Question

79

Node: Downloading a zip through Request, Zip being corrupted

rated 0 times [ 81] [ 2] / answers: 1 / hits: 31704 / 12 Years ago, sun, august 19, 2012, 12:00:00

I'm using the excellent Request library for downloading files in Node for a small command line tool I'm working on. Request works perfectly for pulling in a single file, no problems at all, but it's not working for ZIPs.

For example, I'm trying to download the Twitter Bootstrap archive, which is at the URL:

http://twitter.github.com/bootstrap/assets/bootstrap.zip

The relevant part of the code is:

var fileUrl = http://twitter.github.com/bootstrap/assets/bootstrap.zip;

var output = bootstrap.zip;

request(fileUrl, function(err, resp, body) {

  if(err) throw err;

  fs.writeFile(output, body, function(err) {

    console.log(file written!);

  }

}

I've tried setting the encoding to binary too but no luck. The actual zip is ~74KB, but when downloaded through the above code it's ~134KB and on double clicking in Finder to extract it, I get the error:

Unable to extract bootstrap into nodetest (Error 21 - Is a directory)

I get the feeling this is an encoding issue but not sure where to go from here.

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briarc

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3 Years ago

answered 12 Years ago marib · Accepted Answer

Yes, the problem is with encoding. When you wait for the whole transfer to finish body is coerced to a string by default. You can tell request to give you a Buffer instead by setting the encoding option to null:

var fileUrl = http://twitter.github.com/bootstrap/assets/bootstrap.zip;

var output = bootstrap.zip;

request({url: fileUrl, encoding: null}, function(err, resp, body) {

  if(err) throw err;

  fs.writeFile(output, body, function(err) {

    console.log(file written!);

  });

});

Another more elegant solution is to use pipe() to point the response to a file writable stream:

request('http://twitter.github.com/bootstrap/assets/bootstrap.zip')

  .pipe(fs.createWriteStream('bootstrap.zip'))

  .on('close', function () {

    console.log('File written!');

  });

A one liner always wins :)

pipe() returns the destination stream (the WriteStream in this case), so you can listen to its close event to get notified when the file was written.