Download all Google fonts using sensible FVD-style names

google_font_downloader

/*
  Script to download all google fonts and name them with FVD-based filenames
    - e.g. Rock_Salt.n4.ttf, Open_Sans.i7.ttf
*/
var https = require('https');
var http = require('http');
var fs = require('fs');
var async = require('async');

var key = 'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX'; // google fonts api server-only key
var fonts = [];
var dir = __dirname + '/fonts/google';

https.get('https://www.googleapis.com/webfonts/v1/webfonts?sort=alpha&key=' + key, function(res) {
  var out = [];
  res.on('data', function(chunk) {
    out.push(chunk);
  });
  res.on('end', function() {
    var json = JSON.parse(out.join(''));

    // only fonts with latin character support
    json.items.forEach(function(font) {
      for (var i=0; i<font.subsets.length; ++i) {
        if (font.subsets[i] == 'latin') {
          fonts.push(font);
          break;
        }
      }
    });

    // fonts = [fonts[0]]; // uncomment to debug with just one font

    // loop through each font, downloading it. max of 5 families in parallel
    async.forEachLimit(fonts, 5, function(font, callback) {
      font.variants.forEach(function(variant, i) {
        var in_file = font.files[variant];
        var out_file = fvdToFilename(googleToFvd(variant, font.family));
        console.log(out_file);
        var file = fs.createWriteStream(dir + '/' + out_file);
        var request = http.get(in_file, function(res) {
          res.pipe(file);
          res.on('end', function() {
            if (i == 0) callback(); // if i==0 otherwise async will get confused surely if multiple variants of the font
          });
        });
      });
    });

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



// functions

var googleToFvd = function(variant, family) {
  var style = variant.match(/[^0-9]+/)||'regular'; // italic, regular/normal (or oblique?)
  style = style == 'regular' ? 'n' : (style == 'italic' ? 'i' : 'o');
  var weight = variant.match(/[0-9]{1}/)||4; // variant can be e.g. 700italic or italic or 700
  return (family ? family + ':' : '') + style + weight;
};

var fvdToFilename = function(fvd) {
  return fvd.replace(':', '.').replace(/ /g, '_') + '.ttf';
}

be sure to change the 'key' to your own google fonts API key.