Leverage the World Wide West with Farwest

Coming soon to a desert near you.

Loïc Hoguin - @lhoguin

Erlang Cowboy and Nine Nines Founder

How soon?

• Farwest is the result of months of research
• It still needs a few months of development
• Early feedback is more than welcome

Current solutions in Erlang

Nitrogen

• Web development for Erlang developers
• HTML built using Erlang records
• Built-in JS for many components and actions

ChicagoBoss

• Erlang development for Rails developers
• ErlyDTL templates
• No constraints on frontend libraries used

Zotonic

• The Erlang CMS
• Big plugin-based architecture, with ErlyDTL templates
• Many constraints on how the development should be done

Lightweight server solution

• Choose your own adventure server
• No constraint on any frontend or backend libraries
• A lot more work to set everything up

Problems

Erlang developers suck at Frontend

• They know how to write code, not UI
• Writing HTML in Erlang doesn't make them better
• UIs created by Erlang developers generally suck
• The Erlang developer should never touch frontend code

Frontend developers and Erlang

• They don't know what Erlang is
• They just need templates and assets
• They need to be able to write or update the templates
• They should do so without any Erlang knowledge

They have different concerns

• These concerns shouldn't overlap
• They need a common language to exchange information

REST is the key

• Erlang developers know REST
• Frontend developers already use REST APIs
• Make REST the common language between both sides

Farwest

Farwest for Erlang developers

• Strictly work only on backend logic
• No HTML, CSS or JS; it's the Frontend guy's job!
• REST API developer
• Get data in and out, that's it
• Same old Cowboy REST development you're used to do

Farwest is for Frontend developers

• Because they make your app pretty and easy to use
• None of the following Farwest features require Erlang knowledge

Installation and setup

• Install Erlang
• Download and untar a blank project template
• Start the server with ./start.sh
• This gives you a link to the integrated development interface

Continuous development

• Automatic code recompilation and reload
• Including templates, CSS and JS
• Only a refresh of the page is needed to view the changes

Built for REST

• Development tools for REST, with a Web UI
• Javascript libraries to simplify REST manipulation
• Crawlers can still retrieve your content using GET

Backend API documentation

• Automatically generated
• Partially built using the resources exports
• Partially built from the edoc comments
• Available through the API explorer tool

Bullet enabled

• Always connected bidirectional stream with the server
• Receive server events as soon as they happen
• Events are mapped to JS callbacks
• Reply directly without opening a new connection

REST over Bullet

• Call the API over the Bullet stream
• Request is sent as JSON, converted to a Req object, then dispatched
• Request is asynchronous, similar to jQuery.ajax()

Routing

• Uses Cowboy's dispatch list mechanism
• Includes a tool for configuring the dispatch list
• Dispatch list is reloaded live

Quick application scaffolding

• Predefined API enabled by default
• /data/: direct data storage access
• /dispatch/: direct dispatch list access
• /env/: direct environment data access
• /farwest/: development tools Web UI

Map URIs to data

• Map a URI to a scaffolding resource handler
• Resource handler receives a list of data queries
• URI components and query string can be used in queries
• Templates receive the queried data
• Configurable using the dispatch and query Web UIs

Not just scaffolding

• You can choose to keep these features enabled
• After adding some authentication of course
• They let the end user extend your application
• Like a wiki, but with separate data and templates

Remember?

• None of this requires Erlang knowledge
• They can write their application without knowing Erlang
• They can write their application before the backend is ready
• They may not even need a custom backend API

Farwest is still Erlang

• Concurrent
• Fault-tolerant
• Easily distributed
• And one more thing...

Live frontend upgrades

• Available as part of release upgrades
• Upgrade the page's CSS, JS or media files live
• When not possible, a callback can be called instead
• This one obviously requires an Erlang developer

Technical overview

Modular Farwest

• Base Farwest contains the core, tools and scaffolding
• Plugins are rebar dependencies
• Write your application as a standard OTP application
• Or write many Farwest plugins for reusability

Farwest plugins

• Plugins are OTP applications
• At startup, plugins register themselves with Farwest
• They provide resources, OTP services, assets, tools

OTP compliant

• Generate OTP releases of your applications
• Upgrade Farwest or its plugins
• Connect several Farwest nodes

Made for the web

• Automatic minifying and merging of CSS/JS files
• User authentication (plugins)
• Internationalization and unicode support

Dependencies

• Cowboy, Bullet, Sheriff, Goldrush/Saloon
• ErlyDTL, JSX
• Gproc
• Bootstrap, jQuery
• Undecided storage backend

Undependencies

• You don't have to use most dependencies
• Farwest does not enforce how you build the application

License

• ISC License (BSD simplified)
• Same as Cowboy

Timeline

• March 29th, 2012: This talk
• April 2nd, 2012: First commits
• EUC, 2012: Alpha
• London, 2012: Beta

You can help

• Follow the project
• Try it out as soon as it becomes available
• Send patches
• Sponsor the project

Links

• https://github.com/extend/farwest
• http://ninenines.eu
• #erlounge on Freenode

Questions?