使用node.js下载PDF会导致文件损坏

Question

I am trying to download a number of PDF files from list (var urls) which contains the URLs. The download itself works but the resutlting PDF files are broken, meaning I can save them in my folder but I cannot open them. Is there anyone who has an idea? Here is the code:

var urls=require('./paperURLs.json');
DOWNLOAD_DIR = './paper/';

function readFile(callback) {
  if(urls.length > 0) {
     var setFile = urls.shift(),
     file_name = url.parse(setFile).pathname.split('/').pop(),
     trial = setFile.split('/').pop(),
     file = fs.createWriteStream(DOWNLOAD_DIR + trial);
     http.get(setFile, function(res){
         res.on('error', function(err){
            console.log(err);
        });
        res.on('data', function(data){
            file.write(data);
            console.log(setFile + ' started');
        });
        res.on('end', function(){ 
            console.log(setFile + ' completed, moving on');
            readFile(callback);
        });
    });
  } 
}

 readFile();

Thanks in advance for your help.

Answer 1

One issue is that you're not closing the file, which could cause some problems. Also, a better/easier way to do this might be to just pipe the streams together instead of doing it manually:

http.get(setFile, function(res) {
  res.on('error', function(err) {
    console.log(err);
  });
  res.pipe(file).on('close', function() {
    console.log(setFile + ' completed, moving on');
    readFile(callback);
  });
});