|Developer(s)||The Seaside Team|
|Stable release||3.0 / September 13, 2010|
|Preview release||3.0-alpha5 / September 8, 2009|
|Type||Web application framework|
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. Seaside is a continuation-based web application framework based on the ability to manipulate the execution stack of some implementations of Smalltalk.
A distinctive feature of Seaside is its integrated development environment, providing access to development tools and debugging support within an application. In development-mode, unhandled errors are reported to the web page; developers can access and alter the program code and state directly from the web page, allowing bug identification and fixing process to occur within an integrated development environment.
A Seaside application is a collection of interacting components. Each component stores state across page views and can "render" itself to the HTML stream. Thus, it is straightforward to write a component once and then reuse it elsewhere in an application. Seaside also supports the notion of tasks, which allow the programmer to describe the high-level logic of component interaction.
Seaside is not template-oriented, and does not offer the generation or use of HTML templates; HTML markup is generated programmatically. (The Seaside-based Pier content-management framework does offer wiki-markup syntax for templating.) 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 separation of structure (markup) from content and presentation (CSS). Seaside's combination of components, callbacks, and closures can significantly reduce the semantic gap between a complex workflow and its representation in code.
Over the last few years, some best practices have come to be widely accepted in the web development field:
- 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; Avi Bryant describes it as a 'heretical' framework. He argues 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.
Although the main development of Seaside is implemented in Pharo, there exist ports for other Smalltalk dialects. Michel Bany implemented ports to VisualWorks through Seaside version 2.7; Cincom supports Seaside as part of VisualWorks as of early 2008. Instantiations announced Seaside support in its VA Smalltalk version 8.0. As of February 2009 VA Smalltalk 8.0 is in beta. Esteban Maringolo maintained the 2.8 port, plus some other add-ons (such as script.aculo.us) for Dolphin Smalltalk X6. Gemstone Systems implemented a port to Gemstone/S. A port of 2.8 was completed for GemStone, and a preliminary version of 3.0 runs on GNU Smalltalk 3.0a and later.
- Compared to other web development frameworks, Seaside is memory intensive. A single session could accumulate several hundred kilobytes of RAM. A later release of Seaside (2.8) significantly reduces this footprint (e.g. a formerly typical 200 KB footprint becomes 50 KB) Interesting discussion in http://forum.world.st/Seaside-memory-consumption-td97508.html.
- Seaside does not follow Representational State Transfer (REST) by default. Instead Uniform Resource Locators (URLs) hold session key information, and meaningful URLs must be generated explicitly.
Open-source projects using it
- 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
Proprietary projects using it
- Dabble DB - web-based database application
- Cmsbox - a Seaside-powered CMS which has been made available by netstyle.ch for the Swiss marketplace.
- GLASS (software bundle)
- Nagare (web framework)
- List of web application frameworks
- Content management framework
- Comparison of web application frameworks
- Seaside — a Multiple Control Flow Web Application Framework
- IBM DeveloperWorks: Crossing borders: Continuations, Web development, and Java programming
- Seaside: A Flexible Environment for Building Dynamic Web Applications
- Debugging Seaside Applications
- Avi Bryant explains why Seaside doesn't use templates
- Web Application Frameworks: A Comparative Study
- Screencast: Seaside Comet Chat Application
- 'Web Heresies: The Seaside Framework' Session notes, OSCON 2006
- "Seaside 2.9 is current implemented on Pharo that serves as a reference implementation."
- Seaside for Dolphin Smalltalk blog
- Does Seaside run on GNU Smalltalk, GNU Smalltalk FAQ
- Jon Udell article in InfoWorld
- Seaside homepage.
- Dynamic Web Development with Seaside is an open book on the Seaside Web Framework.
- The Seaside Tutorial describes step by step the development of a Seaside application.
- 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.