hono/dist/helper/streaming/sse.js

Web framework built on Web Standards

// src/helper/streaming/sse.ts
import { StreamingApi } from "../../utils/stream.js";
var SSEStreamingApi = class extends StreamingApi {
  constructor(writable, readable) {
    super(writable, readable);
  }
  async writeSSE(message) {
    const data = message.data.split("\n").map((line) => {
      return `data: ${line}`;
    }).join("\n");
    const sseData = [
      message.event && `event: ${message.event}`,
      data,
      message.id && `id: ${message.id}`,
      message.retry && `retry: ${message.retry}`
    ].filter(Boolean).join("\n") + "\n\n";
    await this.write(sseData);
  }
};
var run = async (stream, cb, onError) => {
  try {
    await cb(stream);
  } catch (e) {
    if (e instanceof Error && onError) {
      await onError(e, stream);
      await stream.writeSSE({
        event: "error",
        data: e.message
      });
    } else {
      console.error(e);
    }
  } finally {
    stream.close();
  }
};
var contextStash = /* @__PURE__ */ new WeakMap();
var streamSSE = (c, cb, onError) => {
  const { readable, writable } = new TransformStream();
  const stream = new SSEStreamingApi(writable, readable);
  c.req.raw.signal.addEventListener("abort", () => {
    if (!stream.closed) {
      stream.abort();
    }
  });
  contextStash.set(stream.responseReadable, c);
  c.header("Transfer-Encoding", "chunked");
  c.header("Content-Type", "text/event-stream");
  c.header("Cache-Control", "no-cache");
  c.header("Connection", "keep-alive");
  run(stream, cb, onError);
  return c.newResponse(stream.responseReadable);
};
export {
  SSEStreamingApi,
  streamSSE
};