使用pdfkit生成pdf文件并将其发送到nodejs-expressjs中的浏览器 [英] Generate pdf file using pdfkit and send it to browser in nodejs-expressjs

问题描述

我正在使用pdfkit生成pdf文件，我想将此pdf文件发送到浏览器.

但我收到消息"TypeError: listener must be a function", 另外，我不需要的文件在我的父目录中生成.

有人可以解释我如何生成pdf文件并将其发送到浏览器而不将其存储在父目录中吗?
我在这里使用expressjs.

I am using pdfkit to generate pdf file and i want to send this pdf file to browser.

But i am getting message "TypeError: listener must be a function", Also, file is getting generate in my parent directory which i don't want.

Can anyone explain me how to generate pdf file and send it to browser without storing it at parent directory?
I am using expressjs here.

var PDFDocument = require('pdfkit');                      
var fs=require('fs');
doc = new PDFDocument();
doc.moveTo(300, 75)
   .lineTo(373, 301)
   .lineTo(181, 161)
   .lineTo(419, 161)
   .lineTo(227, 301)
   .fill('red', 'even-odd');  

var loremIpsum = 'Lorem ipsum dolor sit amet, consectetur adipiscing elit. Etiam in...';  

doc.y = 320;
doc.fillColor('black')
doc.text(loremIpsum, {
   paragraphGap: 10,
   indent: 20,
   align: 'justify',
   columns: 2
});  

doc.write('out.pdf');
res.download('out.pdf');

推荐答案

doc.write是引起问题的行，也是不推荐使用的方法，请不要使用它.取而代之的是，使用管道告诉您的文档在何处流式传输信息，并记住使用doc.end()将其关闭，即像这样:

doc.write is the line causing the trouble, which is also a deprecated method so don't use it. Instead, use pipe to tell your doc where to stream the information, and remember to close it using doc.end(), i.e., like so:

doc = new PDFDocument();
doc.pipe( fs.createWriteStream('out.pdf') );

// rest of the code goes here...

doc.end();

请注意，将doc.pipe()放在顶部并不重要，这对我来说很有意义(您可以将其放在doc.end()之前或之后.没关系，这样就可以了).最后，请注意，您可以使用pipe直接流式传输到响应，无需先创建文件然后下载，即:

Note that it's not important that doc.pipe() be at the top, it just makes sense to me (you can put it before or after doc.end(). It doesn't matter, it'll work just fine). Finally, note that you can use pipe to stream directly to a response, there's no need to create the file first and then download it, i.e.:

doc.pipe( fs.createWriteStream(res) )

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