app/api/common.ts

import { NextRequest, NextResponse } from "next/server";
import { getServerSideConfig } from "../config/server";
import { DEFAULT_MODELS, OPENAI_BASE_URL } from "../constant";
import { collectModelTable, collectModels } from "../utils/model";

const serverConfig = getServerSideConfig();

export async function requestOpenai(req: NextRequest) {
 const controller = new AbortController();
 const authValue = req.headers.get("Authorization") ?? "";
 const openaiPath = `${req.nextUrl.pathname}${req.nextUrl.search}`.replaceAll(
 "/api/openai/",
 "",
 );

 let baseUrl = serverConfig.baseUrl ?? OPENAI_BASE_URL;

 if (!baseUrl.startsWith("http")) {
 baseUrl = `https://${baseUrl}`;
 }

 if (baseUrl.endsWith("/")) {
 baseUrl = baseUrl.slice(0, -1);
 }

 console.log("[Proxy] ", openaiPath);
 console.log("[Base Url]", baseUrl);
 console.log("[Org ID]", serverConfig.openaiOrgId);

 const timeoutId = setTimeout(
 () => {
 controller.abort();
 },
 10 * 60 * 1000,
 );

 const fetchUrl = `${baseUrl}/${openaiPath}`;
 const fetchOptions: RequestInit = {
 headers: {
 "Content-Type": "application/json",
 "Cache-Control": "no-store",
 Authorization: authValue,
 ...(process.env.OPENAI_ORG_ID && {
 "OpenAI-Organization": process.env.OPENAI_ORG_ID,
 }),
 },
 method: req.method,
 body: req.body,
 // to fix #2485: https://stackoverflow.com/questions/55920957/cloudflare-worker-typeerror-one-time-use-body
 redirect: "manual",
 // @ts-ignore
 duplex: "half",
 signal: controller.signal,
 };

 // #1815 try to refuse gpt4 request
 if (serverConfig.customModels && req.body) {
 try {
 const modelTable = collectModelTable(
 DEFAULT_MODELS,
 serverConfig.customModels,
 );
 const clonedBody = await req.text();
 fetchOptions.body = clonedBody;

 const jsonBody = JSON.parse(clonedBody) as { model?: string };

 // not undefined and is false
 if (modelTable[jsonBody?.model ?? ""] === false) {
 return NextResponse.json(
 {
 error: true,
 message: `you are not allowed to use ${jsonBody?.model} model`,
 },
 {
 status: 403,
 },
 );
 }
 } catch (e) {
 console.error("[OpenAI] gpt4 filter", e);
 }
 }

 try {
 const res = await fetch(fetchUrl, fetchOptions);

 // to prevent browser prompt for credentials
 const newHeaders = new Headers(res.headers);
 newHeaders.delete("www-authenticate");
 // to disable nginx buffering
 newHeaders.set("X-Accel-Buffering", "no");

 return new Response(res.body, {
 status: res.status,
 statusText: res.statusText,
 headers: newHeaders,
 });
 } finally {
 clearTimeout(timeoutId);
 }
}