Few weeks ago when I was working on my pet project, I wanted to make it an SBT plugin. Since I had to spend some time studying SBT docs, I decided to write a short tutorial explaining how to write and deploy a SBT plugin.
Scala-ts: Scala to TypeScript code generator
I have started using TypeScript a few weeks ago at work. It turns out to be a great language which lets you avoid many problems caused by JavaScript’s dynamic typing, facilitates code readibility and code refactoring and does that at relatively small cost thanks to modern, concise syntax.
Issues with asynchronous IO in web applications
Building servers with non-blocking IO has been quite popular these days. Tests have shown that it does actually improve scalability of web applications. However, my experience show that it comes at a cost. In this post I am going to discuss some negative aspects of writing asynchronous code based on Scala’s Futures.
Using Automapper to improve performance of Entity Framework
Entity Framework is an ORM technology widely used in the .NET world. It’s very convenient to use and lets you forget about SQL… well, at least until you hit performance issues.
Looking at the web applications I worked on, database access usually turned out to be the first thing to improve when optimizing application performance.
Asynchronous programming in Scala vs C#
In one of my recent post I compared two different approaches that authors of Scala and C# chose to solve the same problem. This post is based on the same idea but the problem being solved is asynchronous programming.
Conclusions after first four months of blogging
In this short post I name some random conclusions I had after the first four months of blogging. I hope this will be helpful for people who are considering starting their own programming blog (which I fully recommend to do!).
Scala’s Option monad versus null-conditional operator in C#
Today I will talk about an awesome feature of C# 6.0. We will see how it can help us understand monads in Scala!
Null-conditional operator
Imagine we have a nested data model and want to call some method on a property nested deeply inside an object graph. Let’s assume that Article does not have to have an Author, the Author does not have to have an Address and the address does not have to have a City (for example this data can be missing from our database).
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public class Address { public string Street { get; set; } public string City { get; set; } // can be null } public class Author { public string Name { get; set; } public string Email { get; set; } public Address Address { get; set; } // can be null } public class Article { public string Title { get; set; } public string Content { get; set; } public Author Author { get; set;} // can be null } Console.WriteLine(article.Author.Address.City.ToUpper()); |
This is very unsafe code since we are at risk of NullReferenceException. We have to introduce some null checks in order to avoid the exception.
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if (article != null) { if (article.Author != null) { if (article.Author.Address != null) { if (article.Author.Address.City != null) { Console.WriteLine(article.Author.Address.City.ToUpper()); } } } } |
Yuck! So much boilerplater code to do a very simple thing. It’s really unreadable and confusing.
Accessing request parameters from inside a Future in Scalatra
Scalatra is an awesome, lightweight web framework for Scala. It’s perfect for building REST APIs. One of its less known features is support for asynchronous programming using Scala’s Futures.
Combining two objects in lodash
I’m a huge fan of the lodash library. It encourages functional programming style in JavaScript and as a result lets you write less error-prone and more readable code.
Some time ago I discovered the assign (extend) function which copies properties from target object(s) and assigns them to the target object. It also returns the target object. This is very handy whenever you want to combine properties from two objects into one object.
Scala for C# developers – part III
I’m back from a rather lenghty break and would like to continue the Scala for C# developers series. So far I have covered the syntax, the basics of OO in Scala and functions. In this post I will look at the Option type and pattern matching.