Selected Sessions from
RailsConf 2007
Jerry Richardson, jerry@jerryr.com
Chief Technologist, iBlinkink

Clean Code
• incremental improvement
• always check code in better than you checked it out
• never let the sun set on bad code
• test first => \"test obsessed\"
• provides the necessary flexibility

Robert Martin
“I am not allowed to make a
change that breaks the
system. Every tiny change I
make will keep that system
working.”

Let’s Refactor
• Principle of least surprise
• tiny steps => change each variable type, then run the
tests
• shrink the granularity of your development
• create a barrier between things that change and things
that don't

Is it worth it?
• crafting good solutions
• clean it up as soon as it gets messy => the dinner
parable: get up and walk away from the dinner table or
keep your dishes clean all the time
• bad schedules, requirements, team dynamics can all be
fixed but bad code rots, ferments and becomes an
inexorable weight that drags the team down.

Professional Behavior
• The \"Green Band\"
• Professionals write their tests first
• Professionals keep their code clean
• Professionals know that the only way to go fast is to go
well.
• making things a little bit nicer => the check-in rule

Doing REST Right
Recognize rest principles in what you're
already doing. Apply them to your
whole process.
Orthodoxy (right teaching, right beliefs,
right thoughts) versus Orthopraxy
(right practice)

Orthodoxy
• Roy Fielding's Thesis defined REST (Representational
State Transfer)
• All models are wrong but some are useful. - George
Box
• Leaky Abstractions
• Diagrams are wrong but useful in representing
complex, real-world systems. Same thing with
abstractions.

REST isn’t...
• Pretty URLs
• CRUD
• respond_to
• map.resources
• a protocol - http
• an architecture

REST is...
• the architectural style of the web
• Roy Fielding's Hierarchy
• Abstract => Communication Theory
• REST
• Web Architecture
• Concrete => Implementation

REST is...
• A resource is anything that can be named
• A resource is an object with a couple of contraints -
can only implement a very small number of methods,
same for all resources
• you don't access a resource -- you access a
representation of it. (respond_to with format.xml,
format.txt, etc.)

Orthopraxy
• Identification - URL
• Interaction (Method or Verb)
• Safety - has no side effects, incurs no obligations (get
is the only method that is safe by definition)
• idempotent -- applying a function once returns the
same value as applying it multiple times (get, put and
delete)

Post
• post is neither safe nor idempotent => reserve it for
when you need it

Content, Body of Request
• REST pushes all of the complexity into content, out of
identification and interaction
• messages should be use standards and be self-
descriptive, like html
• look for content types that map to your application
domain - instead of to_xml, use an established type for
users => do vcard instead of your arbitrary user xml

Adding Tests to
Legacy Rails Apps
Most first-time Rails apps are built
before a developer understands their
importance. Testing is painful in many
frameworks and ignored when many
people switch to using rails.

Starting
• Don't do it all at once. It won't work.
• first, run rake
• mysqladmin -u root create appname_test
• Use Migrations
• Scaffolding is broken => those tests don't work.

One Step at a Time
• find a bug, write a test
• refactor a method, write a test
• treat each method as a box - don't get pulled in to
testing everything
• test one thing at a time
• Test: what goes in? what comes out? (returning
something in the method)

Rake or Direct Testing
• rake or direct testing
• rake testing: rake test:uncommitted
• direct: ruby test_file.rb -n test_name to run one test
in a specific file

Build Tests from Logs
• Parameters then reproduce actual requests.

What To Test
• right response code
• correct template
• variable assignment
• assignment of desired object

Me.
Questions?

Image Credits
• DHH
http://flickr.com/photos/x180/503574487/
• Robert Martin
http://flickr.com/photos/x180/503608084/
• Scott Raymond
http://flickr.com/photos/keeg/511239686/
• Evan (Rabble) Henshaw-Plath
http://flickr.com/photos/x180/474128166/
• Me
http://flickr.com/photos/jackdanger/502998700/