Category Archives: Uncategorized

Reverse engineering using Slick 3.2 and Scala


Knoldus

Sometime, we have requirements for create classes corresponding to the existing database or Sometimes, in our initial phase of project, we are going to design database and tables first, after that, we are going to create classes for mapping our tables.

As we know, Slick is a FRM(Functional Relational Mapping) for scala. Its a kind of ORM but for scala, it supports Functional and Reactive programming supports. Like in my Java experience with Hibernate, we are mostly use Jboss tools for reverse engineering from database tables to JavaPojo classes or Entities, Or While we are using JOOQ , JOOQ also provide some plugins for generate the code corresponding to tables.  Like, same as Hibernate, JOOQ and many more, Slick also provide a way for create classes corresponding to database tables by using Schema Code Generation.  Below are simple steps for generate scala…

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Internationalization with Play Framework(2.6.x)


Knoldus


In this blog, I will demonstrate how your application can support different languages using Play Framework 2.6.0 
 
What is Application/Website Internationalization ?
 
Application/Website Internationalization can be defined as a process of developing and designing an application that supports not only single language but also different languages so that it can be easily adapted by the users from any language, region, or geography. It ensures that the code base of your application is flexible enough to serve a new audience without rewriting the complete code or keeps text separate from the code base. 
 
Let us start the implementation step by step:
 
1. Specifying Languages for your application  
  
In order to specify Languages for your application, you need Language tags, which are specially formatted strings that indicate specific languages such as “en” for English, “fr” for French, a specific regional dialect of a language such as “en-AU” for English as used in Australia.
 
First, you…

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Try : Handling exceptions with grace in Scala. [Functional way with Scala]


Knoldus

Hey everyone, it’s time to continue our previous blog on how to make our code more robust, concise and better functionally defined at the same time. Here we are moving more towards Scala and leaving traditional Java behind. We will see new types and their usage along with the benefits we get from them.

This blog will show you the best way in my perspective to be used in order to handle the exceptions gracefully in Scala ( The beloved coding language for everyone here at Knoldus ) . Our methods would only be responsible for either returning the results or the exceptions, i.e. we will not write any try-catch blocks to handle the exceptions within different methods.

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Handling HTTPS requests with Akka-HTTPS Server


Knoldus

Hi guys,

In my last blogs I explained how one can create a self-signed certificate and KeyStore in PKCS12. You can go through the previous blog, as we’ll be needing certificate and keystore  for handling HTTPS requests.

  1. https://blog.knoldus.com/2016/10/18/create-a-self-signed-ssl-certificate-using-openssl/
  2. https://blog.knoldus.com/2016/10/26/how-to-create-a-keystore-in-pkcs12-format/

Akka-HTTP provides both Server-Side and Client-Side HTTPS support.

In this blog I’ll be covering the Server-Side HTTPS support.

Let’s start with “why do we need server-side HTTPS support?”

If we want the communication between the browser and the server to be encrypted we need to handle HTTPS request.  HTTPS is often used to protect highly confidential online transactions like online banking and online shopping order forms.

Akka-HTTP supports TLS(Transport Layer Security).

For handling the HTTPS request we need to have the SSL certificate and the KeyStore. Once you have generated both you can go through the example.

In this example, you will see how easily you can handle

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Lambda Architecture with Spark


Knoldus

Hello folks,

Knoldus  organized a knolx session on the topic : Lambda Architecture with Spark.

The presentation covers lambda architecture and implementation with spark.In the presentaion we will discuss components of lambda architecure like batch layer,speed layer and serving layer.We will also discuss it’s advantages and benefits with spark.

You can watch the video of presentation :

Here you can check slide :

Thanks !!


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Finding the Impact of a Tweet using Spark GraphX


Knoldus

Social Network Analysis (SNA), a process of investigating social structures using Networks and Graphs, has become a very hot topic nowadays. Using it, we can answer many questions like:

  • How many connections an individual have ?
  • What is the ability of an individual to influence a network?
  • and so on…

Which can be used for conducting marketing research studies, running ad campaigns, and finding out latest trends. So, it becomes very crucial to identify the impact of an individual or individuals in a social network, so that we can identify key individuals, or Alpha Users (term used in SNA), in a social network.

In this post we are going to see how to find the impact of an individual in a Social Network like Twitter, i.e., How many Twitter Users an individaul can influence via his/her Tweet upto N number of level, i.e., Followers of Followers of Followers… and so on. For, this…

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Knolx: Introduction to KnockoutJs


Knoldus

Hello all,

Knoldus organised a session on Friday, 07 October 2016. In that session, we had an introductory session on Knockout js.

Knockout is a JavaScript library that helps you to create a responsive display(UI). It is based on Model–View–Viewmodel (MVVM) pattern. It provides a simple two-way data binding mechanism between your data model and UI

The slides for the session are as follows:

And, you can also watch the video on youtube link is as follows:


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Functors


Knoldus

While programming in Scala we  often come across a term called Functor. A functor is an extremely simple but powerful concept. In this blog, let us discuss that in more detail.

Theoretically functor is a type of mapping between categories. Given two categories A and B, a functor F maps the objects or entities of A to objects or entities of B. We can simply call it a function of objects or entities.

In programming the functors come into play when we have types or values wrapped inside context or containers. This wrapping up inside context, blocks application of normal functions on the values. This happens because the result on application of function is dependent on the context.

The solution to above scenario is a function that knows how to apply functions to the values wrapped in a context. Internally speaking this function should have a potential to

  • unwrap(fetch) the value…

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Building Analytics Engine Using Akka, Kafka & ElasticSearch


Knoldus

In this blog , I will share my experience on building scalable, distributed and fault-tolerant  Analytics engine using Scala, Akka, Play, Kafka and ElasticSearch.

I would like to take you through the journey of  building an analytics engine which was primarily used for text analysis. The inputs were structured, unstructured and semi-structured data and we were doing a lot of data crunching using it. The Analytics engine was accessible by the rest-client and web-client(Built In with engine)  as shown in below diagram.

architecture-00-b
Here is a quick overview on technology stack :

  1. Play Framework  as Rest Server & Web Application  (Play is MVC  framework based on  lightweight, stateless and web friendly architecture.)
  2. Akka cluster as processing engine.(Akka is a toolkit and runtime for building highly concurrent,distributed, and resilient message driven applications on the JVM.)
  3. ClusterClient (It was contributed module) for communication with Akka cluster. It used to run on rest…

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