Thursday, July 17, 2014

Book Review: 'Real Time Communication with WebRTC'

I am presenting the review of the book, 'Real Time Communication with WebRTC' by Salvatore Loreto and Simon Pietro Romano.
This book is an interesting mix of both Theory and Practical components of WebRTC, better explained to a layman as Voip or skype within a browser.
One of the things that could really affect you as a reader is the way this book is written - the theoritical fundamentals are interspread with code and practical advices. At times this makes a seemingly straightforward topic like socket.io painful to understand, but this is quite handy if you are stuck at a specific problem and need to go deeper into it.
As I am already having experience in developing applications that utilize WebRTC, it was a refreshing read that also explained a lot of theory details associated with this technology and the various possible ways in which peer-to-peer audio and video can be shared on a real time basis.
To give you an overview of this book, it gives a long introduction to the users and handling of user media(mic and webcam) from a HTML5 browser, before starting the discussion of the different design strategies used in a peer-to-peer connections. It then runs the user through an application from scratch to increase his confidence over the topics discussed and finishes with a discussion of advanced features of WebRTC API.
My greatest peeve in using this book was the lack of authority in the examples - some examples failed to execute with the firefox browser. Also, some of the routinely occuring errors could have been added as this technology is constantly evolving and it is not unexpected to find some code that might not be supported by future versions of browsers.
However, the browser based peer-to-peer communication is completely discussed and this book is one of the most comprehensive text on it at the moment.
Disclaimer: I have been provided a free copy of this book by OReilly under their Blogger review program.

Tuesday, July 1, 2014

Packt Ten Year Celebration Campaign - Packt Publishing

Packt Publishing launches an exciting campaign to celebrate 10 years and is offering all eBooks and Videos at just $10 each for 10 days (Till 5th of July). 

This publication has been a boon for open source frameworks - by providing a well formed additional documentation/how-tos for a specific technology. 


Press Release:

Packt’s celebrates 10 years with a special $10 offer

This month marks 10 years since Packt Publishing embarked on its mission to deliver effective 
learning and information services to IT professionals. In that time it’s published over 2000 titles and helped projects become household names, awarding over $400,000 through its Open Source Project Royalty Scheme.

To celebrate this huge milestone, from June 26th $10 each for 10 days – this promotion covers every title and customers can stock up on as many copies as they like until July 5th Dave Maclean, Managing Director explains ‘From our very first book published back in 2004, we’ve always focused on giving IT professionals the actionable knowledge they need to get the job done. 

As we look forward to the next 10 years, everything we do here at Packt will focus on helping those IT professionals, and the wider world, put software to work in innovative new ways. 
We’re very excited to take our customers on this new journey with us, and we would like to thank them for coming this far with this special 10-day celebration, when we’ll be opening up our comprehensive range of titles for $10 each. 

If you’ve already tried a Packt title in the past, you’ll know this is a great opportunity to explore what’s new and maintain your personal and professional development. If you’re new to Packt, then now is the time to try our extensive range – we’re confident that in our 2000+ titles you’ll find the
knowledge you really need , whether that’s specific learning on an emerging technology or the key skills to keep you ahead of the competition in more established tech.’ 

More information is available at www.packtpub.com/10years 


bit.ly/1ohwJwx

Wednesday, June 25, 2014

When fast is merely not good enough

In the pursuit of applications that are having ever increasing speeds, I am constantly looking around for new ideas and have come across an interesting term, reactive programming that addresses a lot of concepts and puts the possible answer into a single umbrella; or quite simply speaking, gives it a name.
Basically, any web application under this umbrella term is people first - meaning it will inform its client what is happening instead of a delayed page load that can take anywhere between 2 seconds and hours. It always provides a real-time response to the client and responds to clients, events, load and failure.

This is typically done by making the application use following characteristics:
  1. Responsive
  2. Scalable
  3. Resilient
  4. Event-Driven

When these applications are cohesively applied, the common pattern/word that emerges gets labelled under the term reactive programming, which is promised by the http://www.reactivemanifesto.org/

Thursday, June 5, 2014

Book Review: Client Server Web Apps with Javascript and Java



The book, 'Client server Web Apps with Javascript and Java' by Casimir Saternos aply provides its puchline, 'Rich, Scalable and Restful'. These words do not only cover the essence of this book, but also describe the adoption of Javascript based frameworks and technologies on the user-interface/frontend of today's Enterprise Java applications.

A new term is used to introduce the users - Client-Server, which signifies that client side of an application is as important as its server side and the amount of programming efforts required on the client side is also as big as it is managed on the server. It is similar to the other topics that are introduced in this book - completely from scratch, which enforce learning familiar concepts like JavaScript refreshing to learn.
Even for an experienced developer, there are lot of things to watch out for like in chapter 2 where excerpts from 'Javascript: The Good Part' by Douglas Crockford are cited for concise learning. Similarly, in the next chapter detailing REST and JSON, the non-existence of url/syndication in JSON and its related debate surrounding HATEOAS (Hypermedia As The Engine Of Application State) is explained. The JVM specific languages are mentioned by highlighting build tools related to them, which is potentially confusing if the person reading is not familiar with build, version and test tools.
The next part of the book starting with Chapter 5 deals with the client side web application and quickly introduces the user towards finer points like asset pipelining and is followed up on the next chapter by introducing different JVM based servers to run and deploy the web application. Lightweight Java servers and developer productivity tools are listed in the couple of following chapters, which I think do not add much value to the overall premise of the book. The next chapter then covers the design and principals of RESTful web services and demonstrates one created in Jersy which is then followed up by jQuery.

However, the Chapter 10 covers Angular and Sinatra (a mini-web framework in ruby) which is a let down as Java8 has provided native node.js runtime through project Rhino and it would have been interesting to see angular being used in the full MEAN stack (MongoDB, Express.js, Angular.js and Node.js) as express.js is the De-facto framework in the node.js land and angular and express share quite a lot in common. That said, beginners to Angular should use this chapter to get a feel of angular and do not worry much about the choice of server side framework used to provide the RESTful service to the client side application in question. This chapter covers Angular.js in sufficient detail and covers the actual theme of the book but at the end of the chapter, as a user I am left wanting for more - especially given the multitude of client side frameworks available as of today. I will definitely keep an eye open for improvements in this chapter in the future revisions of this book.

The final three chapters deal with the packaging and deployment and touches these areas briefly - it covers just the starting pointers and the users can themselves choose the tools to learn further as they need more.
Another plus I found with this book was a well balanced Appendix - on one hand, practical examples on using different lightweight databases were given and on the other hand, various facts and trivia regarding REST was detailed.

Overall, this book is a gem of knowledge to existing/new programmers who are starting looking into the exciting world of client side javascript based webapps that interact mainly with lightweight web services.
For a few sections where a simple Java based Restful service is demonstrated, sinatra running on jRuby is created which is fine, but can potentially confuse some java programmers who are not familiar with the ruby/jruby landscape. Instead, some offshoot library of Sinatra created in Java could've been used. This apart from the smaller chapter 10 and the fact that any other client side framework and tools like grunt/bower have no mention is my main grouse from the otherwise stellar book that deserves a read for those who are starting up on new age web apps.

Disclaimer: I have been provided a free copy of this book by OReilly under their Blogger review program.

Tuesday, May 20, 2014

Recording both Audio and Video Streams from browser


This post is about the recent project that I am working on and details the approach that I have taken to circumvent an apparant problem.
I have been trying to create a web based audio+video capture tool that was using HTML5 webrtc based libraries to capture information from the user if it has a webcam and a mic. To do this task, the most robust library is RecordRTC (https://github.com/muaz-khan/WebRTC-Experiment) by Muaz Khan, which contains various examples and is actively maintained and supported by its creater.
For my requirements, I needed both audio and video streams to record at the same time, which was not coming from the usermedia object and the following code only provided a single stream of information:



I was thinking that selecting both the audio and video parameters to true would result in multiple streams or even one stream containing both the audio and video information, but I was wrong and after a detailed search, I ended up with selecting both the streams in the following function:



So, in RecordRTC we have to use the same stream object, but pass the appropriate type of stream (audio, video, gif, canvas) to choose in the library constructor, which calls the appropriate recorder, such as WhammyRecorder to record video, etc.

While stopping the recorder, similar steps are required to get the captured stream and we have to enforce a callback mechanism in the audio recording to get the video stream within the audio recording.


Currently this is supported in chrome and firefox aurora and works correctly on both the desktop as well as mobile devices out of box. But at times, the recorded audio is not in sync with the video (atleast for the first recording after each page refresh). Hopefully, this will get sorted out and this spec gets implemented in all the browsers and saves us from the problem of installing plugins like flash to use the hardware for data capture from user.