Download-Fortschritt in Node.js mit Anforderung erhalten

Question

Ich erstelle einen Updater, der Anwendungsdateien mit dem Knotenmodul request herunterlädt. Wie kann ich chunk.length verwenden, um die verbleibende Dateigröße zu schätzen? Hier ist ein Teil meiner Code:

var file_url = 'http://foo.com/bar.zip'; 
var out = fs.createWriteStream('baz.zip'); 

var req = request({ 
    method: 'GET', 
    uri: file_url 
}); 

req.pipe(out); 

req.on('data', function (chunk) { 
    console.log(chunk.length); 
}); 

req.on('end', function() { 
    //Do something 
}); 

Answer 1

Dies sollten Sie die Gesamt erhalten Sie wollen:

req.on('response', function (data) { 
    console.log(data.headers[ 'content-length' ]); 
}); 

erhalte ich eine Inhaltslänge von 9404541

Answer 2

function download(url, callback, encoding){ 
     var request = http.get(url, function(response) { 
      if (encoding){ 
       response.setEncoding(encoding); 
      } 
      var len = parseInt(response.headers['content-length'], 10); 
      var body = ""; 
      var cur = 0; 
      var obj = document.getElementById('js-progress'); 
      var total = len/1048576; //1048576 - bytes in 1Megabyte 

      response.on("data", function(chunk) { 
       body += chunk; 
       cur += chunk.length; 
       obj.innerHTML = "Downloading " + (100.0 * cur/len).toFixed(2) + "% " + (cur/1048576).toFixed(2) + " mb\r" + ".<br/> Total size: " + total.toFixed(2) + " mb"; 
      }); 

      response.on("end", function() { 
       callback(body); 
       obj.innerHTML = "Downloading complete"; 
      }); 

      request.on("error", function(e){ 
       console.log("Error: " + e.message); 
      }); 

     }); 
    }; 

Answer 3

ich ein Modul geschrieben, das gerade tut was Sie wollen: status-bar.

var bar = statusBar.create ({ total: res.headers["content-length"] }) 
    .on ("render", function (stats){ 
     websockets.send (stats); 
    }) 

req.pipe (bar); 

Answer 4

das kühle node-request-progress Modul verwenden, könnten Sie so etwas wie dies in es2015 tun:

import { createWriteStream } from 'fs' 
import request from 'request' 
import progress from 'request-progress' 

progress(request('http://foo.com/bar.zip')) 
.on('progress', state => { 

    console.log(state) 

    /* 
    { 
     percentage: 0.5,  // Overall percentage (between 0 to 1) 
     speed: 554732,   // The download speed in bytes/sec 
     size: { 
     total: 90044871,  // The total payload size in bytes 
     transferred: 27610959 // The transferred payload size in bytes 
     }, 
     time: { 
     elapsed: 36.235,  // The total elapsed seconds since the start (3 decimals) 
     remaining: 81.403  // The remaining seconds to finish (3 decimals) 
     } 
    } 
    */ 

    }) 
    .on('error', err => console.log(err)) 
    .on('end',() => {}) 
    .pipe(createWriteStream('bar.zip')) 

Answer 5

Falls jemand will den Fortschritt ohne die Verwendung von anderen Bibliothek aber nur Wunsch wissen, dann können Sie verwenden Sie die folgende Methode:

function downloadFile(file_url , targetPath){ 
    // Save variable to know progress 
    var received_bytes = 0; 
    var total_bytes = 0; 

    var req = request({ 
     method: 'GET', 
     uri: file_url 
    }); 

    var out = fs.createWriteStream(targetPath); 
    req.pipe(out); 

    req.on('response', function (data) { 
     // Change the total bytes value to get progress later. 
     total_bytes = parseInt(data.headers['content-length' ]); 
    }); 

    req.on('data', function(chunk) { 
     // Update the received bytes 
     received_bytes += chunk.length; 

     showProgress(received_bytes, total_bytes); 
    }); 

    req.on('end', function() { 
     alert("File succesfully downloaded"); 
    }); 
} 

function showProgress(received,total){ 
    var percentage = (received * 100)/total; 
    console.log(percentage + "% | " + received + " bytes out of " + total + " bytes."); 
    // 50% | 50000 bytes received out of 100000 bytes. 
} 

downloadFile("https://static.pexels.com/photos/36487/above-adventure-aerial-air.jpg","c:/path/to/local-image.jpg"); 

die received_bytes Variable die Gesamt jeder gesendeten chunk Länge speichert und entsprechend der total_bytes, die Pro Gress ist retrieven.

Answer 6

Wenn Sie „Anfrage“ Modul verwenden und wollen Prozentsatz angezeigt Download, ohne zusätzliche Modul zu verwenden, können Sie den folgenden Code verwenden:

function getInstallerFile (installerfileURL) { 

    // Variable to save downloading progress 
    var received_bytes = 0; 
    var total_bytes = 0; 

    var outStream = fs.createWriteStream(INSTALLER_FILE); 

    request 
     .get(installerfileURL) 
      .on('error', function(err) { 
       console.log(err); 
      }) 
      .on('response', function(data) { 
       total_bytes = parseInt(data.headers['content-length']); 
      }) 
      .on('data', function(chunk) { 
       received_bytes += chunk.length; 
       showDownloadingProgress(received_bytes, total_bytes); 
      }) 
      .pipe(outStream); 
}; 

function showDownloadingProgress(received, total) { 
    var percentage = ((received * 100)/total).toFixed(2); 
    process.stdout.write((platform == 'win32') ? "\033[0G": "\r"); 
    process.stdout.write(percentage + "% | " + received + " bytes downloaded out of " + total + " bytes."); 
}