React vs. Angular components

As an IT consultant I have the opportunity to experiment with different libraries and frameworks. Every time I should solve a particular (architectural) problem, I start thinking what kind of tools I know and how they could help me in that particular situation. I have had great experience both with Angular and React for building dynamic front-end application. In this series of posts I want to do a simple comparison between them in terms of how they help developers define and use components. Please note that I am not going to draw a conclusion about which of them is better. I really do think that both have their strong sides, so it is a matter of approach (and preference sometimes) which one you would use. Continue Reading…

HttpWebRequest keeps timing out

It has already happened to me a couple of times and every time I forget what the issue was and how to solve it. That’s why I decided to write a short post about it, so hopefully next time I will remember. :-) The problem arises when making a few (independent) HTTP requests using C#’s HttpWebRequest. At first it sounds like a very usual thing to do, but the mystical part of it is that the first few requests succeed and then at a certain point the others start timing out. You may be tempted to increase the Timeout first, but you will soon understand that it does not solve the problem. Continue Reading…

Angular 2 gets rid of controllers

In my previous post I talked about the problems of controllers (both at the back-end and the front-end). The issue is that controllers are too general and tend to become full with mixed logic, especially if the page they control has many UI pieces. So instead of having one controller per page, we can have one controller per component and hence decrease the coupling in one’s code.

Some JavaScript libraries, f.x. React, are designed with the component in the center. In Angular 1.x we have the concepts of a controller and a directive. One can attach a controller to any part of the page or when using a router, a controller is automatically assigned to the view. You can easily remove all usages of controllers on your page simply by moving the code into an appropriate directive. Do not forget that you can also rely on the different types of services in Angular for custom logic.

In Angular 2 the notion of controller is completely removed. You should work with directives only and you can actually choose what kind of a directive you want to use for the specific case:

  • Component directives provide a “static” template with some logic behind. It is the same as a directive with a template and an isolated scope in Angular 1.x
  • Template directives work with a user-defined template. It is similar to a directive with transclude in Angular 1.x
  • Decorator directives add extra functionality to an existing DOM element (see Decorator pattern). It is the same as a directive with no translude, no own scope and no template in Angular 1.x

If you think you will miss the mapping to a controller from the router in Angular 2, you can actually do a mapping to a ComponentDirective instead, but I would still opt for slicing your views into smaller components.

From MVC towards components

The nature of HTTP is to provide resources where each resource is identified by a unique URL. A resource can be any kind of file: image, text file, font. Initially web sites used to deliver static HTML pages, which were pretty much limited in terms of content. CGI and server-side scripting languages like PHP, ASP(.NET), and JSP changed this by generating dynamic HTML on the server and sending it back to the client. This allowed the page content to be “configured” by the browser, f.x. using query string. This traditional web architecture is denoted on the diagram below.

Traditional web architecture

It all worked fine until the Web became more complex and developers started to put more and more logic on the server. We ended up having to make requests like /index.php?module=employees&id=5 (especially with some CMS systems). This architecture tended eventually to cause many problems, from search-engine optimization to code maintenance. Continue Reading…