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/

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.

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.

Packt celebrates International Day Against DRM today, May 6th 2014

Packt publication is celebrating International Day Against DRM today and this is a welcome sign for all the users of this ebook publisher. Personally, I've never been a fan of DRM and have always felt that it only encouraged piracy by harassing the legitimate users.

To mark this occasion, Packt Publication is showing its support for the clause by giving worthwhile discounts as mentioned in their press release:

Packt Publishing firmly believes that you should be able to read and interact with your content when you want, where you want, and how you want – to that end they have been advocates of DRM-free content since their very first eBook was published back in 2004. 
To show their continuing support for Day Against DRM, Packt Publishing is offering all its DRM-free content at $10 for 24 hours only on May 6th eBooks and Videos at www.packtpub.com. 

“Our top priority at Packt has always been to meet the evolving needs of developers 
in the most practical way possible, while at the same time protecting the hard work of our authors. DRM-free content continues to be instrumental in making that happen, providing the flexibility and freedom that is essential for an efficient and enhanced learning experience. That’s why we’ve been DRM-free from the beginning – we’ll never put limits on the innovation of our users.” 
– Dave Maclean, Managing Director

Advocates of Day Against DRM are invited to spread the word and celebrate on May 6th by exploring the full range of DRM-free content at www.packtpub.com, where all eBooks and Videos will be $10 for 24 hours.

Book Review: Agile Data Science

Agile Data Science is an instant starter guide for all things related to big data and is aimed at beginners in this technological field. It attempts to explain the technologies associated with bid data in a very simplified manner, which can be helpful to first timers but quite confusing at implementation level - mainly due to the lack of space for the topics dealt with this book.
The first half of the book talks about theory and setup of tools that can easily be setup for a data analysis project and the remaining half of the book goes into its creation.

The main point of contention I felt was the way the book shifted gears- the first section was comprehensible enough but upon moving to the second section, the level of details set in quickly, making the contents hard to follow and I ended up using the available source code.

It first starts with explaining the big data and cloud technologies prevalent today and then introduces the user towards Data, cloud and various handy tools to utilize them.

The next part contains an end to end application that mines and provides analytics for emails - a very real world implementation which is covered in various aspects.

However, as open source projects keep on changing rapidly, the relevance/best practices followed by the example is questionable. This is also important as various startups follow their individual app stacks while addressing the big data challenges.

As a personal note, I would not recommend this to a learner as a person is better off developing in bits and pieces - various tutorials over the internet serve this better. Only if you need an insight into how things are carried out to meet big data challenges using opensource technologies is this text useful.

Note: I've been provided a copy of this book under the OReilly's blogger review program.