响应来自缓冲区的文件，请求两次要下载

发布于 2025-02-09 03:11:52 字数 604 浏览 2 评论 0原文

我有一个Express Nodejs服务器，该服务器可以进行一些计算并创建PDF文件并将其作为响应发送。问题是，当用户试图下载文件时，端点被浏览器两次调用，因此计算完成了两次，并且需要两倍的时间，并且要回答请求大约需要20秒。我检查了一下，发现终点本身被称为两次不是favicon.ico或其他东西。

该文件未保存在服务器上，并以缓冲区的形式创建，然后将其管道输送到客户端。端点不是由前端代码调用，也不会由某物提取，它只是在浏览器的新选项卡中打开。下面列出了一些代码：

let buffer =  await createPdfBuffer() // a custom function that creates the pdf as buffer
const readStream = new stream.PassThrough();

readStream.end(buffer);
res.set('Content-disposition', 'attachment; filename=' + file.pdf);
res.set('Content-Type', 'application/pdf');
readStream.pipe(res);

原文

I have an express nodejs server which does some calculations and creates a pdf file and sends it as the response. The problem is, when the user tries to download the file, the endpoint is called twice by the browser so the calculations are done twice and it will take twice as long and it will take around 20 seconds for the request to be answered. I checked and saw that the endpoint itself is called twice not favicon.ico or other things.

The file is not saved on the server and is created as buffer and then piped to the client. The endpoint is not called by the frontend code or fetched by something, it is just opened in a new tab in the browser. Some of the code is listed below:

let buffer =  await createPdfBuffer() // a custom function that creates the pdf as buffer
const readStream = new stream.PassThrough();

readStream.end(buffer);
res.set('Content-disposition', 'attachment; filename=' + file.pdf);
res.set('Content-Type', 'application/pdf');
readStream.pipe(res);

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