Question

I’m trying to download and require a .js file using a node.js script, but only part of the file is being downloaded.

Specifically, this is the part that seems to be causing the problem:

response.on('data', function (chunk) {
    out.write(chunk);
    var theModule = require(__dirname + "/" + filename);
    //less than half of the file is downloaded when the above line is included.
});

Here is the full source code:

var http = require('http');
var fs = require('fs');

downloadModule("functionChecker.js");

function downloadModule(filename) {
    var google = http.createClient(80, 'www.google.com');
    var request = google.request('GET', '/svn/' + filename, {
        'host': 'javascript-modules.googlecode.com'
    });
    request.end();
    out = fs.createWriteStream(filename);
    request.on('response', function (response) {
        response.setEncoding('utf8');
        response.on('data', function (chunk) {
            out.write(chunk);
            var theModule = require(__dirname + "/" + filename);
            //less than half of the file is downloaded when the above line is included.
            //If the import statement is omitted, then the file is downloaded normally.
        });
    });
}

Answer 1

The data event can be called multiple times. You need to wait until all of the data is written.

response.setEncoding('utf8');
response.on('data', function (chunk) {
    out.write(chunk);
});
response.on('end', function(){
    out.end();
    var theModule = require(__dirname + "/" + filename);
});

Also, createClient is deprecated, as mentioned in the docs. I’d also recommend using pipe to simplify your logic.

function downloadModule(filename) {
  http.get({
    hostname: 'javascript-modules.googlecode.com',
    path: '/svn/' + filename
  }, function(res){
    var out = fs.createWriteStream(filename);
    out.on('close', function(){
      var theModule = require(__dirname + "/" + filename);
    });

    res.pipe(out);
  });
}