More advanced features.

* fetch data from main registry if cache look up is failed
* save fetched data to npm's cache, in same was as npm does the job

app.js

@@ -1,21 +1,16 @@
 var express = require('express');
 var fs = require('fs');
+var config = require( __dirname + '/./config' );
+var utils = require( __dirname + '/./utils');
 
-var NPM_PATH = process.env.HOME + '/.npm';
+var NPM_PATH = config.NPM_PATH;
-var REGISTRY_NAME = 'registry.npmjs.org';
+var REGISTRY_NAME = config.REGISTRY_NAME;
-var LOCAL_REGISTRY = 'localhost:8080';
 
+var fetchAndCacheMetadata = utils.fetchAndCacheMetadata;
+var fetchAndCacheTarball = utils.fetchAndCacheTarball;
+var patchData = utils.patchData;
 
 var app = express();
-
-function patchData( data ){
-  Object.keys(data.versions).forEach( function( v ){
-    var val = data.versions[v];
-    val.dist.tarball = val.dist.tarball.replace( REGISTRY_NAME, LOCAL_REGISTRY );
-  });
-}
-
-
 app.use( function(req, res, next ){
   console.log(req.method, req.path );
   next();
@@ -24,7 +19,13 @@ app.use( function(req, res, next ){
 app.get( '/:package', function( req, res ){
   var packageName = req.params.package;
   var cacheFile = [ NPM_PATH, REGISTRY_NAME, packageName, '.cache.json' ].join( '/' );
-  var cacheData = fs.readFileSync( cacheFile, 'utf-8' );
+  var cacheData;
+
+  if( !fs.existsSync( cacheFile ) ){
+    fetchAndCacheMetadata( packageName, cacheFile );
+  }
+
+  cacheData = fs.readFileSync( cacheFile, 'utf-8' );
   cacheData = JSON.parse( cacheData );
 
   patchData( cacheData );
@@ -35,6 +36,11 @@ app.get( '/:package/-/:packageName-:version.tgz', function( req, res ){
   var packageName = req.params.package;
   var version = req.params.version.split('-').pop();
   var packagePath = [ NPM_PATH , packageName, version, 'package.tgz'].join( '/' );
+
+  if( !fs.existsSync( packagePath ) ){
+    fetchAndCacheTarball( packageName, version, packagePath );
+  }
+
   return fs.createReadStream( packagePath ).pipe( res );
 });
 

bin/www

@@ -5,7 +5,6 @@
  */
 
 var app = require('../app');
-var debug = require('debug')('npm-proxy:server');
 var http = require('http');
 
 /**
@@ -86,5 +85,5 @@ function onListening() {
   var bind = typeof addr === 'string'
     ? 'pipe ' + addr
     : 'port ' + addr.port;
-  debug('Listening on ' + bind);
+  console.log('Listening on ' + bind);
 }

config.js

@@ -0,0 +1,15 @@
+
+var defaultConfig = {
+  NPM_PATH       : process.env.HOME + '/.npm',
+  REGISTRY_NAME  : 'registry.npmjs.org',
+  LOCAL_REGISTRY : 'localhost:8080',
+};
+
+var config = {};
+
+Object.keys( defaultConfig ).forEach( function(v){
+  config[v] = process.env[v] || defaultConfig[v];
+});
+
+module.exports = config;
+

test/utils.spec.js

@@ -0,0 +1,32 @@
+/* globals describe, it */
+
+var utils = require( '../utils' );
+var assert = require('assert');
+var fs = require('fs');
+var path = require('path');
+
+
+var fetchAndCacheMetadata = utils.fetchAndCacheMetadata;
+var fetchAndCacheTarball = utils.fetchAndCacheTarball;
+
+/* TODO: write test */
+// var patchData = utils.patchData;
+
+
+describe( 'Utility functions ', function(){
+
+  it.skip( 'should fetchAndCacheMetadata', function( ){
+    var cacheFile = '/home/hari/.npm/registry.npmjs.org/lodash/.cache.json';
+    fetchAndCacheMetadata( 'lodash', cacheFile );
+    assert( fs.existsSync( cacheFile ) );
+  });
+
+  it( 'should fetchAndCacheTarball', function(){
+    var cacheFile = '/home/hari/.npm/lodash/4.2.1/package.tgz';
+    var packageJsonFile =  path.dirname( cacheFile ) + '/package/package.json';
+
+    fetchAndCacheTarball( 'lodash', '4.2.1', cacheFile );
+    assert( fs.existsSync( cacheFile ) );
+    assert( fs.existsSync( packageJsonFile ) );
+  });
+});

utils.js

@@ -0,0 +1,30 @@
+var execSync = require('child_process').execSync;
+var path = require('path');
+var config = require( __dirname + '/./config' );
+
+var REGISTRY_NAME = config.REGISTRY_NAME;
+var LOCAL_REGISTRY = config.LOCAL_REGISTRY;
+
+exports.patchData = function ( data ){
+  Object.keys(data.versions).forEach( function( v ){
+    var val = data.versions[v];
+    val.dist.tarball = val.dist.tarball.replace( REGISTRY_NAME, LOCAL_REGISTRY );
+  });
+};
+
+exports.fetchAndCacheMetadata = function ( packageName, cacheFile ){
+  var packageCacheDir = path.dirname( cacheFile );
+  execSync( 'mkdir ' + packageCacheDir );
+  execSync( 'wget http://' + REGISTRY_NAME + '/' + packageName + ' -O ' + cacheFile );
+};
+
+exports.fetchAndCacheTarball = function ( packageName, version, tarballPath ){
+  var tarballUrl = 'http://' + REGISTRY_NAME + '/' + packageName + '/-/' + packageName + '-' + version + '.tgz';
+  var packageTarballDir = path.dirname( tarballPath );
+  execSync( 'mkdir -p ' + packageTarballDir );
+  execSync( 'wget ' + tarballUrl + ' -O ' + tarballPath );
+  execSync( 'cd ' + packageTarballDir + ';tar -xzf package.tgz package/package.json' );
+};
+
+
+