生成一个PDF文件,然后将该文件保存在本地,以验证它是否包含我期望的数据

我正在尝试生成一个PDF文件,最终我将在HTTP调用中以base64编码字符串的形式发送它,但现在我只想保存到一个文件中,以便验证内容。

通过下面的代码,我得到了一个名为 consentTest.pdf 但是当我用pdf浏览器打开它时,文件中什么都没有。

我知道PDF是正确生成的b/c当我取消注释的行 doc.pipe(fs.createWriteStream('consent1.pdf')) 在PDF生成之后,当我在PDF查看器中打开它时,它会将它与预期的内容一起保存。

'use strict'

const fs = require('fs')
const path = require('path')
const PDFDocument = require('pdfkit')

/**
 * Creates a pdf consent form to be sent as a base64encoded string
 */
function createPdfConsent() {
  let doc = new PDFDocument()
  writeContent(doc)
  // doc.pipe(fs.createWriteStream('consent1.pdf')) <-- THIS SUCCESSFULLY SAVES THE FILE WITH THE EXPECTED CONTENTS
  let file
  // Add every chunk to file
  doc.on('data', chunk => {
    if (file === undefined) {
      file = chunk
    } else {
      file += chunk
    }
  })

  // On complete, print the base64 encoded string, but also save to a file so we can verify it's contents
  doc.on('end', () => {
    const encodedFile = new Buffer(file)
    console.log('encodedFile = ', encodedFile.toString('base64'))

    // Testing printing the file back out from base64 encoding
    fs.writeFile('consentTest.pdf', encodedFile, err => {
      console.log('err = ', err)
    })
  })

  doc.end()
}

/************ Private *************

/**
 * Writes the consent content to the pdf
 * @param  {Object} doc The pdf document that we want to write to
 * @private
 */
function writeContent(doc) {
  doc.fontSize(16).text('This is the consent form', 50, 350)
}

module.exports = {
  createPdfConsent
}