:
+        self._reset_buffer()
+
+    def _reset_buffer(self) -> None:
+        self._buffer: Dict[str, Optional[str] | List[str]] = {
+            "event": None,
+            "data": [],
+            "id": None,
+            "retry": None,
+        }
+
+    def _finalize_event(self) -> Optional[Dict[str, Optional[str]]]:
+        data_lines = self._buffer.get("data", [])
+        if not data_lines:
+            self._reset_buffer()
+            return None
+
+        data_str = "\n".join(data_lines)
+        event = {
+            "event": self._buffer.get("event"),
+            "data": data_str,
+            "id": self._buffer.get("id"),
+            "retry": self._buffer.get("retry"),
+        }
+
+        self._reset_buffer()
+        return event
+
+    def feed_line(self, line: Optional[str]) -> List[Dict[str, Optional[str]]]:
+        """处理单行SSE文本，返回所有完成的事件。"""
+
+        normalized_line = (line or "").rstrip("\r")
+        events: List[Dict[str, Optional[str]]] = []
+
+        # 空行表示事件结束
+        if normalized_line == "":
+            event = self._finalize_event()
+            if event:
+                events.append(event)
+            return events
+
+        # 注释行直接忽略
+        if normalized_line.startswith(":") and not normalized_line.startswith("::"):
+            return events
+
+        if normalized_line.startswith("event:"):
+            _, rest = normalized_line.split(":", 1)
+            value = rest.lstrip()
+
+            if " data:" in value:
+                event_part, data_part = value.split("data:", 1)
+                event_name = event_part.strip() or None
+                data_value = data_part.lstrip()
+                self._buffer["event"] = event_name
+                if data_value:
+                    self._append_data_line(data_value)
+                event = self._finalize_event()
+                if event:
+                    events.append(event)
+            else:
+                event_name = value.strip() or None
+                self._buffer["event"] = event_name
+            return events
+
+        if normalized_line.startswith("data:"):
+            # 如果已经有缓存的 data，先完成上一个事件
+            # 这样可以处理没有空行分隔的连续 data 行
+            existing_data = self._buffer.get("data", [])
+            if existing_data and len(existing_data) > 0:
+                event = self._finalize_event()
+                if event:
+                    events.append(event)
+
+            _, rest = normalized_line.split(":", 1)
+            self._append_data_line(rest[1:] if rest.startswith(" ") else rest)
+            return events
+
+        if normalized_line.startswith("id:"):
+            _, rest = normalized_line.split(":", 1)
+            self._buffer["id"] = rest.strip() or None
+            return events
+
+        if normalized_line.startswith("retry:"):
+            _, rest = normalized_line.split(":", 1)
+            self._buffer["retry"] = rest.strip() or None
+            return events
+
+        # 未知行：视作数据追加（部分实现会缺少 data: 前缀）
+        self._append_data_line(normalized_line)
+        return events
+
+    def flush(self) -> List[Dict[str, Optional[str]]]:
+        """在流结束时调用，输出尚未完成的事件。"""
+
+        event = self._finalize_event()
+        return [event] if event else []
+
+    def _append_data_line(self, value: str) -> None:
+        data_lines = self._buffer.get("data")
+        if isinstance(data_lines, list):
+            data_lines.append(value)
+        else:
+            self._buffer["data"] = [value]