Book Image

Mastering Node.js

By : Sandro Pasquali
Book Image

Mastering Node.js

By: Sandro Pasquali

Overview of this book

Node.js is a modern development stack focused on providing an easy way to build scalable network software. Backed by a growing number of large companies and a rapidly increasing developer base, Node is revolutionizing the way that software is being built today. Powered by Google's V8 engine and built out of C++ modules, this is a JavaScript environment for the enterprise.Mastering Node.js will take the reader deep into this exciting development environment. Beginning with a comprehensive breakdown of its innovative non-blocking evented design, Node's structure is explained in detail, laying out how its blazingly fast I/O performance simplifies the creation of fast servers, scalable architectures, and responsive web applications.Mastering Node.js takes you through a concise yet thorough tour of Node's innovative evented non-blocking design, showing you how to build professional applications with the help of detailed examples.Learn how to integrate your applications with Facebook and Twitter, Amazon and Google, creating social apps and programs reaching thousands of collaborators on the cloud. See how the Express and Path frameworks make the creation of professional web applications painless. Set up one, two, or an entire server cluster with just a few lines of code, ready to scale as soon as you're ready to launch. Move data seamlessly between databases and file systems, between clients, and across network protocols, using a beautifully designed, consistent, and predictable set of tools.Mastering Node.js contains all of the examples and explanations you'll need to build applications in a short amount of time and at a low cost, running on a scale and speed that would have been nearly impossible just a few years ago.
Table of Contents (20 chapters)
Mastering Node.js
About the Author
About the Reviewers

Parsing a file using multiple processes

One of the tasks many developers will take on is the building of a logfile processor. A logfile can be very large and many megabytes long. Any single program working on a very large file can easily run into memory problems or simply run much too slowly. It makes sense to process a large file in pieces. We're going to build a simple log processor that breaks up a big file into pieces and assigns one to each of several child workers, running them in parallel.

The entire code for this example can be found in the logproc folder of the code bundle. We will focus on the main routines:

  • Determining the number of lines in the logfile

  • Breaking those up into equal chunks

  • Creating one child for each chunk and passing it parse instructions

  • Assembling and displaying the results

To get the word count of our file, we use the wc command with child.exec as shown in the following code:

child.exec("wc -l " + filename, function(e, fL) {
  fileLength = parseInt(fL.replace(filename...