您似乎正在使用node-fetch。因此，您可以执行以下操作：

// /pages/api/getAPI.js

import stream from 'stream';
import { promisify } from 'util';
import fetch from 'node-fetch';

const pipeline = promisify(stream.pipeline);
const url = 'https://w3.org/WAI/ER/tests/xhtml/testfiles/resources/pdf/dummy.pdf';

const handler = async (req, res) => {
  const response = await fetch(url); // replace this with your API call & options
  if (!response.ok) throw new Error(`unexpected response ${response.statusText}`);

  res.setHeader('Content-Type', 'application/pdf');
  res.setHeader('Content-Disposition', 'attachment; filename=dummy.pdf');
  await pipeline(response.body, res);
};

export default handler;

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然后从客户端：

// /pages/index.js

const IndexPage = () => <a href="/api/getPDF">Download PDF</a>;
export default IndexPage;

型
CodeSandbox Link（在新选项卡中打开deployed URL以查看其工作情况）
参考文献：

• API Routes | Next.js的
• 流|取节点
• How to send a pdf file from Node/Express app to the browser的
• <a>：锚元素|MDN

附言：我不认为在这种情况下有太多的错误处理是必要的。如果你想给你的用户提供更多的信息，你可以。但是这么多的代码也会很好地工作。在错误的情况下，文件下载将失败，显示“服务器错误”。此外，我不认为有必要首先创建一个blob URL。你可以直接在你的应用程序中下载它，因为API是在同一个源上。
以前的I had usedrequest，也张贴在这里，以防有人需要它：

import request from 'request';
const url = 'https://w3.org/WAI/ER/tests/xhtml/testfiles/resources/pdf/dummy.pdf';
export default (_, res) => { request.get(url).pipe(res); };

型

@brc-dd在这个问题上帮了我。我必须添加的一件事是动态生成的link元素（参见代码中的var link），一旦我们从API获得文件数据，它就会自动单击。这对于获得一致的下载非常重要（我没有事先获得）。
创建下载文件链接的页面代码如下所示：

// the fileProps variable used below looks like {"file_name":"test.png", "file_type":"image/png", "file_size": 748833}
import Button from 'react-bootstrap/Button'
import { toast } from 'react-toastify';

const DataGridCell = ({ filename, filetype, filesize }) => {
    const [objFileState, setFileDownload] = useState({})

    // handle POST request here
    useEffect(() => {
        async function retrieveFileBlob() {
            try {
                const ftch = await fetch( // this will request the file information for the download (whether an image, PDF, etc.)
                    `/api/request-file`,
                    {
                        method: "POST",
                        headers: {
                            "Content-type": "application/json"
                        },
                        body: JSON.stringify(objFileState)
                    },
                )
                const fileBlob = await ftch.blob()

                // this works and prompts for download
                var link = document.createElement('a')  // once we have the file buffer BLOB from the post request we simply need to send a GET request to retrieve the file data
                link.href = window.URL.createObjectURL(fileBlob)
                link.download = objFileState.strFileName
                link.click()
                link.remove();  //afterwards we remove the element  
            } catch (e) {
                console.log({ "message": e, status: 400 })  // handle error
            }
        }

        if (objFileState !== {} && objFileState.strFileId) retrieveFileBlob()   // request the file from our file server

    }, [objFileState])

    // NOTE: it is important that the objFile is properly formatted otherwise the useEffect will just start firing off without warning
    const objFile = {
        "objFileProps": { "file_name": filename, "file_type": filetype, "file_size": filesize }
    }
    return <Button onClick={() => {toast("File download started"); setFileDownload(objFile) }} className="btn btn-primary m-2">Download {filename}</Button>

}

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链接调用的本地NextJs API端点（/API/qualtrics/retrieve-file）如下所示：

/**
 * @abstract This API endpoint requests an uploaded file from a Qualtrics response
 * (see Qualtrics API reference for more info: 
https://api.qualtrics.com/guides/reference/singleResponses.json/paths/~1surveys~1%7BsurveyId%7D~1responses~1%7BresponseId%7D~1uploaded-files~1%7BfileId%7D/get)

 * For this API endpoint the parameters we will be:
 * Param 0 = Survey ID
 * Param 1 = Response ID
 * Param 2 = File ID
 * Param 3 = Header object (properties of the file needed to return the file to the client)
 *
 */
// This is a protected API route
import { getSession } from 'next-auth/client'

export default async function API(req, res) {
    // parse the API query
    const { params } = await req.query  // NOTE: we must await the assignment of params from the request query
    const session = await getSession({ req })
    const strSurveyId = await params[0]
    const strResponseId = await params[1]
    const strFileId = await params[2]
    const objFileProps = JSON.parse(decodeURIComponent(await params[3]))    // file properties
    // this if condition simply checks that a user is logged into the app in order to get data from this API
    if (session) {
        // ****** IMPORTANT: wrap your fetch to Qualtrics in a try statement to help prevent errors of headers already set **************
        try {
            const response = await fetch(
                `${process.env.QUALTRICS_SERVER_URL}/API/v3/surveys/${strSurveyId}/responses/${strResponseId}/uploaded-files/${strFileId}`,
                {
                    method: "get",
                    headers: {
                        "X-API-TOKEN": process.env.QUALTRICS_API_TOKEN
                    }
                }
            );

            // get the file information from the external API
            const resBlob = await response.blob();
            const resBufferArray = await resBlob.arrayBuffer();
            const resBuffer = Buffer.from(resBufferArray);
            if (!response.ok) throw new Error(`unexpected response ${response.statusText}`);

            // write the file to the response (should prompt user to download or open the file)
            res.setHeader('Content-Type', objFileProps.file_type);
            res.setHeader('Content-Length', objFileProps.file_size);
            res.setHeader('Content-Disposition', `attachment; filename=${objFileProps.file_name}`);
            res.write(resBuffer, 'binary');
            res.end();
        } catch (error) {
            return res.send({ error: `You made an invalid request to download a file ${error}`, status: 400 })
        }

    } else {
        return res.send({ error: 'You must sign in to view the protected content on this page...', status: 401 })
    }
}

型

如果您使用的是Next.js 14，并使用ImageResponse从Route Handler下载镜像文件

import { ImageResponse } from 'next/og';

export const size = {
  width: 1024,
  height: 536,
};

export async function GET() {
  try {
    // eg: APP_URL is like `https://example.com`
    const fontInterRegular = await fetch(new URL(`${process.env.APP_URL}/fonts/inter/Inter-Regular.ttf`)).then((res) =>
      res.arrayBuffer()
    );

    return new ImageResponse(
      (
        <div tw="relative h-full w-full flex items-center justify-center" style={{ fontFamily: 'Inter, Arial' }}>
          This is an image.
        </div>
      ),
      {
        headers: {
          'Content-Type': 'image/png',

          // Add this line to download the image; remember to customize the filename here.
          'Content-Disposition': `attachment; filename="this-is-downloaded-file-filename.png"`,
        },
        ...size,
        fonts: [
          {
            name: 'Inter',
            data: fontInterRegular,
            style: 'normal',
            weight: 400,
          },
        ],
      }
    );
  } catch (e: any) {
    console.log(`${e.message}`);
    return new Response(`Failed to generate the image`, {
      status: 500,
    });
  }
}

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参考资料：

• Route Handler的
• Image Response的
• Og Image Examples的