ChatGPT-Next-Web/app/api/anthropic.ts

import type { NextRequest } from 'next/server';
import { getServerSideConfig } from '@/app/config/server';
import {
  Anthropic,
  ANTHROPIC_BASE_URL,
  ApiPath,
  ModelProvider,
  ServiceProvider,
} from '@/app/constant';
import { cloudflareAIGatewayUrl } from '@/app/utils/cloudflare';
import { prettyObject } from '@/app/utils/format';
import { isModelAvailableInServer } from '@/app/utils/model';
import { NextResponse } from 'next/server';
import { auth } from './auth';

const ALLOWD_PATH = new Set([Anthropic.ChatPath, Anthropic.ChatPath1]);

export async function handle(
  req: NextRequest,
  { params }: { params: { path: string[] } },
) {
  console.log('[Anthropic Route] params ', params);

  if (req.method === 'OPTIONS') {
    return NextResponse.json({ body: 'OK' }, { status: 200 });
  }

  const subpath = params.path.join('/');

  if (!ALLOWD_PATH.has(subpath)) {
    console.log('[Anthropic Route] forbidden path ', subpath);
    return NextResponse.json(
      {
        error: true,
        msg: `you are not allowed to request ${subpath}`,
      },
      {
        status: 403,
      },
    );
  }

  const authResult = auth(req, ModelProvider.Claude);
  if (authResult.error) {
    return NextResponse.json(authResult, {
      status: 401,
    });
  }

  try {
    const response = await request(req);
    return response;
  } catch (e) {
    console.error('[Anthropic] ', e);
    return NextResponse.json(prettyObject(e));
  }
}

const serverConfig = getServerSideConfig();

async function request(req: NextRequest) {
  const controller = new AbortController();

  const authHeaderName = 'x-api-key';
  const authValue
    = req.headers.get(authHeaderName)
    || req.headers.get('Authorization')?.replaceAll('Bearer ', '').trim()
    || serverConfig.anthropicApiKey
    || '';

  const path = `${req.nextUrl.pathname}`.replaceAll(ApiPath.Anthropic, '');

  let baseUrl
    = serverConfig.anthropicUrl || serverConfig.baseUrl || ANTHROPIC_BASE_URL;

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

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

  console.log('[Proxy] ', path);
  console.log('[Base Url]', baseUrl);

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

  // try rebuild url, when using cloudflare ai gateway in server
  const fetchUrl = cloudflareAIGatewayUrl(`${baseUrl}${path}`);

  const fetchOptions: RequestInit = {
    headers: {
      'Content-Type': 'application/json',
      'Cache-Control': 'no-store',
      'anthropic-dangerous-direct-browser-access': 'true',
      [authHeaderName]: authValue,
      'anthropic-version':
        req.headers.get('anthropic-version')
        || serverConfig.anthropicApiVersion
        || Anthropic.Vision,
    },
    method: req.method,
    body: req.body,
    redirect: 'manual',
    // @ts-ignore
    duplex: 'half',
    signal: controller.signal,
  };

  // #1815 try to refuse some request to some models
  if (serverConfig.customModels && req.body) {
    try {
      const clonedBody = await req.text();
      fetchOptions.body = clonedBody;

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

      // not undefined and is false
      if (
        isModelAvailableInServer(
          serverConfig.customModels,
          jsonBody?.model as string,
          ServiceProvider.Anthropic as string,
        )
      ) {
        return NextResponse.json(
          {
            error: true,
            message: `you are not allowed to use ${jsonBody?.model} model`,
          },
          {
            status: 403,
          },
        );
      }
    } catch (e) {
      console.error(`[Anthropic] filter`, e);
    }
  }
  // console.log("[Anthropic request]", fetchOptions.headers, req.method);
  try {
    const res = await fetch(fetchUrl, fetchOptions);

    // console.log(
    //   "[Anthropic response]",
    //   res.status,
    //   "   ",
    //   res.headers,
    //   res.url,
    // );
    // 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);
  }
}