Function pipeOpenRouterStream

demo/server/openrouter-chat.ts:163–245

(
  res: ServerResponse,
  apiKey: string,
  model: string,
  messages: { role: string; content: string }[],
)

}

async function pipeOpenRouterStream(
  res: ServerResponse,
  apiKey: string,
  model: string,
  messages: { role: string; content: string }[],
): Promise<void> {
  const upstream = await fetch("https://openrouter.ai/api/v1/chat/completions", {
    method: "POST",
    headers: {
      Authorization: `Bearer ${apiKey}`,
      "Content-Type": "application/json",
      "HTTP-Referer": "http://localhost:5173",
      "X-Title": "StreamHtml Chat",
    },
    body: JSON.stringify({
      model,
      messages: [{ role: "system", content: SYSTEM_PROMPT }, ...messages],
      stream: true,
      reasoning: { enabled: true },
    }),
  });

  if (!upstream.ok) {
    const errText = await upstream.text();
    res.statusCode = upstream.status;
    res.setHeader("Content-Type", "application/json");
    res.end(JSON.stringify({ error: errText || upstream.statusText }));
    return;
  }

  if (!upstream.body) {
    res.statusCode = 502;
    res.end("No response body from OpenRouter");
    return;
  }

  res.statusCode = 200;
  res.setHeader("Content-Type", "application/x-ndjson; charset=utf-8");
  res.setHeader("Cache-Control", "no-cache, no-transform");
  res.setHeader("Connection", "keep-alive");
  res.setHeader("X-Content-Type-Options", "nosniff");
  res.flushHeaders?.();

  const reader = upstream.body.getReader();
  const decoder = new TextDecoder();
  let buffer = "";

  try {
    while (true) {
      const { done, value } = await reader.read();
      if (done) {
        break;
      }

      buffer += decoder.decode(value, { stream: true });
      const lines = buffer.split("\n");
      buffer = lines.pop() ?? "";