使用 pdfkit 生成 PDF

Question

我正在更改有关用户创建和下载 pdf 的网站配置。这里的想法是，pdf 是根据数据库中的数据创建的，并且不存储，而是直接提供给用户下载。 原始网站使用的是 html-pdf，但我无法成功安装它，因为我总是遇到 phantomjs、phantomjs-prebuilt 等问题。 我尝试使用 pdfkit，但没有成功，而且由于我经验不足，所以这个问题肯定是我不太明白的。

有人可以给我一些指点吗？

let     express             = require('express'),
        router              = express.Router(),
        asyncMiddleware     = require('../utils/asyncMiddleware'),
        auth                = require('../middleware/authentication'),
        // pdf                 = require('html-pdf'),
        blobStream          = require('blob-stream'),
        pdf                 = require('pdfkit'),
        juice               = require('juice'),
        {User, Report}      = require('../models');







router.get('/:reportId?', auth.isLoggedIn, asyncMiddleware( async(req, res) => {

    let reqUser = req.user;
    //get the report
    let report = await Report.findById( req.params.reportId ).populate('ownerManagerId');
    
    if( !report ) {
        req.flash('error', req.__('flash.error.reportNotFound') );
        return res.redirect('back');
    }

    //check if user on the request is the user of the report or is the group admin stored when the report was generated 
    if(  !reqUser._id.equals(report.ownerId) && !reqUser._id.equals(report.ownerManagerId) && req.user.role !=="admin" ){
        req.flash('error', req.__('flash.error.forbiddenAccess') );
        return res.redirect('back');
    }
   
    //report data
    let data = {
        layout: 'pdf_layout',
        styles: [],
        scripts: [],
        user: reqUser,
        lang: req.lang,
        pageTitle: req.__('pageTitle-calculator-report'),
        reportOwnerManager: report.ownerManagerId,
        reportDate: formatDateInReport( report.createdAt ),
        calcData: report.inputs,
        output: report.outputs
    }

    //add some helper functions to ejs views
    res.locals.formatNum = formatNum;
    res.locals.findInputCorr = findInputCorr;
   
    res.render('calculadora/relatorioPdf', data, (err1, html)=>{
        if(err1) return res.send(err1);
        //inline all css on html
        let inlineHtml = juice(html);
        
        //set pdf options
        var pdfOptions = { 
            width: "297mm",
            height: "420mm",        // allowed units: mm, cm, in, px
            //format: "A4",        // allowed units: A3, A4, A5, Legal, Letter, Tabloid
            //orientation: "portrait",
            border: {
                top: "30mm",            // default is 0, units: mm, cm, in, px
                right: "20mm",
                bottom: "0",
                left: "20mm"
            }
        };

        // //create the pdf and stream it to response   
        // pdf.create(inlineHtml, pdfOptions).toStream( (err2, stream)=>{
        //     if(err2) return res.send(err2);
        //     //set headers so the file is downloaded instead of shown in browser
        //     res.writeHead(200, {
        //         'Content-Type': 'application/pdf',
        //         'Content-disposition': `attachment; filename=relatorio-${report.id}.pdf`
        //     });
        //     //redirect stream to response
        //     stream.pipe(res);
        // });

        //set headers so the file is downloaded instead of shown in browser
        const stream = res.write(200, {
            'Content-Type': 'application/pdf',
            'Content-disposition': `attachment; filename=relatorio-${report.id}.pdf`
        });

        buildPDF(
            (chunk) => stream.write(chunk),
            () => stream.end()
        );


        function buildPDF() {
            const doc = new pdf();
            doc.on('data', dataCallback);
            doc.end('data', endCallback);
            doc.pipe(res);
            doc.end();
        }
    });//render

}))//get´´´