Is there a bare-bones Scala web framework? I basically need the essential features such as:
Routing.
GET/POST/PUT parameter handling.
A simple templating engine (content substitution based).
Serialization (JSON, YAML)
I don't like Lift as it does too much for me, as I would like complete control over the generated HTML, meaning that I want to be able to write 100% of the HTML/CSS/JS code.
Is there such a framework? Or is it possible to use Lift in a way that no HTML is generated behind the scenes? Or would I be better of writing a normal servlet?
Perhaps you'd like something like Scalatra or Unfiltered? On a separate note, you need not give up any control of your HTML/CSS/JS in a Lift app if you don't want to.
You can just use Lift to generate services, such as REST ones, is that more or less what you are looking for? http://www.assembla.com/spaces/liftweb/wiki/REST_Web_Services
If we take a look at What Scala web-frameworks are available? none of them have a great simple templating engine, at least to me it seems that way. SweetScala seems the closest though http://code.google.com/p/sweetscala/wiki/GettingStarted
Peter gave a great answer... I'll expand on it a little.
Lift gives you a ton of control and access to raw HTTP requests as well as providing a ton of abstractions on top of the HTTP level. It's your choice on how much or how little you want Lift to do.
You can built a REST-based application using Lift's RestHelper. See http://simply.liftweb.net/index-Chapter-5.html The advantage that Lift's RestHelper gives you over most MVC/Routing based approaches is type-safety and access control at the very edge of your application. But using Scala's pattern matching extractors, you can insure that parameters delivered to the business logic of your application have already been materialized and checked for access control. Further, Lift's REST support will be as concise or more concise than other web frameworks.
In terms of Lift's HTML handling, you have a ton of control over the creation of the HTML, as long as you want to generate HTML as a valid DOM rather than as a series of Strings.
Most web frameworks force you to emit Strings when you're composing HTML. It's up to the developer to properly HTML-escape Strings. It's up to the developer to make sure that closing tags line up correctly. With Lift, you get this kind of thing for free.
You can serve HTML from Lift apps in MVC style. See https://github.com/dpp/hoisted (this is the code that powers http://liftweb.net)
In the "standard" configuration of Lift apps, Lift does some post-processing of the HTML if, and only if, you use certain construct. So, if you put a <head> tag in the body, the HTML page, Lift will take the contents of that <head> tag and move it to the head section of the page. If you include calls to Lift's Comet support, Lift will insert JavaScript on the page to do long polling. But these features are optional and they only happen if you use certain features in Lift.
I hope this helps you understand the benefits of using Lift.
Two more frameworks for you to consider:
Play is a simple REST framework that is gaining in popularity, and has a nice Scala interface. Its templates translate relatively simply into Scala functions. As of a couple months ago there were difficulties with using JSON packages (like lift-json) that unpack data into case classes because Play has a custom classloader for rapid development. Not sure if this issue is resolved. The Scala company Typesafe uses Play for their site. Play integrates with Akka, and one of the Akka lead developers, Viktor Klang, recommended Play a while back.
A little further off the beaten track, there is Spray. I can't speak to the details, but the Wiki looks intriguing. To my eyes, Spray looks to be elegantly designed around Akka integration. I don't think it comes with a templating engine, but it would probably be possible to interface with Scalate (see the mailing list discussion).
Not a Scala framework per-se, but I've had good luck with Jetty+JAX-RS+Scala+Freemarker. These are all pretty heavily battle-tested technologies, and there's no problems with Scala integration. A small shim is necessary to adapt Freemarker to understand Scala collections and properties, but nothing challenging.
Scalatra is pretty bare bones with the scala goodness. Easy to configure, easy to handle Bare HTTP stuff. It is similar to sinatra of scala.
Scalatra also has good Maven support and coexists well with traditional java servlets.
The modern Scala web framework are: Play (on Akka HTTP), Scalatra (Akka Actors) and Finatra.
https://www.reddit.com/r/scala/comments/743zjv/web_framework/
Related
I'm developing a gateway that will be located between mobile web apps and web services on backend systems. The purpose of this gateway is to protect web apps against changes to backend web service api's, to introduce concurrency, transform messages, buffering, etc.
My proposed architecture is as follows:
Platform independent mobile web apps using PhoneGap (done)
Gateway is a web service using Scala for business logic and ZeroMQ for message passing (new)
Backends are existing web services (existing)
The gateway is purely responsible passing, translation, aggregation, etc. of messages and does not need to keep state or do user authentication at this point - it's simply responsible for being a single interface that knows how to talk to mobile apps on the one side and one or more services on the other side.
I'm strongly considering using Scala as the development language because it seems well suited for this type of application, but what would be the correct architecture for such a Scala service? I looked at frameworks such as Lift and Play and also considered doing a simple "java" based web service and just use Scala as to implement my business logic. I believe strongly in keeping things as simple as possible. I'm wary of complicated setups and thousands of lines of dead code in frameworks that may never be used. On the other side, limiting oneself to a 'role your own' solution and creating a lot of work and having to maintain code that may have been part of existing solutions is also not ideal.
Some things to consider: I'm the architect and developer, but my knowledge of Scala is limited to the first half of "Programming in Scala, Second Edition". Also, my time is very limited. Still, I want to get this right the first time.
I'm hoping that some clever gent or dame will provide me with insights to this type of solution and maybe a link or two to get started quick. I really need to get going FAST, but hope that the experience or insights of another professional could help me avoid pitfalls along the way. Any insights to development environments and tools will also be helpful. I have to develop on Mac (company rules) but will be deploying on Ubuntu server. I'm currently juggling between installs of Eclipse or Idea as IDE's and the scala compiler or sbt for building.
UPDATE
Thanks for all the potential answers below. I had a look at each and every suggestion and all of them have merit. The problem is now to bet on the right horse. Spray is possibly the simplest solution to the problem, but I also found Finagle. It seams like a stunning solution to my problem. I'm a bit concerned that it is built on top of Netty instead of Akka. Does anyone see any problem with that. I was hoping to keep my solution as purely Scala as possible, but Finagle appears to be the most mature of the lot. Any ideas?
It might be worth taking a look at Akka, which provides a lightweight framework for writing concurrent, fault-tolerant applications on the JVM, as well as useful built-in abstractions for writing web services. In addition, the Spray project looks like it could be useful for your purposes, providing HTTP server and client libraries on top of Akka (Although, unlike Akka itself, I haven't used this so myself so can't vouch for it).
If you're using a web service that is purely for other services, then an Akka based service like Spray or Blueeyes is probably your best bet. You can use Jerkson to do the JSON mapping to and from your case classes and use Akka-Camel to link to ZeroMQ.
As mistertim says, Akka is a good option. I'm biased, but I think Lift and its RestHelper is a fantastic way to go also (I've built several APIs for iPhone apps using Lift). Beyond those, I know several people who are very happy with Unfiltered.
Unfiltered is very interesting option if you want to keep it lightweight, as is not a full blown web framework.
To be honest, the documentation can use more detail, but to provide a web service you just write:
object MyService extends unfiltered.filter.Plan {
def intent = {
case req # GET(Path ("/myendpoint")& Params(params)) =>
for {
param1<-params("param1")
param2<-params("param2")
} yield ResponseString(yourMethod(param1,param2))
}
override def main(args:Array[String]) = unfiltered.jetty.Http.anylocal.filter(MyService).run();
}
Very useful if you don't want to use a framework and don't want to mix java/java annotations with Scala (otherwise, you have the usual java solutions)
Still, I would recommend to look into Akka if you think you think actors will fit your problem
If your system is middle-ware and get the things done quickly, then Spray will be a best. Spray was developed on top of Akka. Akka has ZeroMQ support.
in future if you are going to add some other web like module along with your middle-ware, then choosing Lift + Akka will be better because, Lift also provides Spray like web service stuff + it will be easy to start developing other modules.
You can choose SBT as your build, there are some project templates, template generation tools available, so you can get the project build very quickly.
In my experience , SBT + InteliJ Idea works well, have a look on sbt-idea plugin
Spray Project Template
Lift Project Template Generator
I'm getting into Scala, I find the object-oriented & functional paradigm combination really interesting.
So, I've read some tutorials about basic Scala, but now I want to get deeper into Scala as for web applications.
Anyone have tutorials, links, blogs or any kind of useful information?
definitely checkout play. its syntax is pretty sleek, has dynamic loading of classes (no restart of JVM when you make changes) and the APIs are pretty well thought.
Try Lift: http://liftweb.net/getting_started
I also recommend having a look at Lift since it uses Scala's strength very well. For example there's the embedded SiteMap DSL for structuring your site and an actor-based Comet implementation.
In this Interview with David Pollak he explains his reasons to start this project and (in short) Lift's benefits compared to Rails, Wicket, the Smalltalk web framework Seaside and Struts.
There are several Books about it (Lift in Action, The Definitive Guide to Lift: A Scala-based Web Framework), including two beeing available for free (Simply Lift by David Pollak, Exploring Lift including a very interesting chapter about Lift's internals).
When you are from a MVC background, you should read why Lift uses a different "View First" architecture for web apps. But there's a MVC Helper, too. See also chapter 13 in Simply Lift about that.
For a short look at different interesting code snippets I recommend the Seven Things Demo Application, but there also is another offical demo.
When you read some example view code you will probably encounter tags like <lift:surround with="default" at="content">. You would have to import the xml namespace to pass (x)html validators with such tags. Since this is not very designer-friendly a newer way to embed lift semantics in views is using the class attribute of a regular html element: <div id="main" class="lift:surround?with=default;at=content">
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I've just started learning Scala, and the first thing I'm going to implement is a tiny web application. I've been using Erlang for the last year to implement server-side software, but I've never wrote web applications before. It will be a great experience.
Are there web-frameworks for Scala except for Lift?
Don't get me wrong, Lift looks awesome. I just want to know how many frameworks there are so that I can then choose between them. It's always a good to have a choice, but I the only thing I found was Lift.
I'm very interested in Scala, but I have not used it yet, so with that caveat, the frameworks I am aware of that are not mentioned in HRJ's answer (Lift, Sweet, Slinky) are:
Scalatra, previously Step (on GitHub)
Play 2 (on GitHub)
Pinky
I wrote a blog post about this.
To summarise, some of the options are:
Lift
Sweet
Slinky
I finally found that none were suitable for me, and developed my own little "framework". (It is not open-source yet).
I like Lift ;-)
Play is my second choice for Scala-friendly web frameworks.
Wicket is my third choice.
Following is a dump of frameworks. It doesn't mean I actually used them:
Coeus. A traditional MVC web framework for Scala.
Unfiltered. A toolkit for servicing HTTP requests in Scala.
Uniscala Granite.
Gardel
Mondo
Amore. A Scala port of the Ruby web framework Sinatra
Scales XML. Flexible approach to XML handling and a simplified way of interacting with XML.
Belt. A Rack-like interface for web applications built on top of Scalaz-HTTP
Frank. Web application DSL built on top of Scalaz/Belt
MixedBits. A framework for the Scala progamming language to help build web sites
Circumflex. Unites several self-contained open source projects for application development using the Scala programming language.
Scala Webmachine. Port of Basho's webmachine in Scala, a REST-based system for building web applications
Bowler. A RESTful, multi-channel ready Scala web framework
Try Play Framework, which also support Scala.
One very interesting web framework with commercial deployment is Scalatra, inspired by Ruby's Sinatra. Here's an InfoQ article about it.
I find Unfiltered very interesting https://github.com/unfiltered/unfiltered.
It's mentioned in IttayD's list.
Here is a presentation about it http://unfiltered.lessis.me/#0
and the video http://code.technically.us/post/942531598/doug-tangren-presents-the-unfiltered-toolkit-for
Also here there is an article with more info http://code.technically.us/post/998251172/holding-the-parameter
It must be noted that there is also a considerable interest in Wicket and Scala. Wicket fits Scala suprisingly well. If you want to take advantage of the very mature Wicket project and its ecosystem (extensions) plus the concise syntax and productivity advantage of Scala, this one may be for you!
See also:
Some prosa
Presentation
Some experience with Wicket and Scala
Announcments with reference to the project for the glue code to bind Scala closures to models
Play is pretty sweet.
It is now production ready. It incorporates: a cool template framework,automatic reloading of source files upon safe, a composable action system, akka awesomeness, etc.
Its part of the Typesafe Stack.
Having used it for two projects, I can say that it works pretty smoothly and it should be something to consider next time you are looking to learn new web frameworks.
I tend to use JAX-RS using Jersey (you can write nice resource beans in Scala, Java or Groovy) to write RESTul web applications. Then I use Scalate for the rendering the views using one of the various template languages (JADE, Scaml, Ssp (Scala Server Pages), Mustache, etc.).
There's a new web framework, called Scala Web Pages. From the site:
Target Audience
The Scala Pages web framework is likely to appeal to web programmers who come from a Java background and want to program web applications in Scala. The emphasis is on OOP rather than functional programming.
Characteristics And Features
Adheres to model-view-controller paradigm
Text-based template engine
Simple syntax: $variable and <?scp-instruction?>
Encoding/content detection, able to handle international text encodings
Snippets instead of custom tags
URL Rewriting
Prikrutil, I think we're on the same boat. I also come to Scala from Erlang. I like Nitrogen a lot so I decided to created a Scala web framework inspired by it.
Take a look at Xitrum. Its doc is quite extensive. From README:
Xitrum is an async and clustered Scala web framework and web server on top of Netty and Hazelcast:
It fills the gap between Scalatra and Lift: more powerful than Scalatra and easier to use than Lift. You can easily create both RESTful APIs and postbacks. Xitrum is controller-first like Scalatra, not view-first like Lift.
Annotation is used for URL routes, in the spirit of JAX-RS. You don't have to declare all routes in a single place.
Typesafe, in the spirit of Scala.
Async, in the spirit of Netty.
Sessions can be stored in cookies or clustered Hazelcast.
jQuery Validation is integrated for browser side and server side validation.
i18n using GNU gettext, which means unlike most other solutions, both singular and plural forms are supported.
Conditional GET using ETag.
Hazelcast also gives:
In-process and clustered cache, you don't need separate cache servers.
In-process and clustered Comet, you can scale Comet to multiple web servers.
Follow the tutorial for a quick start.
There's also Pinky, which used to be on bitbucket but got transfered to github.
By the way, github is a great place to search for Scala projects, as there's a lot being put there.
I'd like to add my own efforts to this list. You can find out more information here:
brzy framework
It's in early development and I'm still working on it aggressively. It includes features like:
A focus on simplicity and extensibility.
Integrated build tool.
Modular design; some initial modules includes support for scalate, email, jms, jpa, squeryl, cassandra, cron services and more.
Simple RESTful controllers and actions.
Any and all feedback is much appreciated.
UPDATE: 2011-09-078, I just posted a major update to version 0.9.1. There's more info at http://brzy.org which includes a screencast.
Both Sweet and Slinky seem to be unmaintanted for about a year. Sweet Maven repo sweetsoftwaredesign.com is dead so there's even no way to download dependencies.
Note: Spiffy is outdated.
<plug>
Spiffy:
is written in Scala
uses the fantastic Akka library and actors to scale
uses servlet API 3.0 for asynchronous request handling
is modular (replacing components is straight forward)
uses DSLs to cut down on code where you don't want it
supports Scalate and Freemarker for templating
Spiffy is a web framework using Scala, Akka (a Scala actor implementation), and the Java Servlet 3.0 API. It makes use of the the async interface and aims to provide a massively parallel and scalable environment for web applications. Spiffy's various components are all based on the idea that they need to be independent minimalistic modules that do small amounts of work very quickly and hand off the request to the next component in the pipeline. After the last component is done processing the request it signals the servlet container by "completing" the request and sending it back to the client.
https://github.com/mardambey/spiffy
</plug>
You could also try Context. It was designed to be a Java-framework but I have successfully used it with Scala also without difficulties. It is a component based framework and has similar properties as Lift or Tapestry.
I have stumbled upon your question a few weeks back, but since then also learned about Circumflex. This is a nice, minimal framework that is therefore easy to learn, and it has pretty good documentation available as well.
Beside it's minimal-ness, it also claims to work well with other libraries and lets you use your own implementation of things when you need it.
I am about to start a new webapp that will be running on P/GAE and reagarding the front end we would like to use one of the mentioned frameworks (GWT, SC, Cap).
Which one do you think is the most developer friendly? It seems that Cappuccino looks stunning but you have to learn Obj-J. Sproutcore seems nicer (since there is only JS) but I could not say I am impressed with the docs plus some of the demos are broken.
GWT on the other hand is very mature but I have the feeling that using Java may slow you down as you cannot use some of the JS quirks on the other hand there is vibrant ecosystem around it.
I think the answer depends on what type of developer are you?
For me, I'm comfortable with Javascript and like the ability to manipulate the browser DOM so that I can implement features that may not be in the framework. That's why I prefer Sproutcore.
Checkout http://www.infoq.com/news/2009/09/sproutcore-1-0.
I have to agree with you that documentation is limited. However, I've found wiki useful and the community really helpful.
GWT is a very nice choice if you're using GAE-Java because then you can develop server-side and client-side in the same language. If you're using Python on the server-side, you won't be able to use GWT's simple RPC calls to serialize objects to/from the browser. It's still a nice framework though.
GWT does allow you to write JS-native code if needed, so you can "use some of the JS quirks" if you need to.
One warning: GWT apps are totally AJAX, so they can't really be seen by search engines (a general problem with AJAX, not with GWT specifically)
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I've just started learning Scala, and the first thing I'm going to implement is a tiny web application. I've been using Erlang for the last year to implement server-side software, but I've never wrote web applications before. It will be a great experience.
Are there web-frameworks for Scala except for Lift?
Don't get me wrong, Lift looks awesome. I just want to know how many frameworks there are so that I can then choose between them. It's always a good to have a choice, but I the only thing I found was Lift.
I'm very interested in Scala, but I have not used it yet, so with that caveat, the frameworks I am aware of that are not mentioned in HRJ's answer (Lift, Sweet, Slinky) are:
Scalatra, previously Step (on GitHub)
Play 2 (on GitHub)
Pinky
I wrote a blog post about this.
To summarise, some of the options are:
Lift
Sweet
Slinky
I finally found that none were suitable for me, and developed my own little "framework". (It is not open-source yet).
I like Lift ;-)
Play is my second choice for Scala-friendly web frameworks.
Wicket is my third choice.
Following is a dump of frameworks. It doesn't mean I actually used them:
Coeus. A traditional MVC web framework for Scala.
Unfiltered. A toolkit for servicing HTTP requests in Scala.
Uniscala Granite.
Gardel
Mondo
Amore. A Scala port of the Ruby web framework Sinatra
Scales XML. Flexible approach to XML handling and a simplified way of interacting with XML.
Belt. A Rack-like interface for web applications built on top of Scalaz-HTTP
Frank. Web application DSL built on top of Scalaz/Belt
MixedBits. A framework for the Scala progamming language to help build web sites
Circumflex. Unites several self-contained open source projects for application development using the Scala programming language.
Scala Webmachine. Port of Basho's webmachine in Scala, a REST-based system for building web applications
Bowler. A RESTful, multi-channel ready Scala web framework
Try Play Framework, which also support Scala.
One very interesting web framework with commercial deployment is Scalatra, inspired by Ruby's Sinatra. Here's an InfoQ article about it.
I find Unfiltered very interesting https://github.com/unfiltered/unfiltered.
It's mentioned in IttayD's list.
Here is a presentation about it http://unfiltered.lessis.me/#0
and the video http://code.technically.us/post/942531598/doug-tangren-presents-the-unfiltered-toolkit-for
Also here there is an article with more info http://code.technically.us/post/998251172/holding-the-parameter
It must be noted that there is also a considerable interest in Wicket and Scala. Wicket fits Scala suprisingly well. If you want to take advantage of the very mature Wicket project and its ecosystem (extensions) plus the concise syntax and productivity advantage of Scala, this one may be for you!
See also:
Some prosa
Presentation
Some experience with Wicket and Scala
Announcments with reference to the project for the glue code to bind Scala closures to models
Play is pretty sweet.
It is now production ready. It incorporates: a cool template framework,automatic reloading of source files upon safe, a composable action system, akka awesomeness, etc.
Its part of the Typesafe Stack.
Having used it for two projects, I can say that it works pretty smoothly and it should be something to consider next time you are looking to learn new web frameworks.
I tend to use JAX-RS using Jersey (you can write nice resource beans in Scala, Java or Groovy) to write RESTul web applications. Then I use Scalate for the rendering the views using one of the various template languages (JADE, Scaml, Ssp (Scala Server Pages), Mustache, etc.).
There's a new web framework, called Scala Web Pages. From the site:
Target Audience
The Scala Pages web framework is likely to appeal to web programmers who come from a Java background and want to program web applications in Scala. The emphasis is on OOP rather than functional programming.
Characteristics And Features
Adheres to model-view-controller paradigm
Text-based template engine
Simple syntax: $variable and <?scp-instruction?>
Encoding/content detection, able to handle international text encodings
Snippets instead of custom tags
URL Rewriting
Prikrutil, I think we're on the same boat. I also come to Scala from Erlang. I like Nitrogen a lot so I decided to created a Scala web framework inspired by it.
Take a look at Xitrum. Its doc is quite extensive. From README:
Xitrum is an async and clustered Scala web framework and web server on top of Netty and Hazelcast:
It fills the gap between Scalatra and Lift: more powerful than Scalatra and easier to use than Lift. You can easily create both RESTful APIs and postbacks. Xitrum is controller-first like Scalatra, not view-first like Lift.
Annotation is used for URL routes, in the spirit of JAX-RS. You don't have to declare all routes in a single place.
Typesafe, in the spirit of Scala.
Async, in the spirit of Netty.
Sessions can be stored in cookies or clustered Hazelcast.
jQuery Validation is integrated for browser side and server side validation.
i18n using GNU gettext, which means unlike most other solutions, both singular and plural forms are supported.
Conditional GET using ETag.
Hazelcast also gives:
In-process and clustered cache, you don't need separate cache servers.
In-process and clustered Comet, you can scale Comet to multiple web servers.
Follow the tutorial for a quick start.
There's also Pinky, which used to be on bitbucket but got transfered to github.
By the way, github is a great place to search for Scala projects, as there's a lot being put there.
I'd like to add my own efforts to this list. You can find out more information here:
brzy framework
It's in early development and I'm still working on it aggressively. It includes features like:
A focus on simplicity and extensibility.
Integrated build tool.
Modular design; some initial modules includes support for scalate, email, jms, jpa, squeryl, cassandra, cron services and more.
Simple RESTful controllers and actions.
Any and all feedback is much appreciated.
UPDATE: 2011-09-078, I just posted a major update to version 0.9.1. There's more info at http://brzy.org which includes a screencast.
Both Sweet and Slinky seem to be unmaintanted for about a year. Sweet Maven repo sweetsoftwaredesign.com is dead so there's even no way to download dependencies.
Note: Spiffy is outdated.
<plug>
Spiffy:
is written in Scala
uses the fantastic Akka library and actors to scale
uses servlet API 3.0 for asynchronous request handling
is modular (replacing components is straight forward)
uses DSLs to cut down on code where you don't want it
supports Scalate and Freemarker for templating
Spiffy is a web framework using Scala, Akka (a Scala actor implementation), and the Java Servlet 3.0 API. It makes use of the the async interface and aims to provide a massively parallel and scalable environment for web applications. Spiffy's various components are all based on the idea that they need to be independent minimalistic modules that do small amounts of work very quickly and hand off the request to the next component in the pipeline. After the last component is done processing the request it signals the servlet container by "completing" the request and sending it back to the client.
https://github.com/mardambey/spiffy
</plug>
You could also try Context. It was designed to be a Java-framework but I have successfully used it with Scala also without difficulties. It is a component based framework and has similar properties as Lift or Tapestry.
I have stumbled upon your question a few weeks back, but since then also learned about Circumflex. This is a nice, minimal framework that is therefore easy to learn, and it has pretty good documentation available as well.
Beside it's minimal-ness, it also claims to work well with other libraries and lets you use your own implementation of things when you need it.