Web framework
A web framework (WF) or web application framework (WAF) is a software framework that is designed to support the development of web applications including web services, web resources, and web APIs. Web frameworks provide a standard way to build and deploy web applications. Web frameworks aim to automate the overhead associated with common activities performed in web development. For example, many web frameworks provide libraries for database access, templating frameworks, and session management, and they often promote code reuse.Template:Refn Although they often target development of dynamic web sites, they are also applicable to static websites.Template:Refn
History
Template:Historical information needed As the design of the World Wide Web was not inherently dynamic, early hypertext consisted of hand-coded HTML that was published on web servers. Any modifications to published pages needed to be performed by the pages' author. In 1993, the Common Gateway Interface (CGI) standard was introduced for interfacing external applications with web servers, to provide a dynamic web page that reflected user inputs.<ref>Template:Cite web</ref>
Original implementations of the CGI interface typically had adverse affects on the server load, however, because each request started a separate process.Template:Citation needed More recent implementations utilize persistent processes amongst other techniques to reduce the footprint in the server's resources and offer a general performance boost.
In 1995, full integrated server/language development environments first emerged and new web-specific languages were introduced, such as ColdFusion, PHP, and Active Server Pages.Template:Citation needed
Although the vast majority of languages for creating dynamic web pages have libraries to help with common tasks, web applications often require specific libraries for particular tasks, such as creating HTML (for example, JavaServer Faces).Template:Citation needed
In the late 1990s, mature, "full stack" frameworks began to appear, that often gathered multiple libraries useful for web development into a single cohesive software stack for web developers to use. Examples of this include ASP.NET, Java EE, WebObjects, web2py, OpenACS, Catalyst, Mojolicious, Ruby on Rails, Laravel, Grails, Django, Zend Framework, Yii,<ref>Template:Cite web</ref> CakePHP,<ref>Template:Cite web</ref> and Symfony.Template:Citation needed
Types of framework architectures
Most web frameworks are based on the model–view–controller (MVC) pattern.Template:Citation needed
Model–view–controller (MVC)
Template:Main article Many frameworks follow the MVC architectural pattern to separate the data model with business rules from the user interface. This is generally considered a good practice as it modularizes code, promotes code reuse, and allows multiple interfaces to be applied. In web applications, this permits different views to be presented, such as web pages for humans, and web service interfaces for remote applications.Template:Citation needed
Push-based vs. pull-based
Most MVC frameworks follow a push-based architecture also called "action-based". These frameworks use actions that do the required processing, and then "push" the data to the view layer to render the results.<ref>Template:Cite web</ref> Django, Ruby on Rails, Symfony, Spring MVC, Stripes, CodeIgniter<ref>Template:Cite web</ref> are good examples of this architecture. An alternative to this is pull-based architecture, sometimes also called "component-based". These frameworks start with the view layer, which can then "pull" results from multiple controllers as needed. In this architecture, multiple controllers can be involved with a single view. Lift, Tapestry, JBoss Seam, JavaServer Faces, (µ)Micro, and Wicket are examples of pull-based architectures. Play, Struts, RIFE, and ZK have support for both push- and pull-based application controller calls.Template:Citation needed
Three-tier organization
In three-tier organization, applications are structured around three physical tiers: client, application, and database.<ref>Template:Cite web</ref><ref>Template:Cite web</ref><ref>Template:Cite web</ref><ref>Template:Cite web</ref> The database is normally an RDBMS. The application contains the business logic, running on a server and communicates with the client using HTTP.<ref>Template:Cite web</ref> The client on web applications is a web browser that runs HTML generated by the application layer.<ref>Template:Cite web</ref><ref>Template:Cite web</ref> The term should not be confused with MVC, where, unlike in three-tier architecture, it is considered a good practice to keep business logic away from the controller, the "middle layer".<ref>Template:Cite web</ref><ref>Template:Cite web</ref>
Framework applications
Frameworks are built to support the construction of internet applications based on a single programming language, ranging in focus from general purpose tools such as Zend Framework and Ruby on Rails, which augment the capabilities of a specific language, to native-language programmable packages built around a specific user application, such as Content Management systems, some mobile development tools and some portal tools.Template:Citation needed
General-purpose website frameworks
Web frameworks must function according to the architectural rules of browsers and web protocols such as HTTP, which is stateless. Webpages are served up by a server and can then be modified by the browser using JavaScript. Either approach has its advantages and disadvantages.Template:Citation needed
Server-side page changes typically require that the page be refreshed, but allow any language to be used and more computing power to be utilized. Client-side changes allow the page to be updated in small chunks which feels like a desktop application, but are limited to JavaScript and run in the user's browser, which may have limited computing power. Some mix of the two is typically used.<ref>Template:Cite web</ref> Applications which make heavy use of JavaScript are called single-page applications and typically make use of a client-side JavaScript web framework to organize the code.Template:Citation needed
Server-side
Client-side
Examples include Backbone.js, AngularJS, EmberJS, ReactJS and Vue.js.<ref>Template:Cite web</ref>
Discussion forums, wikis and weblogs
- WikiBase/WikiWikiWebTemplate:Citation needed
Organizational portals
Content management systems (CMS)
Template:Unreferenced section Template:Main article In web application frameworks, content management is the way of organizing, categorizing, and structuring the information resources like text, images, documents, audio and video files so that they can be stored, published, and edited with ease and flexibility.Template:Citation needed
A content management system (CMS) is used to collect, manage, and publish content, storing it either as components or whole documents, while maintaining dynamic links between components.Template:Citation needed
Some projects that have historically been termed content management systems have begun to take on the roles of higher-layer web application frameworks. For instance, Drupal's structure provides a minimal core whose function is extended through modules that provide functions generally associated with web application frameworks. The Joomla platform provides a set of APIs to build web and command-line applications. However, it is debatable whether "management of content" is the primary value of such systems, especially when some, like SilverStripe, provide an object-oriented MVC framework. Add-on modules now enable these systems to function as full-fledged applications beyond the scope of content management. They may provide functional APIs, functional frameworks, coding standards, and many of the functions traditionally associated with Web application frameworks.Template:Citation needed
Features
Template:Unreferenced section Frameworks typically set the control flow of a program and allow the user of the framework to "hook into" that flow by exposing various events.<ref name=":0">Template:Cite web</ref> This "inversion of control" design pattern is considered to be a defining principle of a framework, and benefits the code by enforcing a common flow for a team which everyone can customize in similar ways.<ref name=":0" /> For example, some popular "microframeworks" such as Ruby's Sinatra (which inspired Express.js) allow for "middleware" hooks prior to and after HTTP requests. These middleware functions can be anything, and allow the user to define logging, authentication and session management, and redirecting.<ref>Template:Cite web</ref>
Web template system
Caching
Template:Main article Web caching is the caching of web documents in order to reduce bandwidth usage, server load, and perceived "lag". A web cache stores copies of documents passing through it; subsequent requests may be satisfied from the cache if certain conditions are met. Some application frameworks provide mechanisms for caching documents and bypassing various stages of the page's preparation, such as database access or template interpretation.Template:Citation needed
Security
Template:Main article Some web frameworks come with authentication and authorization frameworks, that enable the web server to identify the users of the application, and restrict access to functions based on some defined criteria. Drupal is one example that provides role-based access to pages, and provides a web-based interface for creating users and assigning them roles.Template:Citation needed
Database access, mapping and configuration
Many web frameworks create a unified API to a database backend, enabling web applications to work with a variety of databases with no code changes, and allowing programmers to work with higher-level concepts. Additionally, some object-oriented frameworks contain mapping tools to provide object-relational mapping, which maps objects to tuples.Template:Citation needed
Some frameworks minimize web application configuration through the use of introspection and/or following well-known conventions. For example, many Java frameworks use Hibernate as a persistence layer, which can generate a database schema at runtime capable of persisting the necessary information. This allows the application designer to design business objects without needing to explicitly define a database schema. Frameworks such as Ruby on Rails can also work in reverse, that is, define properties of model objects at runtime based on a database schema.Template:Citation needed
Other features web frameworks may provide include transactional support and database migration tools.Template:Citation needed
Scaffolding
URL mapping
Template:See also A framework's URL mapping or routing facility is the mechanism by which the framework interprets URLs. Some frameworks, such as Drupal and Django, match the provided URL against pre-determined patterns using regular expressions, while some others use rewriting techniques to translate the provided URL into one that the underlying engine will recognize. Another technique is that of graph traversal such as used by Zope, where a URL is decomposed in steps that traverse an object graph (of models and views).Template:Citation needed
A URL mapping system that uses pattern matching or rewriting to route and handle requests allows for shorter more "friendly URLs" to be used, increasing the simplicity of the site and allowing for better indexing by search engines. For example, a URL that ends with "/page.cgi?cat=science&topic=physics" could be changed to simply "/page/science/physics". This makes the URL easier for people to remember, read and write, and provides search engines with better information about the structural layout of the site. A graph traversal approach also tends to result in the creation of friendly URLs. A shorter URL such as "/page/science" tends to exist by default as that is simply a shorter form of the longer traversal to "/page/science/physics".Template:Citation needed
Ajax
Template:Main article Ajax, shorthand for "Asynchronous JavaScript and XML", is a web development technique for creating web applications. The intent is to make web pages feel more responsive by exchanging small amounts of data with the server behind the scenes, so that the entire web page does not have to be reloaded each time the user requests a change. This is intended to increase a web page's interactivity, speed, and usability.Template:Citation needed
Due to the complexity of Ajax programming in JavaScript, there are numerous Ajax frameworks that exclusively deal with Ajax support. Some Ajax frameworks are even embedded as a part of larger frameworks. For example, the jQuery JavaScript library is included in Ruby on Rails.Template:Citation needed
With the increased interest in developing "Web 2.0" rich media applications, the complexity of programming directly in Ajax and JavaScript has become so apparent that compiler technology has stepped in, to allow developers to code in high-level languages such as Java, Python and Ruby. The first of these compilers was Morfik followed by Google Web Toolkit, with ports to Python and Ruby in the form of Pyjs and RubyJS following some time after. These compilers and their associated widget set libraries make the development of rich media Ajax applications much more akin to that of developing desktop applications.Template:Citation needed
Web services
Template:Main article Some frameworks provide tools for creating and providing web services. These utilities may offer similar tools as the rest of the web application.Template:Citation needed
Web resources
Template:Main article A number of newer Web 2.0 RESTful frameworks are now providing resource-oriented architecture (ROA) infrastructure for building collections of resources in a sort of Semantic Web ontology, based on concepts from Resource Description Framework (RDF).Template:Citation needed ..........
See also
- Comparison of web frameworks
- Rich Internet application
- List of rich Internet application frameworks
- List of web service frameworks
- Application server
- Comparison of application servers
- Application framework
- Application security
- Convention over configuration
- Don't repeat yourself (DRY)
- Solution stack
- Multiple phone web-based application framework
References
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