What to do if nodejs upload file is lost

With the development of front-end technology, more and more websites are beginning to use Node.js. Node.js, as a reliable backend framework, provides many useful features. The most common of which is uploading and downloading files. However, in some cases, uploaded files appear to be "lost". This article will introduce some possible causes of file loss and provide solutions.

1. File size limit

Many times, file size limit is the main reason for the loss of uploaded files. The default configured maximum request body size of Node.js is 100kb. If the uploaded file size exceeds 100kb, the file will be automatically discarded and an error message will be logged to the console.

Solution:

This problem can be solved in Node.js by changing the size limit of the request body. Here is sample code to achieve this using the body-parser module:

const bodyParser = require('body-parser');
const express = require('express');
const app = express();

// 设置请求体大小限制为200kb
app.use(bodyParser.json({limit: '200kb'}));

2. Upload file format

Node.js can accept any type of file upload, but sometimes There may be cases where the file format is not supported. For example, if you want to upload a file and specify the file format as .docx or .pdf, but the file format you upload is actually .txt, the uploaded file will be ignored and will not be saved.

Solution:

To resolve this issue, you need to ensure that the file you upload is in the same format as the required format. If you are not sure which format can be used, you can find it by:

const fileTypes = /docx|pdf|txt/;
const mimetype = fileTypes.test(file.mimetype);

3. Insufficient disk space

Uploaded files when your server is low on disk space may be lost. This is because insufficient disk space prevents your node server from storing file data and saving files to disk.

Solution:

To solve this problem, you can use a disk storage service such as a cloud server. Additionally, at the code level, you can write scripts to monitor disk space and send emails or other notifications when disk space is low.

4. Network connection is interrupted

If the network connection is disconnected, the uploaded files will be lost. This is because the file has not been fully uploaded, but the connection was lost causing the file to be interrupted and not saved.

Solution:

To solve this problem, you can add an error handler to catch these network disconnection situations. Following is the sample code for using error handler in Node.js:

app.use((err, req, res, next) => {
  if (err instanceof multer.MulterError) {
    // 处理Multer错误
  } else if (err) {
    // 处理其他错误
  }
});

Conclusion

Uploading files in Node.js can come with a lot of challenges that may result in the uploaded files being lost. However, these problems can be easily solved by following several methods and suggestions mentioned above. Whether it's changing the request body size limit, dealing with disk space, determining the file format, or adding an error handler, these tips will ensure your file uploads succeed.

The above is the detailed content of What to do if nodejs upload file is lost. For more information, please follow other related articles on the PHP Chinese website!