如何使用lambda函数访问文件

Question

问题我最近切换到无服务器架构，无法访问我的文件下面的代码在本地环境中运行良好，但它不在 lambda 函数中执行，它给了我以下错误

它给了我以下错误

Error: ENOENT: no such file or directory, open 'tmp/file 1-1692962065917.pdf'

你能指导我如何访问 lambda 函数中的文件吗

这是我的代码

const serverless = require("serverless-http");
const express = require("express");
const multer = require('multer');
const fs = require('fs');
const { PDFDocument } = require('pdf-lib');
const http = require('http');
// const app = express();
const cors = require('cors');

const os = require('os');
const cluster = require('cluster');
const { default: e } = require('express');
const path = require('path');


// count total number of cpu
const cpuNums = os.cpus().length;
console.log("Total Number of Cpus(CORS):"+cpuNums);

var date = new Date();

const app = express();
var check=0;



app.use(cors({
  origin: '*',
}));



var fname;


// Set up multer to handle file uploads
const storage = multer.diskStorage({
  destination: (req, file, cb) => {
         cb(null, './tmp/');
  },
  filename: (req, file, cb) => {
    check++;
         fname = `${file.fieldname} ${check}-${Date.now()}.pdf`;
         console.log("Filename : "+fname);
         cb(null, fname);
  },
});

const upload = multer({ storage });



app.post('/', upload.single('file'), (req, res,next) => { console.log("=================================================");
console.log("API Last Build Date " + date.toLocaleDateString());
console.log("API Last Build  Time" + date.toLocaleTimeString());

console.log(date.getFullYear()+'-'+(date.getMonth()+1)+'-'+date.getDate());
console.log("===========================");

console.log("LAST API CALL TIME:--" + date.toLocaleString('en-US', { timeZone: 'Asia/Kolkata' }));

console.log("===========================");
console.log("Your IP Addresss is: " + req.socket.localAddress);
console.log("=================================================");
    // Read the input PDF file
    const file = req.file;
    if (!file) {
           const error = new Error("Please upload a file");
           error.httpStatusCode = 400;
           return next(error);
    }
    // crop uploaded file

    async function cropPDF(inputPath, outputPath, x, y, width, height) {
           // Read the input PDF file
           let pdfDoc = await PDFDocument.load(fs.readFileSync(inputPath));

           //   Loop through all pages in the PDF
           for (let i = 0; i < pdfDoc.getPages().length; i++) {


                  // Get the page that you want to crop
                  let page = pdfDoc.getPage(i);

                  // Set the crop box for the page
                  page.setCropBox(x, y, width, height);
           }
           // console.log();
           // Save the output PDF file
           fs.writeFileSync(outputPath, await pdfDoc.save());
           fs.unlink( './tmp/'+fname, (err) => {
                  if (err) {

                    console.error(err);


                  } else {
                    console.log('File deleted successfully');
                  }
                });


                res.download(outputPath);
           // fs.unlink();

    }

     if(req.body.Ecommerce==2)
    {

    cropPDF('./tmp/' + fname,'outputfiledownload.pdf', 170, 467, 255, 353)
           .then(() => {
                  console.log("PDF is cropped");
                  // PDF has been cropped
           })
           .catch((error) => {
                  console.log(error);
           });


    }
    });

    module.exports.handler = serverless(app);

代码总结：

我首先用户上传pdf并保存，然后根据用户选择调用函数并执行操作，然后删除文件

Answer 1

您需要将所有

./tmp

路径更改为

/tmp

。

./tmp

路径转换为“当前目录下的

tmp

文件夹”，在本例中是 Lambda 函数运行的目录。在 AWS Lambda 环境中，您无法写入 Lambda 函数运行的目录中。您只能写入

/tmp

目录。