fal-js/libs/proxy/src/express.ts

import type { RequestHandler } from "express";
import { DEFAULT_PROXY_ROUTE, handleRequest } from "./index";

/**
 * The default Express route for the fal.ai client proxy.
 */
export const route = DEFAULT_PROXY_ROUTE;

/**
 * The Express route handler for the fal.ai client proxy.
 *
 * @param request The Express request object.
 * @param response The Express response object.
 * @param next The Express next function.
 */
export const handler: RequestHandler = async (request, response, next) => {
  await handleRequest({
    id: "express",
    method: request.method,
    getRequestBody: async () => JSON.stringify(request.body),
    getHeaders: () => request.headers,
    getHeader: (name) => request.headers[name],
    sendHeader: (name, value) => response.setHeader(name, value),
    respondWith: (status, data) => response.status(status).json(data),
    sendResponse: async (res) => {
      if (res.body instanceof ReadableStream) {
        const reader = res.body.getReader();
        const stream = async () => {
          const { done, value } = await reader.read();
          if (done) {
            response.end();
            return response;
          }
          response.write(value);
          return await stream();
        };

        return await stream().catch((error) => {
          if (!response.headersSent) {
            response.status(500).send(error.message);
          } else {
            response.end();
          }
        });
      }
      if (res.headers.get("content-type")?.includes("application/json")) {
        return response.status(res.status).json(await res.json());
      }
      return response.status(res.status).send(await res.text());
    },
  });
  next();
};