|Haskell Web Development|
The web development community in Haskell has recently had a large boost in activity, resulting in a plethora of choices in libraries. As usual, a breadth of options is a double edged sword: you can choose the tools more to your style, but it is harder to find quality tools.
Rather than one framework to rule them all, Haskell provides several options. On this page we show a non-inclusive list of options to help the Haskell web programming newbie find which libraries and frameworks work together.
Please join us on the mailing lists to discuss web development in Haskell.
Option 1: Happstack
Happstack is a complete web framework. It is organized as a suite of libraries including:
- happstack-server: an integrated HTTP server, routing combinators, fileserving, etc
- happstack-data: datatype serialization and migration support
- happstack-state (aka macid): an (optional) powerful NoSQL ACID storage system with native support for Haskell types and replication
It also includes integration with many 3rd party libraries including:
- templating: Blaze HTML combinator library, Hamlet, HSP, HStringTemplate, Heist, and more
- forms: Formlets
- routing: web-routes type-safe urls and routing
- databases: can be used with most Database interfaces with no special support required
Happstack is primarily intended for use on VPS or dedicated hosts, but can be used with CGI via FastCGI or hack.
See the Happstack Home Page for more information and to learn how to get support via IRC and mailing lists.
Option 2: Yesod + Warp
Yesod is a full-featured web framework. It takes a modular approach to development, so many parts of the framework such as Hamlet and Persistent are available as standalone packages. However, put together, Yesod provides you with solutions for templating, routing, persistence, sessions, JSON, authentication/authorization, and more. Yesod's major guiding principle is type safety: if your application compiles, it works.
Yesod is very well documented through the Yesod book. Work is being done on an constant basis to improve the documentation status, but the first ten chapters (covering all the basics) are already done, so it should be easy to get started.
Yesod is built on WAI, or the Web Application Interface. This is similar to WSGI in Python or Rack in Ruby. It provides a single interface that all applications can target and work on multiple backends. Backends exist for CGI, FastCGI, SCGI, development server (auto-recompile) and even a Webkit-powered desktop version.
But the premier backend is Warp: a very simple web server which, at the time of writing, is the fastest Haskell has to offer. You can read more in its release announcement and see some followup benchmarks. Warp is already powering Yesod; some other major players that are planning a move are Hoogle and Happstack.
You can see a list of Yesod-powered sites and packages, or check out the source code for Haskellers. Most discussions for Yesod take place on the web-devel list, so feel free to join in and ask any questions you have, the Yesod community is very beginner-friendly.
Option 3: (Fast)CGI + WAI + Yesod
This option is similar to Option 2 except we use a webserver like nginx, lighttpd, or Apache. These servers would communicate with your web applications using CGI or FastCGI. See wai-handler-fastcgi for a library which connects FastCGI with the WAI interface. A search for wai-handler shows the various options available. See the deployment chapter of the Yesod book to see how to configure the various servers and FastCGI to host WAI applications.
Option 4: Turbinado
TODO: Explain about Turbinado since I don't know anything about it right now
Option 5: Salvia
TODO: Explain about Salvia
Option 6: Snap + custom code + libraries
In this option, you would write your website to directly use the Snap server. Instead of using an interface like WAI, you would receive requests and generate responses directly to the snap server. Look through the Snap documentation to get started using this option. There are a plethora of libraries to help you:
- Snap's templating library called Heist, some other templating library or the Blaze HTML combinator library.
- Some database Access or Persistence library.
- The Formlets library for coding forms.
- See Libraries for a list of some other helpful libraries.
Option 7: (Fast)CGI + custom code + libraries
This is very similar to the previous option, but using CGI or FastCGI to talk to another web server. See this tutorial on simple CGI programming for a simple example.
Something not listed on this page. There are several web frameworks or libraries in various stages of development like Lemmachine, Haskell on a Horse, mohws, loli, plus probably others which are not listed.