Question

我目前正在学习 puppeteer 和 firebase。我想要做的是创建网页的 pdf 并上传到 firebase 存储。这是我的代码。

const puppeteer = require('puppeteer');
const fs = require('fs').promises;
const firebase = require('firebase');
require("firebase/storage");

const url = process.argv[2];
if (!url) {
    throw "Please provide URL as a first argument";
}

var firebaseConfig = {
        #Firebase Config Goes here
  };
  // Initialize Firebase
  firebase.initializeApp(firebaseConfig);


#Function to generate PDF file
async function run () {
    const browser = await puppeteer.launch();
    const page = await browser.newPage();

    //await page.goto(url);
    await page.goto(url, {waitUntil: 'domcontentloaded', timeout: 60000} );

    //await page.pdf({ path: 'api.pdf', format: 'A4' })

    const myPdf = await page.pdf();
    
     await browser.close()

     return myPdf;
}

const myOutput = run();

#Upload to Firebase based on the instruction here https://firebase.google.com/docs/storage/web/upload-files
 
var storageRef = firebase.storage().ref();
// Create a reference to 'mountains.jpg'
storageRef.child("Name.pdf").put(myOutput)

但是，我在执行代码时遇到了这个错误

$ node screenshot.js https://google.com
Promise { <pending> }
(node:20636) UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'byteLength' of undefined
    at C:\Users\ppham\NucampFolder\Test\node_modules\@firebase\storage\dist\index.cjs.js:833:40
    at Array.forEach (<anonymous>)
    at Function.FbsBlob.getBlob (C:\Users\ppham\NucampFolder\Test\node_modules\@firebase\storage\dist\index.cjs.js:832:25)
    at multipartUpload (C:\Users\ppham\NucampFolder\Test\node_modules\@firebase\storage\dist\index.cjs.js:1519:24)
    at C:\Users\ppham\NucampFolder\Test\node_modules\@firebase\storage\dist\index.cjs.js:2003:31
    at C:\Users\ppham\NucampFolder\Test\node_modules\@firebase\storage\dist\index.cjs.js:1900:21
    at processTicksAndRejections (internal/process/task_queues.js:85:5)
(node:20636) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:20636) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

这似乎暗示 myOutput 不包含任何内容。我以为我在执行 run() 函数后创建了 pdf 文件，将其分配给 myOutput 变量并将其传递给上传函数？我一直在阅读 Puppeteer 文档，但找不到任何不起作用的原因。有人知道为什么这是无效的吗？

Answer 1

例如，您的代码与 https://www.toptal.com/puppeteer/headless-browser-puppeteer-tutorial 处的示例代码之间的区别是微不足道的，但有一个显着区别：

run 被定义为一个 async 函数——在示例代码中，这可能无关紧要，因为示例的最后一行只调用了 run()，之后没有任何反应。但是，在您的代码中，您希望对该输出执行某些操作。所以，你需要调用它：

const myOutput = await run();

但是，Node 不希望您在顶层使用 await - await 只能在 async 函数内使用。因此，您可以使用 then() 或仅定义另一个异步包装器。所以，大概是这样的：

async function runAndUpload() {
    const myOutput = await run();
    console.log(myOutput); //let's make sure there's output
    var storageRef = firebase.storage().ref();
    storageRef.child("Name.pdf").put(myOutput)
}

runAndUpload();

生成 PDF 文件以上传到 firebase 时遇到问题

1 个答案: