Merb is a discontinued

model–view–controller Model–view–controller (MVC) is a software architectural pattern commonly used for developing user interfaces that divide the related program logic into three interconnected elements. This is done to separate internal representations of infor ...

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 ...

Ruby A ruby is a pinkish red to blood-red colored gemstone, a variety of the mineral corundum ( aluminium oxide). Ruby is one of the most popular traditional jewelry gems and is very durable. Other varieties of gem-quality corundum are called sa ...

, notable as a precursor to Rails 3. It brought increased focus on speed and modularity to Rails 3. The name Merb is a contraction of "

Mongrel A mongrel, mutt or mixed-breed dog is a dog that does not belong to one officially recognized Dog breed, breed and including those that are the result of intentional Dog breeding, breeding. Although the term ''mixed-breed dog'' is sometime ...

" and "

Erb Erb, ERB or ErB may refer to: People * Edgar Rice Burroughs (1875–1950), American author * Erb of Gwent (–), king of Gwent and Glywysing Surname * Abraham Erb (1772–1830), American-born Canadian settler * Albrecht Erb (1628–1714), Austr ...

Precursor to and merge with Rails 3

Merb began as a "clean-room" implementation of the

Rails Rail or rails may refer to: Rail transport *Rail transport and related matters *Rail (rail transport) or railway lines, the running surface of a railway Arts and media Film * ''Rails'' (film), a 1929 Italian film by Mario Camerini * ''Rail'' ( ...

controller stack but grew to incorporate several ideas that deviated from Rails's spirit and methodology at the time, most notably component modularity, extensible

API An application programming interface (API) is a way for two or more computer programs to communicate with each other. It is a type of software Interface (computing), interface, offering a service to other pieces of software. A document or standa ...

design, and vertical scalability. It was developed by Ezra Zygmuntowicz and Yehuda Katz. Most of these capabilities were added to Rails during the Rails 3/Merb merger. Merb was first released at the 2008 RubyConf and development has since stopped; Rails 3 ,therefore, serves as both the successor to Rails 2 and the successor to Merb.

Differences from Ruby on Rails

Merb's design attempted to address several criticisms of

2: * lack of component modularity (

monolithic A monolith is a monument or natural feature consisting of a single massive stone or rock. Monolith or monolithic may also refer to: Architecture * Monolithic architecture, a style of construction in which a building is carved, cast or excavated ...

design) * lack of an extensible API * lack of vertical scalability

Modularity

Merb itself encompassed only the controller layer in

MVC MVC may refer to: Science and technology * Maximum-value composite procedure, an imaging procedure * Multivariable calculus, a concept in mathematics * Multivariable control, a concept in process engineering * Mechanical vapor compression, a desal ...

architecture, and used a suite of complementary, optional plugins together to assemble applications. The primary integration points were the web server interface, the model layer, the view layer, and controller extensions and add-ons. Merb's default application stack incorporated

Datamapper In software engineering, the data mapper pattern is an architectural pattern. It was named by Martin Fowler in his 2003 book ''Patterns of Enterprise Application Architecture''. The interface of an object conforming to this pattern would include f ...

for models, ERB for views, and

Rack Rack or racks may refer to: Storage and installation * Amp rack, short for amplifier rack, a piece of furniture in which amplifiers are mounted * Bicycle rack, a frame for storing bicycles when not in use * Bustle rack, a type of storage bin ...

and Mongrel as the web server layer.

Well-defined API

Before the Merb / Rails 3 merge, Rails lacked a well-defined, documented, public API for extensions and plug-ins, leading to issues when Rails changes broke monkey-patches performed by plug-ins. With the Rails 3 / Merb merge, Rails gained a defined public API with a test suite, giving users and plugin developers a clearer, more stable API to build against, reducing plugin breakage from release to release.

Performance and scalability

Some early versions of Rails received bad publicity for lack of performance, frequently due to developer confusion about ActiveRecord queries.

David Heinemeier Hansson David Heinemeier Hansson is a Denmark, Danish programmer, and the creator of the popular Ruby on Rails web development Software framework, framework and the Instiki, Instiki wiki. He is also a partner at the web-based software development firm B ...

, the creator of Rails, stated that Merb re-wrote many core Rails pieces to be faster, and incorporated those changes from Merb in the Rails 3 merge, promising users that "Rails 3 will get all the performance attention that the Merb guys are known for".

References

External links

Merbivore - Official Merb Site
{{Application frameworks Free computer libraries Free software programmed in Ruby Web frameworks Software using the MIT license