Body Girdles

Such terms as ”web app”, ”front-end architecture”, ”Web 2.0”, and ”HTML5 apps” have recently become trendy. Unfortunately these terms tend to be found in a misleading context which doesn’t consider the full specificity of implementation and using web app architecture. Today we’ll try to find out more about the types of web application architecture in the light of the latest web trends and key conditions that matter to software owners.

We’ll outline 3 main types 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 drop 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 ones distribute the logic in different ways. It can be positioned on the server in addition to on the client side.

It’s near to impossible to judge these very different architectures impartially. But we’ll make an effort 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. Ability to save bookmarks and links to various sections 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 levels of information and/or number of users. In case the allocated scalable system is used, one must definitely provide data consistence, availability and partition tolerance (CAP theorem). It’s also worth noting that the case, once the number of features/screens of your client app is increased at the software owner’s request, depends upon the framework and implementation as opposed to 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 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 regarding users are kept secure. As the main security criterion we’ll think about the chance for changes in functionality of app behavior on your client side, and all associated risks. Standard dangers are the same for the compared architectures. We do not consider security on the ‘server-client’ channel, because each one of these architectures are equally subjected to break-ins – this channel can be the same.
Conversion: site – mobile or desktop application. Possibility to publish the application form on mobile markets or to make a desktop application out of it with minimal additional costs.

Some of these criteria might seem inaccurate, but the purpose of the article is not to show what’s good and what’s bad. It’s more of a detailed review that shows the possible options of preference.

Let’s outline three main types of web applications based on the roles performed by the server and the 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”, since it was the first to appear and currently dominates the net.

Responsiveness/Usability: 1/5. The least optimal value among these architectures. It’s so because there is plenty of data transferred between the server and the client. The user has to wait until the whole page reloads, giving an answer to trivial actions, for example, when only a area of the page needs to be reloaded. UI templates on your client depend directly on the frameworks applied on the server. As a result of limitations of mobile internet and large sums of transferred data, this architecture is hardly applicable in the mobile segment. You can find no means 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 full page, we’ll exceed this architecture.

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

SEO: 5/5. Rather easily implemented, much like the previous criterion – this content is known beforehand.
Speed of development: 5/5. This is the oldest architecture, so it is possible to select any server language and framework for particular needs.

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

Performance: 3/5. Tightly bound to responsiveness and scalability when it comes to traffic, speed etc. Performance is relatively low because a big amount of data should be transferred, containing HTML, design, and business data. Therefore arquitectura valencia to generate data for your 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 form behavior logic is on the server side. However, data are transferred overtly, so a protected channel could be needed (that is basically a story of any architecture that concerns the server). All the security functionality is on the server side.

Conversion: site – mobile or desktop application: 0/5. In most cases 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 you can wrap the application form in node-webkit or analogous means.