如何使用expressnodejs上传图像文件并进行显示

how to upload image file and display using express nodejs

本文关键字：显示 文件 图像 何使用 expressnodejs      更新时间：2024-02-29

我使用了以下代码：

fileupload.html

<html>
<head>
<title>File Uploading Form</title>
</head>
<body>
<h3>File Upload:</h3>
Select a file to upload: <br />
<form action="http://127.0.0.1:8081/file_upload" method="POST" enctype="multipart/form-data">
<input type="file" name="file" size="50" />
<br />
<input type="submit" value="Upload File" />
</form>
</body>
</html>

fileupload.js:

var express = require('express');
var app = express();
var fs = require("fs");
var bodyParser = require('body-parser');
var multer  = require('multer');
//console.log(multer);
app.use(express.static('public'));
app.use(bodyParser.urlencoded({ extended: false }));
app.use(multer({ dest: '/tmp/'}));
app.get('/fileupload.html', function (req, res) {
   res.sendFile( __dirname + "/" + "fileupload.html" );
})
app.post('/file_upload', function (req, res) {
   console.log(req.files.file.name);
   console.log(req.files.file.path);
   console.log(req.files.file.type);
   var file = __dirname + "/" + req.files.file.name;
   fs.readFile( req.files.file.path, function (err, data) {
        fs.writeFile(file, data, function (err) {
         if( err ){
              console.log( err );
         }else{
               response = {
                   message:'File uploaded successfully',
                   filename:req.files.file.name
              };
          }
          console.log( response );
          res.end( JSON.stringify( response ) );
       });
   });
})
var server = app.listen(8081, function () {
  var host = server.address().address
  var port = server.address().port
  console.log("Example app listening at http://%s:%s", host, port)
})

我已经使用了上面的代码来上传文件，但当在终端中使用节点fileupload.js执行时，我得到类型错误TypeError('app.use() requires middleware functions');

谁能帮我解决这个问题吗。

您正在尝试使用multer的旧API。它在一段时间前发生了变化，有关更多信息，请参阅文档。

在您上传单个文件的特定情况下，您将删除app.use(multer({ ... }))行，而使用.single()和req.file，如：

var upload = multer({ dest: '/tmp/'});
// File input field name is simply 'file'
app.post('/file_upload', upload.single('file'), function(req, res) {
  var file = __dirname + '/' + req.file.filename;
  fs.rename(req.file.path, file, function(err) {
    if (err) {
      console.log(err);
      res.send(500);
    } else {
      res.json({
        message: 'File uploaded successfully',
        filename: req.file.filename
      });
    }
  });
});

Multer向请求对象添加一个body对象和一个或多个file对象。body对象包含表单文本字段的值，file或files对象包含通过表单上传的文件。

使用此代码，希望这将对您有所帮助。

var express = require('express');
var app = express();
var fs = require("fs");
var bodyParser = require('body-parser');
var multer = require('multer');
app.use(express.static('public'));
app.use(bodyParser.urlencoded({ extended: false }));
var upload = multer({ dest: '/tmp' })
app.get('/fileupload.html', function (req, res) {
   res.sendFile( __dirname + "/" + "fileupload.html" );
})
app.post('/file_upload', upload.single("file"), function (req, res) {
   var file = __dirname + "/" + req.file.originalname;
   fs.readFile( req.file.path, function (err, data) {
        fs.writeFile(file, data, function (err) {
         if( err ){
              console.error( err );
              response = {
                   message: 'Sorry, file couldn''t be uploaded.',
                   filename: req.file.originalname
              };
         }else{
               response = {
                   message: 'File uploaded successfully',
                   filename: req.file.originalname
              };
          }
          res.end( JSON.stringify( response ) );
       });
   });
})
var server = app.listen(8081, function () {
  var host = server.address().address
  var port = server.address().port
  console.log("Example app listening at http://%s:%s", host, port)
})

上面的解决方案对我不起作用，所以我使用了存储方法：

var express = require('express');
var app = express();
var fs = require("fs");
var bodyParser = require('body-parser');
var multer  = require('multer');
app.use(express.static('public'));
app.use(bodyParser.urlencoded({ extended: false }));
app.get('/index.htm', function (req, res) {
    res.sendFile( __dirname + "/" + "index.htm" );
})

var storage = multer.diskStorage({
    destination: function (req, file, cb) {
        cb(null, './uploads/')
    },
    filename: function (req, file, cb) {
        var ext = require('path').extname(file.originalname);
        ext = ext.length>1 ? ext : "." + require('mime').extension(file.mimetype);
        require('crypto').pseudoRandomBytes(16, function (err, raw) {
            cb(null, (err ? undefined : raw.toString('hex') ) + ext);
        });
    }
});
var upload = multer({ storage: storage });
app.post('/file_upload', upload.any(), function (req, res, next) {
    res.send(req.files);
})

它对我来说是正确的

var express = require('express'),
    http = require('http'),
    formidable = require('formidable'),
    fs = require('fs'),
    path = require('path');
var bodyParser = require('body-parser');
var multer  = require('multer');
var upload = multer({ dest: '/tmp/'});
var app = express();
app.get('/', function(req, res) {
  res.sendFile(path.join(__dirname + '/index.html'));
});
var server = app.listen(3000, function() {
  console.log('leistening on port', server.address().port);
})
app.post('/upload', upload.single('file'), function(req, res) {
  var file = 'uploads' + '/' + req.file.originalname;
  fs.rename(req.file.path, file, function(err) {
    if (err) {
      res.send(500);
    } else {
      res.json({
        message: 'File uploaded successfully',
        filename: req.originalname
      });
    }
  });
});
<!DOCTYPE html>
<!--[if lt IE 7]>      <html class="no-js lt-ie9 lt-ie8 lt-ie7"> <![endif]-->
<!--[if IE 7]>         <html class="no-js lt-ie9 lt-ie8"> <![endif]-->
<!--[if IE 8]>         <html class="no-js lt-ie9"> <![endif]-->
<!--[if gt IE 8]><!--> <html class="no-js"> <!--<![endif]-->
    <head>
        <meta charset="utf-8">
        <meta http-equiv="X-UA-Compatible" content="IE=edge">
        <title></title>
        <meta name="description" content="">
        <meta name="viewport" content="width=device-width, initial-scale=1">
        <link rel="stylesheet" href="">
    </head>
    <body>
            <form action="http://127.0.0.1:3000/upload" enctype="multipart/form-data" method="post">
                <input type="text" name="title">
                <input type="file" name="file">
                <input type="submit" value="Upload">
            </form>
    </body>
</html>

保留原始文件名或扩展名似乎不安全，我发现/制作了这段代码，通过在文件url:中添加.jpg来直接在各处显示图像

restapi.get('/uploads/:id', function (req, res) {
  var storedMimeType = 'image/jpeg';
  res.setHeader('Content-Type', storedMimeType)
 fs.createReadStream(path.join('./uploads/', req.params.id).replace(/'.[^/.]+$/, "")).pipe(res)
})
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