backend/routes/chat.js

import { Router } from "express";
import { z } from "zod";
import { answerWithContext } from "../chat/chatChain.js";
import fs from "node:fs";

export const chatRouter = Router();

const chatBodySchema = z.object({
  message: z.string().min(1),
  sessionId: z.string().min(1).optional(),
  model: z.string().min(1).optional(),
  options: z
    .object({
      temperature: z.number().min(0).max(2).optional(),
      top_p: z.number().min(0).max(1).optional()
    })
    .optional()
});

chatRouter.post("/", async (req, res, next) => {
  try {
    // #region debug-point A:chat-start
    (() => {
      let u = "http://127.0.0.1:7777/event";
      let s = "chat-502-gateway";
      try {
        const e = fs.readFileSync(".dbg/chat-502-gateway.env", "utf8");
        u = e.match(/DEBUG_SERVER_URL=(.+)/)?.[1] || u;
        s = e.match(/DEBUG_SESSION_ID=(.+)/)?.[1] || s;
      } catch {}
      fetch(u, {
        method: "POST",
        headers: { "content-type": "application/json" },
        body: JSON.stringify({
          sessionId: s,
          runId: "post-fix",
          hypothesisId: "A",
          location: "api/routes/chat.js",
          msg: "[DEBUG] /api/chat received",
          data: {
            method: req.method,
            path: req.originalUrl,
            contentType: req.header("content-type") ?? "",
            bodyType: typeof req.body,
            hasBody: Boolean(req.body),
            messageLen: typeof req.body?.message === "string" ? req.body.message.length : null
          },
          ts: Date.now()
        })
      }).catch(() => {});
    })();
    // #endregion
    const body = chatBodySchema.parse(req.body);
    const result = await answerWithContext({
      message: body.message,
      sessionId: body.sessionId,
      model: body.model,
      options: body.options
    });
    res.json(result);
  } catch (err) {
    // #region debug-point D:chat-error
    (() => {
      let u = "http://127.0.0.1:7777/event";
      let s = "chat-502-gateway";
      try {
        const e = fs.readFileSync(".dbg/chat-502-gateway.env", "utf8");
        u = e.match(/DEBUG_SERVER_URL=(.+)/)?.[1] || u;
        s = e.match(/DEBUG_SESSION_ID=(.+)/)?.[1] || s;
      } catch {}
      fetch(u, {
        method: "POST",
        headers: { "content-type": "application/json" },
        body: JSON.stringify({
          sessionId: s,
          runId: "post-fix",
          hypothesisId: "D",
          location: "api/routes/chat.js",
          msg: "[DEBUG] /api/chat error",
          data: {
            name: err?.name ?? null,
            message: typeof err?.message === "string" ? err.message : null,
            statusCode: err?.statusCode ?? err?.status ?? null
          },
          ts: Date.now()
        })
      }).catch(() => {});
    })();
    // #endregion
    next(err);
  }
});