Package org.codelibs.fess.helper

Class SseResponseHelper

java.lang.Object
org.codelibs.fess.helper.SseResponseHelper
public class SseResponseHelper extends Object
Common helper for Server-Sent Events (SSE) response headers.

Both the v1 chat API (ChatApiManager) and the v2 chat-stream handler (ChatStreamHandler) emit text/event-stream responses and need the same minimum set of response headers to interoperate correctly with browsers and reverse proxies. This helper centralises that header configuration so the baseline cannot drift between the two surfaces.

The X-Accel-Buffering: no header is critical when running behind nginx (or any reverse proxy that defaults to response buffering): without it the entire stream is buffered until the connection closes, which defeats the purpose of SSE and breaks the chat UX.

This is a DI-managed singleton helper; obtain it through ComponentUtil.getSseResponseHelper().

  • Constructor Details

    • SseResponseHelper

      public SseResponseHelper()
      Creates the SSE response helper. Registered as the DI component sseResponseHelper and obtained via ComponentUtil.getSseResponseHelper().

  • Method Details

    • applySseHeaders

      public void applySseHeaders(jakarta.servlet.http.HttpServletResponse response)
      Applies the standard SSE response headers to the given response.

      The following headers are set:

      • Content-Type: text/event-stream; charset=UTF-8 (also sets character encoding)
      • Cache-Control: no-cache — prevent intermediaries from caching the event stream
      • Connection: keep-alive — keep the underlying TCP connection open for streaming
      • X-Accel-Buffering: no — disable response buffering in nginx and similar reverse proxies

      Must be called before any bytes are written to the response so the headers are flushed with the response prelude.

      Parameters:
      response - the HTTP response to configure; must not be null