From 83b60c01ef91c7d9c4107ec47d86ec0353a97cd7 Mon Sep 17 00:00:00 2001
From: "Harish.K" <harish2704@gmail.com>
Date: Mon, 21 Mar 2016 00:46:36 +0530
Subject: [PATCH] Tests passed

Featues
* Non blocking operations/Clean up synchronous codes
* handle failues
* more usefull logging
---
 app.js   | 83 ++++++++++++++++++++++++++++++++++++--------------------
 utils.js | 53 ++++++++++++++++++++++++++++++++----
 2 files changed, 101 insertions(+), 35 deletions(-)

diff --git a/app.js b/app.js
index ad9414f..df8b2d2 100644
--- a/app.js
+++ b/app.js
@@ -1,47 +1,74 @@
 var express = require('express');
-var fs = require('fs');
 var config = require( __dirname + '/./config' );
 var utils = require( __dirname + '/./utils');
 
 var NPM_PATH = config.NPM_PATH;
 var REGISTRY_NAME = config.REGISTRY_NAME;
 
+
 var fetchAndCacheMetadata = utils.fetchAndCacheMetadata;
 var fetchAndCacheTarball = utils.fetchAndCacheTarball;
 var patchData = utils.patchData;
+var fileExists = utils.fileExists;
+var readFile = utils.readFile;
 
 var app = express();
 app.use( function(req, res, next ){
-  console.log(req.method, req.path );
+  res._log = {
+    method: req.method,
+    path: req.path,
+    cacheHit: 'Hit',
+    cacheFile: '',
+  };
+
+  res.on( 'finish', function(){
+    var log = this._log;
+    console.log( log.cacheHit, this.statusCode, log.method, log.path, '    =>   ', log.cacheFile  );
+  });
+  // setTimeout( next, 1000 );
   next();
 });
 
-app.get( '/:package', function( req, res ){
+app.get( '/:package', function( req, res, next ){
   var packageName = req.params.package;
   var cacheFile = [ NPM_PATH, REGISTRY_NAME, packageName, '.cache.json' ].join( '/' );
-  var cacheData;
-
-  if( !fs.existsSync( cacheFile ) ){
-    fetchAndCacheMetadata( packageName, cacheFile );
-  }
 
-  cacheData = fs.readFileSync( cacheFile, 'utf-8' );
-  cacheData = JSON.parse( cacheData );
-
-  patchData( cacheData );
-  return res.send( cacheData );
+  return fileExists( cacheFile )
+    .tap( function( isExists ){
+      if( !isExists ){
+        res._log.cacheHit = '---';
+        return fetchAndCacheMetadata( packageName, cacheFile );
+      }
+    })
+    .then( function( ){
+      res._log.cacheFile = cacheFile;
+      return readFile( cacheFile, 'utf-8' );
+    })
+    .then( function( cacheData ){
+      cacheData = JSON.parse( cacheData );
+      patchData( cacheData );
+      return res.send( cacheData );
+    })
+    .catch( next );
 });
 
-app.get( '/:package/-/:tarball', function( req, res ){
+app.get( '/:package/-/:tarball', function( req, res, next ){
   var packageName = req.params.package;
   var version = req.params.tarball.match( new RegExp( packageName + '-(.*).tgz') )[1];
   var packagePath = [ NPM_PATH , packageName, version, 'package.tgz'].join( '/' );
 
-  if( !fs.existsSync( packagePath ) ){
-    fetchAndCacheTarball( packageName, version, packagePath );
-  }
-
-  return fs.createReadStream( packagePath ).pipe( res );
+  fileExists( packagePath )
+    .tap( function( isExists ){
+      if( !isExists ){
+        res._log.cacheHit = '---';
+        return fetchAndCacheTarball( packageName, version, packagePath );
+      }
+    })
+    .then( function(){
+      res._log.cacheFile = packagePath;
+      return res.sendFile( packagePath );
+    })
+    .catch( next );
 });
 
 
@@ -54,17 +81,15 @@ app.use(function(req, res, next) {
 
 // error handlers
 
-// development error handler
-// will print stacktrace
-if (app.get('env') === 'development') {
-  app.use(function(err, req, res, next) {
-    res.status(err.status || 500);
-    res.send({
-      message: err.message,
-      error: err
-    });
+app.use(function(err, req, res, next) {
+  console.log( err.stack );
+  res.status(err.status || 500);
+  res.send({
+    message: err.message,
+    error: err
   });
-}
+  if( next ) { next(); }
+});
 
 
 
diff --git a/utils.js b/utils.js
index 079ea55..24c9bc7 100644
--- a/utils.js
+++ b/utils.js
@@ -1,10 +1,31 @@
-var execSync = require('child_process').execSync;
 var path = require('path');
+var fs = require('fs');
 var config = require( __dirname + '/./config' );
+var Promise = require('bluebird');
+var _exec = Promise.promisify( require('child_process').exec );
 
 var REGISTRY_NAME = config.REGISTRY_NAME;
 var LOCAL_REGISTRY = config.LOCAL_REGISTRY;
 
+
+function exec( cmd, envVars ){
+  return _exec( cmd, { env: envVars });
+}
+exports.exec = exec;
+
+function fileExists( fname ){
+  return new Promise( function( resolve ){
+    fs.exists( fname, function(exists){
+      resolve( exists );
+    });
+  });
+}
+exports.fileExists = fileExists;
+
+var readFile = Promise.promisify( fs.readFile );
+exports.readFile = readFile;
+
+
 exports.patchData = function ( data ){
   Object.keys(data.versions).forEach( function( v ){
     var val = data.versions[v];
@@ -12,19 +33,39 @@ exports.patchData = function ( data ){
   });
 };
 
+var fetchAndCacheMetadataCmd =[
+  'mkdir $packageCacheDir',
+  'wget -nv "http://$REGISTRY_NAME/$packageName" -O $cacheFile || { wgetExitStatus=$? && rm $cacheFile; exit $wgetExitStatus ; }'
+].join( ';' );
+
+var  fetchAndCacheTarballCmd = [
+  'mkdir -p $packageTarballDir',
+  'wget -nv $tarballUrl -O $tarballPath || { wgetExitStatus=$? && rm $tarballPath; exit $wgetExitStatus ; }',
+  'cd $packageTarballDir; tar -xzf package.tgz package/package.json',
+].join( ';' );
+
 exports.fetchAndCacheMetadata = function ( packageName, cacheFile ){
   var packageCacheDir = path.dirname( cacheFile );
-  execSync( 'mkdir ' + packageCacheDir );
-  execSync( 'wget http://' + REGISTRY_NAME + '/' + packageName + ' -O ' + cacheFile );
+
+  return exec( fetchAndCacheMetadataCmd, {
+    packageCacheDir: packageCacheDir,
+    REGISTRY_NAME: REGISTRY_NAME,
+    packageName: packageName,
+    cacheFile: 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' );
+
+  return exec( fetchAndCacheTarballCmd, {
+    packageTarballDir: packageTarballDir,
+    tarballUrl: tarballUrl,
+    tarballPath: tarballPath,
+  });
 };
 
 
 
+