How to upload files using HTTP in Node.js_node.js

// The required modules  
var express = require('express');  
var formidable = require('formidable');  
var fs = require('fs-extra');  
var path = require('path'); 
var crypto = require('crypto');

// Serve up the Default.html page 
app.use(express.static(__dirname, { index: 'Default.html' }));  
 
// Startup the express.js application 
app.listen(process.env.PORT || 1337);  
 
// Path to save the files 
var uploadpath = 'C:/Uploads/CelerFT/';

// Use the post method for express.js to respond to posts to the uploadchunk urls and 
// save each file chunk as a separate file 
app.post('*/api/CelerFTFileUpload/UploadChunk*', function(request,response) {  
 
 if (request.method === 'POST') {  
  // Check Content-Type  
  if (!(request.is('multipart/form-data'))){  
   response.status(415).send('Unsupported media type');  
   return;  
  }  
 
  // Check that we have not exceeded the maximum chunk upload size 
  var maxuploadsize =51 * 1024 * 1024;  
 
  if (request.headers['content-length']> maxuploadsize){  
   response.status(413).send('Maximum upload chunk size exceeded');  
   return;  
  }

// Get the extension from the file name 
var extension =path.extname(request.param('filename'));  
 
// Get the base file name 
var baseFilename =path.basename(request.param('filename'), extension);  
 
// Create the temporary file name for the chunk 
var tempfilename =baseFilename + '.'+  
request.param('chunkNumber').toString().padLeft('0', 16) + extension + ".tmp";  
 
 
// Create the temporary directory to store the file chunk 
// The temporary directory will be based on the file name 
var tempdir =uploadpath + request.param('directoryname')+ '/' + baseFilename;  
 
// The path to save the file chunk 
var localfilepath =tempdir + '/'+ tempfilename;  
 
if (fs.ensureDirSync(tempdir)) {  
 console.log('Created directory ' +tempdir); 
}

// Check if we have uploaded a hand crafted multipart/form-data request 
// If we have done so then the data is sent as a base64 string 
// and we need to extract the base64 string and save it 
if (request.headers['celerft-encoded']=== 'base64') {  
 
 var fileSlice = newBuffer(+request.headers['content-length']);  
 var bufferOffset = 0;  
 
 // Get the data from the request 
 request.on('data', function (chunk) {  
  chunk.copy(fileSlice , bufferOffset);  
  bufferOffset += chunk.length;  
 }).on('end', function() {  
  // Convert the data from base64 string to binary 
  // base64 data in 4th index of the array 
  var base64data = fileSlice.toString().split('\r\n');  
  var fileData = newBuffer(base64data[4].toString(), 'base64');  
 
  fs.outputFileSync(localfilepath,fileData);  
  console.log('Saved file to ' +localfilepath);  
 
  // Send back a sucessful response with the file name 
  response.status(200).send(localfilepath);  
  response.end();  
 }); 
}

else {  
 // The data is uploaded as binary data.  
 // We will use formidable to extract the data and save it  
 var form = new formidable.IncomingForm();  
 form.keepExtensions = true;  
 form.uploadDir = tempdir;  
 
 // Parse the form and save the file chunks to the  
 // default location  
 form.parse(request, function (err, fields, files) {  
  if (err){  
   response.status(500).send(err);  
   return;  
  }  
 
 //console.log({ fields: fields, files: files });  
 });  
 
 // Use the filebegin event to save the file with the naming convention  
 /*form.on('fileBegin', function (name, file) { 
 file.path = localfilepath; 
});*/  
 
form.on('error', function (err) {  
  if (err){  
   response.status(500).send(err);  
   return;  
  }  
 });  
 
 // After the files have been saved to the temporary name  
 // move them to the to teh correct file name  
 form.on('end', function (fields,files) {  
  // Temporary location of our uploaded file    
  var temp_path = this.openedFiles[0].path;  
 
  fs.move(temp_path , localfilepath,function (err){  
 
   if (err) {  
    response.status(500).send(err);  
    return;  
   }  
   else {  
    // Send back a sucessful response with the file name  
    response.status(200).send(localfilepath);  
    response.end();  
   }  
  });  
 });  
 
// Send back a sucessful response with the file name  
//response.status(200).send(localfilepath);  
//response.end();  
} 
}

// Request to merge all of the file chunks into one file 
app.get('*/api/CelerFTFileUpload/MergeAll*', function(request,response) {  
 
 if (request.method === 'GET') {  
 
  // Get the extension from the file name 
  var extension =path.extname(request.param('filename'));  
 
  // Get the base file name 
  var baseFilename =path.basename(request.param('filename'), extension);  
 
  var localFilePath =uploadpath + request.param('directoryname')+ '/' + baseFilename;  
 
  // Check if all of the file chunks have be uploaded 
  // Note we only wnat the files with a *.tmp extension 
  var files =getfilesWithExtensionName(localFilePath, 'tmp')  
  /*if (err) { 
   response.status(500).send(err); 
   return; 
  }*/ 
 
  if (files.length !=request.param('numberOfChunks')){  
   response.status(400).send('Number of file chunks less than total count');  
   return;  
  }  
 
  var filename =localFilePath + '/'+ baseFilename +extension;  
  var outputFile =fs.createWriteStream(filename);  
 
  // Done writing the file 
  // Move it to top level directory 
  // and create MD5 hash 
  outputFile.on('finish', function (){  
   console.log('file has been written');  
   // New name for the file 
   var newfilename = uploadpath +request.param('directoryname')+ '/' + baseFilename 
   + extension;  
 
   // Check if file exists at top level if it does delete it 
   //if (fs.ensureFileSync(newfilename)) { 
   fs.removeSync(newfilename);  
   //} 
 
   // Move the file 
   fs.move(filename, newfilename ,function (err) {  
    if (err) {  
     response.status(500).send(err);  
     return;  
    }  
    else {  
     // Delete the temporary directory 
     fs.removeSync(localFilePath);  
     varhash = crypto.createHash('md5'),  
      hashstream = fs.createReadStream(newfilename);  
 
     hashstream.on('data', function (data) {  
      hash.update(data)  
     });  
 
     hashstream.on('end', function (){  
      var md5results =hash.digest('hex');  
      // Send back a sucessful response with the file name 
      response.status(200).send('Sucessfully merged file ' + filename + ", "  
      + md5results.toUpperCase());  
      response.end();  
     });  
    }  
   });  
  });  
 
  // Loop through the file chunks and write them to the file 
  // files[index] retunrs the name of the file. 
  // we need to add put in the full path to the file 
  for (var index infiles) {  
   console.log(files[index]);  
   var data = fs.readFileSync(localFilePath +'/' +files[index]);  
   outputFile.write(data);  
   fs.removeSync(localFilePath + '/' + files[index]);  
  }  
  outputFile.end();  
 } 
 
}) ;

// String padding left code taken from 
// http://www.lm-tech.it/Blog/post/2012/12/01/String-Padding-in-Javascript.aspx 
String.prototype.padLeft = function (paddingChar, length) {  
 var s = new String(this);  
 if ((this.length< length)&& (paddingChar.toString().length > 0)) {  
  for (var i = 0; i < (length - this.length) ; i++) {  
   s = paddingChar.toString().charAt(0).concat(s);  
  }  
 }  
 return s; 
} ;

<defaultDocument> 
 <files> 
  <add value="server.js" /> 
 </files> 
 </defaultDocument> 
 
 <handlers> 
 <!-- indicates that the server.js file is a node.js application to be handled by the  
 iisnode module -->  
 <add name="iisnode" path="*.js" verb="*" modules="iisnode" /> 
 </handlers> 
 
 <rewrite> 
 <rules> 
  <rule name="CelerFTJS"> 
  <match url="/*" /> 
  <action type="Rewrite" url="server.js" /> 
  </rule> 
 
  <!-- Don't interfere with requests for node-inspector debugging -->  
  <rule name="NodeInspector" patternSyntax="ECMAScript" stopProcessing="true"> 
  <match url="^server.js\/debug[\/]&#63;" /> 
  </rule> 
 </rules> 
 </rewrite>

// 使用跨域资源共享 // Taken from http://bannockburn.io/2013/09/cross-origin-resource-sharing-cors-with-a-node-js-express-js-and-sencha-touch-app/ 
var enableCORS = function(request,response, next){  
 response.header('Access-Control-Allow-Origin', '*');  
 response.header('Access-Control-Allow-Methods', 'GET,POST,OPTIONS');  
 response.header('Access-Control-Allow-Headers', 'Content-Type, Authorization, Content- 
     Length, X-Requested-With' ) ; 
 
 
 // 拦截OPTIONS方法
 if ('OPTIONS' ==request.method){  
  response.send(204);  
 }  
 else {  
  next();  
 }  
} ;  
 
// 在表达式中使用跨域资源共享
app. use ( enableCORS ) ;

// We are going to upload to a backend that supports parallel uploads. 
// Parallel uploads is supported by publishng the web site on different ports 
// The backen must implement CORS for this to work 
else if(workerdata.chunk!= null&& workerdata.paralleluploads ==true){  
 if (urlnumber >= 6) {  
  urlnumber = 0;  
 }  
 
 if (urlcount >= 6) {  
  urlcount = 0;  
 }  
 
 if (urlcount == 0) {  
  uploadurl = workerdata.currentlocation +webapiUrl + urlnumber;  
 }  
 else {  
  // Increment the port numbers, e.g 8000, 8001, 8002, 8003, 8004, 8005 
  uploadurl = workerdata.currentlocation.slice(0, -1) + urlcount +webapiUrl +  
  urlnumber;  
 }  
 
 upload(workerdata.chunk,workerdata.filename,workerdata.chunkCount, uploadurl,  
 workerdata.asyncstate);  
 urlcount++;  
 urlnumber++; 
 }