ajax continuation continuations development framework idea pl>smalltalk research seaside smalltalk software squeak step swdev web web_application_framework webapplication webframework

My tags:

From Wikipedia, the free encyclopedia

Seaside

Screenshot  Screenshot of a web application in development mode
Developed by	The Seaside Team
Latest release	2.8.3 / 2008-8-24; 267 days ago
Preview release	2.9-alpha1 / 2008-11-9; 190 days ago
Written in	Smalltalk
Operating system	Cross-platform
Type	Web application framework
License	MIT License
Website	http://www.seaside.st/

Seaside is a free and open source web application framework for developing web applications in Smalltalk.

Seaside provides a component architecture in which web pages are built as trees of individual, stateful components, each encapsulating a small portion of a page. Seaside uses continuations to model multiple independent flows between different components.^[1] Seaside is a continuation-based web application framework^[2] based on the ability to manipulate the execution stack of some implementations of Smalltalk.

Contents 1 Key features 2 Philosophy of Seaside 3 Ports 4 Criticisms 5 Open-source Projects using Seaside 6 Commercial Projects using Seaside 7 See also 8 References 9 External links

[edit] Key features

It is Seaside's implementation of continuations that makes it of particular interest; continuations provide a mechanism for rollback and resumption. This is essential in a web browser environment where "refresh" and "back" buttons may interrupt the flow of processing,^[3] and continuation servers give the developer the ability to maintain state on the server in a scalable manner^[4].

Another distinctive feature of Seaside is that it comes with an integrated development environment, providing access to development tools and debugging support from within the applications. In development mode, unhandled errors are reported to the web page, and developers can access and alter the program code and state directly from the web page, allowing the bug identification and fixing process to happen in an integrated environment.^[5]

A Seaside application is a collection of interacting components. Each component stores state across page views and can "render" itself to the HTML stream. Because of this setup, it is straightforward to write a component once and then reuse it elsewhere. Seaside also supports the notion of tasks, which allow the programmer to describe the high-level logic of how components interact.

Seaside does not come with any built-in tools to support the generation or use of HTML templates; HTML markup is generated programmatically. (The Seaside-based Pier content-management framework adds wiki-markup syntax as a templating solution, however.) Seaside uses callbacks on closures to specify actions to be taken when clicking on a link or submitting a form. The developers and users of Seaside argue that this helps enforce the good discipline of separating structure (markup) from content and presentation (CSS)^[6]. Seaside's combination of components, callbacks, and closures can significantly reduce the semantic gap between a complex workflow and its representation in code^[7].

Seaside supports Ajax through the officially supported script.aculo.us and JQuery integration. It also supports Comet style server-push technology^[8].

[edit] Philosophy of Seaside

Over the last few years, some best practices have come to be widely accepted in the web development world:

• Share as little state as possible.

• Use clean, carefully chosen, and meaningful URLs.
• Use templates to separate the model from the presentation.

Seaside deliberately breaks all of these rules, indeed Avi Bryant describes it as a 'heretical' framework. He argues^[9] that this careful and reasoned rejection of the conventional wisdoms of web development has led to a very effective model for the development of web applications.

[edit] Ports

Although the main development of Seaside happens in Squeak there exist ports for other Smalltalk dialects. Michel Bany did regular ports to VisualWorks through Seaside version 2.7; Cincom is supporting Seaside as part of VisualWorks as of early 2008. Instantiations has announced Seaside support in its VA Smalltalk version 8.0. As of February 2009 VA Smalltalk 8.0 is in beta. Esteban Maringolo maintains the 2.8 port, plus some other add-ons (such as script.aculo.us) for Dolphin Smalltalk X6.^[10]. Gemstone Systems is working on a port to Gemstone/S ^[11]. A port of 2.8 has been completed on GemStone^[12], and preliminary version of 2.9 runs on GNU Smalltalk 3.0a and later^[13].

[edit] Criticisms

• Compared to other web development frameworks, Seaside is memory intensive. A single session could accumulate several hundred kilobytes of RAM. The latest release of Seaside (2.8) significantly reduces this footprint (e.g. a formerly typical 200kb becomes 50kb).
• Seaside does not follow REST by default. Instead URLs hold session key information, and meaningful URLs have to be generated explicitly.
• Documentation is sparse, scattered and often outdated. It has to be collected from blog posts, tutorials and mailing list posts.

[edit] Open-source Projects using Seaside

• Magritte - a meta-description framework with a tight integration into Seaside
• Pier - a content management system and high level application framework for Seaside
• ADK Project

[edit] Commercial Projects using Seaside

• Dabble DB - web-based database application ^[14]
• Cmsbox - a Seaside-powered CMS which has been made available by netstyle.ch for the Swiss marketplace.
• Auctomatic - a web application to manage your inventory and ebay sales

[edit] See also

• List of web application frameworks
• Content management framework
• Comparison of web application frameworks

[edit] References

v • d • e Web Application Frameworks Apache  · Eclipse OSI  · SourceForge ASP.NET ASP.NET MVC · BFC · DotNetNuke · MonoRail · Umbraco ColdFusion ColdSpring · Fusebox · Mach-II · Model-Glue · onTap · on Wheels Common Lisp ABCL-web · blow · BKNR · SymbolicWeb · UnCommon Web Java Apache Struts · AppFuse · Flexive · GWT · Guice · Grails · IT Mill Toolkit · ItsNat · JavaServer Faces · Makumba · OpenXava · Reasonable Server Faces · RIFE · Restlet · Seams · Spring · Stripes · Tapestry · Trails · WebWork · Wicket Perl Catalyst · Interchange · Mason PHP Agavi · Akelos · CakePHP · Chisimba · CodeIgniter · Drupal · Horde · Kohana · Kolibri · KumbiaPHP · Midgard · Orinoco Framework · PEAR · PHPNuke · PHPonTrax · Seagull · Simplicity · Symfony · WASP · Yii Framework · Zend · Zoop Python Django · TurboGears · Pyjamas · Pylons · web2py Ruby Ruby on Rails  · Merb  · Sinatra Scala Lift Smalltalk AIDA/Web · Seaside Runtimes Silverlight · AIR · FLV · JavaFX · JRE / JVM · Virtual Machines (Platforms  · Applications) more... Other languages Application Express (PL/SQL) · Fusebox (ColdFusion and PHP) · OpenACS (Tcl) · Yaws (Erlang) · HAppS (Haskell) · SproutCore (JavaScript/Ruby) See Also Facelets · Interface · Widget · Ajax · API · RIA · CMS · IDE · DBMS

[edit] External links

• Seaside homepage.
• Seaside for Squeak Smalltalk.
• Terse Guide to Seaside.
• Video of Lukas Renggli's talk The Heretic Web Framework from the Studencki Festiwal Informatyczny in Cracow, March 2007, with PDF slides
• Seaside for Cincom VisualWorks Smalltalk.
• Comparison of Seaside and Rails.
• Borges - Ruby port of Seaside 2.0.