3 Types Of Web Application Architecture

Such terms as web app, front-end architecture, Web 2.0, and HTML5 apps have recently become trendy. Unfortunately these terms are often found in a misleading context which doesn't consider the full specificity of implementation and using web app architecture. Today we'll look for out more about the types of web application architecture in the light of the most recent web trends and key issues that matter to software owners.

We'll outline 3 main forms of web architecture and discuss their advantages and drawbacks for three points of view: software owner, software contractor (developer) and end user. There can be other styles but they basically come down to these three as their subtypes.

First we'll define a web application: it's a client-server application - there is a browser (the client) and a web server. The logic of a web application is distributed among the server and the client, there's a channel for information exchange, and the info is stored mainly on the server. Further details be determined by the architecture: different styles distribute the logic in different ways. It can be positioned on the server as well as on the client side.

It's near to impossible to judge these very different architectures impartially. But we'll try to, using several criteria of evaluation:

User:

Responsiveness/Usability. Updates of data on pages, switching between pages (response time). Such qualities of interface as richness and intuitiveness in use.

Linkability. Capability to save bookmarks and links to various parts of the website.

Offline work. Speaks for itself.

Developer:

Speed of development. Addition of new functional features, refactoring, parallelizing the development process between developers, layout designers, etc.

Performance. Maximum speed of response from the server with minimum consumption of computation power.

Scalability. Ability to increase computation power or disc space under increases in amounts of information and/or number of users. In case the allocated scalable system can be used, one must definitely provide data consistence, availability and partition tolerance (CAP theorem). It is also worth noting that the case, when the number of features/screens of the client app is increased at the program owner's request, depends on the framework and implementation rather than the type of web architecture.

Testability. Possibility and easiness of automated unit testing.

Software owner:

Functional extendability. Adding functionality within minimal time and budget.

SEO. Users must be able to discover the application through any internet search engine.

Support. Expenses on app infrastructure - hardware, network infrastructure, maintenance staff.

Security. The software owner should be sure that both business data and information about users are kept secure. As the main security criterion we'll think about the possibility of changes in functionality of app behavior on the client side, and all associated risks. Standard dangers will be the same for the compared architectures. We do not consider security on the 'server-client' channel, because all these architectures are equally subjected to break-ins - this channel could possibly be the same.

Conversion: site - mobile or desktop application. Possibility to create the application form on mobile markets or to make a desktop application from it with minimal additional costs.

Some of these criteria may seem inaccurate, but the purpose of the article is not showing what's good and what's bad. It's more of a detailed review that presents the possible options of preference.

Let's outline three main forms of web applications according to the roles performed by the server and your client browser.

Type 1: Server-side HTML

The most widespread architecture. The server generates HTML-content and sends it to your client as a full-fledged HTML-page. Sometimes this architecture is named Web 1.0, because it was the first ever to appear and currently dominates the web.

Responsiveness/Usability: 1/5. The least optimal value among these architectures. It's so since there is a great amount of data transferred between your server and the client. The user has to wait before whole page reloads, giving an answer to trivial actions, for example, when only a area of the page should be reloaded. UI templates on the client depend on the frameworks applied on the server. Due to the limitations of mobile internet and huge amounts of transferred data, this architecture is hardly applicable in the mobile segment. There are no method of sending instant data updates or changes in real time. If we consider the chance for real-time updates via generation of ready chunks of content on the server side and updates of the client (through AJAX, WebSockets), plus design with partial changes of a page, we'll exceed this architecture.

Linkability: 5/5. The best of the three, since it is the easiest implementable. It's because of the fact that by default one URL receives particular HTML-content on the server.

SEO: 5/5. Rather easily implemented, much like the previous criterion - the content is known beforehand.

Speed of development: 5/5. This is actually the oldest architecture, so it is possible to choose any server language and framework for particular needs.

Scalability: 4/5. If we check out the generation of HTML, beneath the increasing load comes the moment when load balance will undoubtedly be needed. There's a a lot more complicated situation with scaling databases, but this is the same for these three architectures.

Performance: 3/5. Tightly bound to responsiveness and scalability with regard to traffic, speed etc. Performance is relatively low because a big amount of data must be transferred, containing HTML, design, and business data. Therefore it's essential to generate data for the whole page (not merely for the changed business data), and all the accompanying information (such as design).

Testability: 4/5. The positive thing is that there surely is no need in special tools, which support JavaScript interpretation, to check the front-end, and the content is static.

Security: 4/5. The application behavior logic is on the server side. However, reformas en valencia are transferred overtly, so a protected channel could be needed (which is basically a story of any architecture that concerns the server). All of the security functionality is on the server side.

Conversion: site - mobile or desktop application: 0/5. Usually it's simply impossible. Rarely there's an exception (more of exotics): for instance, if the server is realized upon node.js, and you can find no large databases; or if one utilizes third-party web services for data acquisition (however, it is a more sophisticated variant of architecture). Thus one can wrap the application form in node-webkit or analogous means.