如何在Node.js中找到文件的大小？

Question

我正在使用multer上传我的图像和文档,但这次我想限制上传,如果图像的大小> 2mb.如何找到文档文件的大小？到目前为止,我尝试如下,但没有工作.

var storage = multer.diskStorage({
      destination: function (req, file, callback) {
        callback(null, common.upload.student);
      },
      filename: function (req, file, callback) {  
        console.log(file.size+'!!!!!!!!!!!!!!')======>'Undefined'
        var ext = '';
        var name = '';
        if (file.originalname) {
          var p = file.originalname.lastIndexOf('.');
          ext = file.originalname.substring(p + 1);
          var firstName = file.originalname.substring(0, p + 1);
          name = Date.now() + '_' + firstName;
          name += ext;
        }
        var filename = file.originalname;
        uploadImage.push({ 'name': name });
        callback(null, name);
  }
});

谁能帮帮我吗？

Answer 1

var fs = require("fs"); //Load the filesystem module
var stats = fs.statSync("myfile.txt")
var fileSizeInBytes = stats["size"]
//Convert the file size to megabytes (optional)
var fileSizeInMegabytes = fileSizeInBytes / 1000000.0

要么:

function getFilesizeInBytes(filename) {
    var stats = fs.statSync(filename)
    var fileSizeInBytes = stats["size"]
    return fileSizeInBytes
}

Answer 2

If you use ES6 and deconstructing, finding the size of a file in bytes only takes 2 lines (one if the fs module is already declared!):

const fs = require('fs');
const {size} = fs.statSync('path/to/file');

Note that this will fail if the size variable was already declared. This can be avoided by renaming the variable while deconstructing using a colon:

const fs = require('fs');
const {size: file1Size} = fs.statSync('path/to/file1');
const {size: file2Size} = fs.statSync('path/to/file2');

Answer 3

另外，你可以使用 NPM filesize 包：https : //www.npmjs.com/package/filesize

这个包使事情变得更加可配置。

var fs = require("fs"); //Load the filesystem module

var filesize = require("filesize"); 

var stats = fs.statSync("myfile.txt")

var fileSizeInMb = filesize(stats.size, {round: 0});

更多示例：https :
//www.npmjs.com/package/filesize#examples