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 tend to be used 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 forms 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 disadvantages for three points of view: software owner, software contractor (developer) and person. There can be other styles but they basically drop to these three as their subtypes.
First we'll define a web application: it is a client-server application - there is a browser (the client) and a web server. The logic of a web application is distributed on the list of server and the client, there is a channel for information exchange, and the data is stored mainly on the server. Further details depend on the architecture: different ones distribute the logic in different ways. It can be placed on the server in addition to on the client side.
It's near to impossible to evaluate these completely 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 used.
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. Capability to increase computation power or disc space under increases in amounts of information and/or number of users. In case the allocated scalable system is used, one must provide data consistence, availability and partition tolerance (CAP theorem). It is 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 on the framework and implementation rather than the type of web architecture.
Testability. Possibility and easiness of automated unit testing.
Software owner:
Functional extendability. https://archicadteam.com/ within minimal time and budget.
SEO. Users must be able to find the application through any search engine.
Support. Expenses on app infrastructure - hardware, network infrastructure, maintenance staff.
Security. The software owner must be sure both business data and information about users are kept secure. As the main security criterion we'll consider 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 all these architectures are equally exposed to break-ins - this channel can be the same.
Conversion: site - mobile or desktop application. Possibility to publish the application on mobile markets or even 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 showing what's good and what's bad. It's more of a detailed review that presents the possible options of choice.
Let's outline three main types of web applications based on the roles performed by the server and your client browser.
Type 1: Server-side HTML
Probably the most widespread architecture. The server generates HTML-content and sends it to the client as a full-fledged HTML-page. Sometimes this architecture is called ''Web 1.0'', because it was the first to appear and currently dominates the net.
Responsiveness/Usability: 1/5. Minimal optimal value among these architectures. It's so since there is a great amount of data transferred between the server and the client. An individual has to wait until the whole page reloads, giving an answer to trivial actions, for instance, when only a part of the page should be reloaded. UI templates on the client depend on the frameworks applied on the server. Because of the limitations of mobile internet and large sums of transferred data, this architecture is hardly applicable in the mobile segment. You can find 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 your 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 due to the fact that by default one URL receives particular HTML-content on the server.
SEO: 5/5. Rather easily implemented, similarly to the previous criterion - the content is known beforehand.
Speed of development: 5/5. This is the oldest architecture, so it is possible to choose any server language and framework for particular needs.
Scalability: 4/5. If we take a look at the generation of HTML, under 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 task may be 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 just because a big amount of data must be transferred, containing HTML, design, and business data. Therefore it's necessary to generate data for the whole page (not only for the changed business data), and all the accompanying information (such as design).
Testability: 4/5. The positive thing is that there's no need in special tools, which support JavaScript interpretation, to test the front-end, and this 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 may 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. In many instances it's simply impossible. Rarely there's an exception (more of exotics): for example, 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 in node-webkit or analogous means.