Zero byte files after XML download in node.js

Question

I have the following code snippet I am currently employing attempting to get Yahoo weather XML files:

// This script requires request libraries.
// npm install request

var fs = require('fs');
var woeid_array = fs.readFileSync('woeid.txt').toString().split("\n");
var grabWeatherFiles = function (array) {
//var http = require('http');
//var fs = require('fs');

array.forEach( 
function(element)  {
    var http = require('http');
    var file_path = 'xml/' + element + '.xml';
    console.log(file_path);
    var file = fs.createWriteStream(file_path);
    var request = http.get('http://weather.yahooapis.com/forecastrss?w=' + element, function(response) {
        response.pipe(file);

    });

});

};
grabWeatherFiles( woeid_array );

This code snippet is successful at downloading the XML files. However, if I attempt to read the files and get the XML data inside a string so I can parse it, the files are 0'd out. Is node.js not writing this correctly? This happened both on my Mac and on c9.io. Any tips would be lovely. I am quite stuck in this part.

Answer 1

You are using the wrong function. fs.writeFile takes at least three arguments filename , data and callback . You cannot pipe to it. It simply writes data to the filename and executes callback when done.

What you need is fs.createWriteStream , which takes path (apart from extra options). It creates a writeable stream, to which you can pipe into the response.

Answer 2

These are the steps I used to do the job and it works. Created a folder named xml in the same level where *.js file resides. Created woeids.txt file with some valid woeids from http://woeid.rosselliot.co.nz/lookup/london

created modified version of your code with path definition to use __dirname (useful explanation of it : What is the difference between __dirname and ./ in node.js? ) and put code in sample.js :

// This script requires request libraries.
// npm install request

var fs = require('fs');
var woeid_array = fs.readFileSync(__dirname + '/woeids.txt').toString().split("\n");
var grabWeatherFiles = function (array) {
    array.forEach( 
    function(element)  {
        var http = require('http');
        var file_path = __dirname + '/xml/' + element + '.xml';
        console.log(file_path);
        var file = fs.createWriteStream(file_path);
        var request = http.get('http://weather.yahooapis.com/forecastrss?w=' + element, function(response) {
            response.pipe(file);

        });

    });
};
grabWeatherFiles( woeid_array );

Run it through terminal node sample.js and it populated the xml folder with the proper xml files.