planet jerry! - Home

My Great Lakes Ruby Bash Notes

2008-10-15T20:23:00Z

Ann Arbor, Michigan, October 10, 2008

Predicting The Future: A Perspectives on Ruby and Rails – Winston Tsang (9:10am)

Be Sensitive to areas from which change is emerging. Be aware of what is going on around you.

A Look into the Past at Problems People Had

Packages (Jars, RPM’s)- Ruby’s Gems solved the problem, plus documentation using ‘gem server’
Testing (required immense configuration) – Rails? Tests are baked right in. autotest takes it to the next level of automation
Deployment – Capistrano solves it for rails apps

“The future is here, it’s just not evenly distributed yet.” – William Gibson

Using Active Scaffold – Joseph Faisal Nusairat (9:30am)

Production Quality Scaffolding
Ajaxified/Restful/Sexy
3rd Party Plugins Available

Add the active_scaffold plugin from the git repo
”<%= active_scaffold_includes %>” in your layout


active_scaffold :keyword do |conf|
    conf.create.columns = [:name, :description]
    conf.update.columns = [:name, :description]
    conf.list.columns = [:name, :description]
    conf.create.link.label = "Add Keyword" 
    conf.actions.exclude :show
end

can use a global config to ignore columns
observes validations from ActiveRecord
search comes for free on string fields
can add live searching with a config
can add new children (categories, keywords)
can get prettier calendars as plugins
easy to add column sorting

Useful for admin site areas, less so for front-end customer-facing areas
Tempo on integrallis.com is an example in use

Hacking the Mid-End: Advanced Rails UI Techniques – Michael Bleigh (10:00am)

Intridia => [:crowd_sound, :media_plug, :present_ly]

Define Mid-End

MC – Backend developers
V – Designers and Frontend Developers
MVC+I (I is for Interaction) => Mid-End Developer is all about Abstraction
- Delivering Smart Partials to the Front-End developer
- Deliver a Smart Helper to the Back-End Developer
- Get XHTML/CSS from the Front-End Developer
- Get App/Structure from the Back-End Developer

Mid End Should Be

Fast – perception is key, must feel fast
Accessible – to as many people as possible (screen readers, color contrast) and to Multiple Devices
- Unobtrusive Javascript is an automatic best practice – rails is imperfect here
Intuitive – Leverage User Expectations
- is this a web app or a desktop app on the web? No wrong choice, but web apps are right.
Responsive – immediate or near-immediate feedback after an action that action is underway or completed

Solving Midend Problems

Helpers – Block-Accepting
Partials
jQuery
LowPro (makes prototype less obtrusive)

The Approach

build it without js
abstract UI into helpers and partials
add unobtrusive javascript

Avoid the “Unknowing, What’s Going On” Stage
Add generate.html.erb (our old show.html.erb)
Show action becomes – “TPS Reports May Take Up to 10 seconds to Generate”

delayed_loader.js


DelayedLoader = $.klass({
    initialize.function() {
        link = this.element.find('a.continue');
        this.url = link.attr('href');
        link.replaceWith('< image of spinner >');

        var element = this.element;
        $.get(this.url, function(data) {
            element.html = data;
        });
    }
});

pre-load all tabs for js-users, then show content as necessary.
remove ‘current’ class from non-current tab names

Problem: Updating Parts of a Page in Ajax, But not Updating the “Time Ago” for earlier entries

time ago in words for js
add the actual time as a title
reparse times from titles using Date.update_relative_times()

Usability on Rails: Tips & Tricks for Creating Passionate Users – Larry Karnowski (11:00am)

Don’t Test Your Views

Treat views as Data, not Code
Extract all code from view for testing
Validate Your Views for Testing
Test Your Helpers – ActionView::TestCase

Tarantula – spiders your app using webrick in memory

login
follow_redirect!
tarantula_crawl(self) – fuzzy spider – follows links and hits forms with fuzzy data

safe_erb – disallows potentially-tainted strings
unit_controller – narrows scope of testing to the controller only

Into the Middle of Things (In Media Res)

Customers are not at the beginning of the process. By the time we meet them, they have a problem.
They don’t love software, They want to kick ass.
Make them feel empowered.

Flashback! to the beginning

What do we need to build?
- Start with a User Interview
- Learn the user’s language
- stay agile
- be aware of user needs vs. their supervisors/employers (if I was talking to a real user, this will be a better app)
What is it going to look like?
- Start with pen & paper sketches – different part of the brain (cheap, easy, permission to contribute is implicit)
- Find the best user experience first
  - learn the intent of the app
  - don’t consider implementation initially
  - 3-4 wireframes => it takes a lot of bad ideas to get to one good one
  - Adjust scope to reality
  - OmniGraffle
- HTML/CSS Mockups
  - user serve plus erb

The Engineer’s Fallacy – People are not logical, they are emotional. Engineers don’t know that.

User Behavior

Data Smells
Non-Linear Scanning of Pages
Ad Blindness
Technology Myths & Superstitions

Agile User Testing – Coming Soon

forget big labs, video, audio
cheap, cheap, cheap
try to get real users (office manager is more computer savvy), but grade on a curve
neighbors, spouses, Mom
need three testers, but rinse & repeat

Keep vocabulary consistent across multiple uses inside the app – same word – don’t use synonyms

“Get It” Testing

earlier
sketches wireframes, mockups
“i spy”, not “show & tell” – tell me what you see.

Think aloud testing

determine use cases
emphasize that software is being tested, not the user
after every iteration if possible, but once a month is great

Quick Tips

show users where they are
- mileposts
- bread crumbs
reduce memory load (we have 2x-10x the memory they do)
don’t leave ‘em wondering
NEVER throw away your user’s work

Good Error Messages

context aware
- Rails validation error messages are not context aware (being in the models) and are cumbersome with associations
plain english
suggest their own fix

Wicked Messenger – Creates a Hierarchy of Error Messages

Help Doesn’t

people don’t read until after they screw up
use JIT help

We aren’t there to help when the big battle is underway. We are the supernatural aid to the hero.

“Don’t make me think” – Steve Krug “The Back of the Napkin” – Dan Roam

Boxesandarrows.com adaptivepath.com codinghorrow.com

github.com/lawjoskar

HAML => “I don’t want input from a designer, ever.”

Playing it Safe – How to write library friendly code in Ruby – Jim Weirich (1:00pm) (or How to Avoid Being Leeroy Jenkins)

Playing well with Others – Does it Matter? Application (No) vs. Library (Yes)

“At least I have chicken.”—Leeroy Jenkins

Tips for Playing it Safe

protect against accidental problems
Use Namespaces (node => put it in a module)
Choose Project Name Carefully (check gems, github, RubyForge and don’t duplicate those)
Avoid Top Level Functions and Constants (put them in the module)
Avoid Modifying Existing Classes – Prefer adding over modifying (adding rake_dup in kernel instead of modifying Kernel::dup),
When adding use project scoped names (scoped with the “rake” name to reduce conflicts)
you be nice and check for conflicts – “unless instance_methods.include? ‘ext’” – ask first, then add
Selector Namespaces (coming in Ruby 2.0 per Matz)

Replacing Behavior

allow backwards compatibility
const_missing to return Rake::Task and give you a warning

Hooking Tips

go back and invoke the original const_missing – chain your hook behavior
only handle your special cases
limit the scope of your hook, esp. for method_missing (handle your methods then hand it up the chain)

kirby problem vs. whiny_nils => make it better than the existing method

Require Hooks

ruby_gems overrides require
- try original require
- adds a rescue on the LoadError to search for the gem, adds it to the load path
- try original require and raise the original require’s error if it still fails

Preserve the Original Behavior

Understand and Obey Contracts between Callers and libraries (Design by Contract)

pre-condition: What Must be true before a method is called (for Math.sqrt, n >= 0)
post-condition: What Must be true after a method is called (for Math.sqrt, (Result*Result-n).abs < 0.001)
New Behavior Added Must have the same or weaker precondition
New Behavior Added Must have the same or stronger postcondition (ReallyAccurate.sqrt(n))
Bertrand Meyer => Require no more. Promise no less.

Summary

Be Polite with Global Resources
Respect and Obey Contracts when Duck Typing

New Features in Test::Unit 2.0 – Daniel Berger (2:00pm)


require 'rubygems'
gem 'test-unit'
require 'test/unit'

assert_true, assert_false, assert_boolean
omit, omit_if, omit_unless => skips a test good for platform-specific , omissions are tracked separately in the output
pend – a todo with annoyance
notify – maybe as a test debugger, but it is tracked
startup and shutdown – analogous to setup and teardown, run once per test case


def self.startup
    # anything you need to only do one time
end

def self.shutdown
    # anything you need to only do one time
end

multiple setup & teardown – organize setups better if they start to get too long


setup # first
def foo
end

setup # second 
def foo_2
end

better diff output
priority mode reduced test time – runs all failed tests plus 50% of successful ones (priority :must and it will always run)
colorized output

Behavior Driven Development with Cucumber – Brandon Keepers (2:30pm)

Language is a barrier between developers and clients
User Stories Capture Intent of the Feature
why, who then feature
Quality: works as expected
After gaining confidence, Testing can become part of the design process, then Specifying Behavior Completes the Evolution

Cucumber

rbehave, then rspec story runner, then cucumber
runs in ruby but can be used to test other web apps
is a rake file to run the features


Feature (top level story): Manage Companies
    In order to keep track of companies
    a user
    should be able to manage companies

    Scenario: Add a New Company
        Given I am logged in
        When I create a new company named Acme
        Then I should see that a company named Acme exists

Don’t implement login as the first feature

Into the Limelight: An Introduction to a Ruby Rich Client Framework – Paul Pagel (3:15pm)

Metawhat? A look into the mysterious metaclass Brandon Dimcheff (3:45pm)

Metaclass, Singleton Class, Eigenclass, Virtual Class
an object is a pointer to its class
a class has a collection of methods and a super pointer

method dispatch

dereference my class pointer
check the methods table for my method
call the method or move on to the superclass and search there if it doesn’t exist

instance-specific values causes a singleton class to be created

a metaclass is a singleton class of a class

all classes have metaclasses

On Diversification

2008-07-25T21:25:00Z

I’ve been all over the map on diversification. Initially, I was in mutual funds and tracking stocks. In downward spirals, they all gravitated lower. Breadth in a bear market was a guaranteed way to lose money. It seems like individual equities are the only thing that escaped the downdrafts.

Lately, I have been playing for quick pops – looking for a big move in 48-72 hours, usually around earnings or extraordinary events. When I find one that looks promising, I go big and try to maximize the profit generated.

The guys that send the checks from my employer to my 401K account have noticed the same trend in my investing. They are none too keen on my style, but they can’t knock my results.

Class of 90? Let's Reunite

2008-04-25T17:28:00Z

Members of the Warsaw Community High School Class of 1990: Planning has begun on our 20-year reunion.

So far, we have a group on facebook (since that is free) where some of the discussions are taking place.

http://www.facebook.com/group.php?gid=26729364664

The first date we’ve discussed is June 19th, 2010. Anybody have any problems with that right now?

How different are McCain and Hillary?

2008-03-11T14:48:00Z

Would a Hillary presidency be substantially different from a McCain White House?

Will she succeed in bringing health care to the uninsured? She didn’t the first time she tried. The bumbling Clinton administration set back the cause of universal coverage by a generation.

Will she reign in the power of the presidency and roll back the unconstitutional pattern of behavior blazed by the Bush administration? This is not a cause that I have heard her take up. Her inability to take a stand against torture is an implicit endorsement of its use. In this area, I think McCain may scratch my anti-torture itch more effectively than Clinton.

Will she take up the cause of the poor and fight poverty? Welfare reform under Clinton the 1st was a pure capitulation to Republican interests after taking a beating in 1994.

Will gay and lesbian Americans be made whole citizens under the law under Clinton the 2nd? “Don’t ask, don’t tell” is a politician’s answer to a moral question.

We support Obama because he will change America and Americans for the better. For Barack, becoming President is a means to an end. The end we seek is a better nation.

Winning the White House as an end in itself, exclusively for the sake of beating the Republican party, is insufficient. Winning without conscience is losing.

Merlin Mann Inbox Zero Video - Notes

2007-10-18T17:35:00Z

build walls where none existed

knowledge workers – add value to information

time and attention are finite, most vital resources

multitasking is a myth

honor where your time and attention go

demands on time and attention are infinite

ultimately – make sure stupid blocks don’t get in the box

Manage Actions – map time and attention to the things you consider important

Prior Art: GTD concept of processing – advanced common sense

Email is just a medium
one place for anything
process to zero – every time you check your email
convert to actions

Processing

more than checking
deal with the problem
less than responding

Answer the question: So What? What actions do I have to take as a result of this email?

Don’t just take orders – Make Sandwiches

Limited Number of Options – 5 Verbs (in order of desirability):

delete (or archive)
- a single folder
delegate (horizontally or vertically)
- with a follow-up tickler (2 week reminder, @waiting_on)
respond
- 1 or 2 line replies
defer – respond, but outside work first
- to_respond folder
- inbox is for stuff you haven’t read
do
- or add to a to-do list or calendar

The Processing Habit

“We are what we frequently do.” – Aristotle

Do Email Less – once per hour for 10 minutes or less

Cheat

filtering
templates

No fiddling

East Coast Ethics

2007-09-19T19:22:11Z

As an Indiana resident and longtime fan of the Indianapolis Colts, it has been gratifying to watch the New England Patriots sweat while under investigation for taping the defensive coaches of the New York Jets.

Unfortunately, fans of the Patriots have been less than crestfallen at the ethical breech. This absence of outrage originates in a fundamental east coast world view that rewards cheating and laughs off ethical constraints.

To me, Belicheck and Patriots quarterback Brady are the embodiment of “east coast ethics.” For the average fan of the Patriots, Bill Belichick must be commended for taping the opposing sidelines – he would be a “sucker” if he didn’t push the envelope.

Brady, the playboy, impregnates supermodels at lightning speed, but can’t seem to figure out why deliberately breaking a written rule of the NFL might be considered cheating.

Since he can’t deal with adults but still finds success in his occupation, Belichick is called a genius. Instead of genius, he instead gets by on cheating and intimidation. Ask brain-damaged former Patriots linebacker Ted Johnson about Belichick’s commitment to his players. It ends the second you’re no longer useful to him. Belichick abstains from morality, in favor of expediency.

Picking up a well-known, team-splitting troublemaker like Randy Moss is no problem for the Patriots. As long as he produces on the field, his personality and his behavior are irrelevant. Adding one more spoiled apple to the oily, soulless bunch has no obvious effect.

The integrity-free exploits of Belichick and Brady stand in sharp contrast to the personas of Colts’ coach Tony Dungee and quarterback Peyton Manning. Regarded for their earnestness, ethics and work ethics, Dungee and Manning bring an old-school, midwestern personality to their team and to their state. That’s a personality that I can root for.

Dick Lugar: Hoosier Statesman

2007-09-19T17:37:28Z

I am consistently impressed, but never surprised, by the wisdom and leadership exhibited by Indiana’s senior senator, Dick Lugar. According to restore-habeas.org, he supports the Leahy-Specter-Dodd Amendment to restore habeas corpus. Between this stance and his recent “outside the party line” take on Iraq, it is a wonder the rest of the Republican senate even lets this guy in the clubhouse anymore.

Revered for his foreign policy acumen, Lugar should be commended for having the courage to step out of line and take on his own party, and put nation above partisanship on the real issues of the day.

At another level, though, Lugar is reflecting a state that is only solidly red in the eyes of national commentators on presidential election nights. Casual observers note Indiana’s track record of supporting Republicans in presidential races (LBJ was the last Democrat to collect our electoral college votes), but fail to note the generally-functional two party system that prevails in most of our other races.

Hoosiers routinely split the statehouse, abhorring the leadership vacuum that a one-party system inevitably creates.
After a pair of Democrats, our current Republican governor is thought to be in jeopardy in his bid for re-election.
Between Lugar and Evan Bayh, we’ve elected two senators who are moderates in the positive sense of the word, building consensus in Indiana and in Washington instead of exploiting easy class, social and political divisions.

Coming at the call of a moderate populace, the actions of Dick Lugar should be a source of pride for all of Indiana.

190 over 130 is bad?

2007-09-13T21:16:00Z

It turns out my experimental “Fast Food Only” diet of the past 5 years was not as well-designed as I had originally thought.

Wacky blood pressure. It turns out my experimental “Fast Food Only” diet of the past 5 years was not as well-designed as I had originally thought. Luckily I’ve ducked hospitalization twice. Nitroglycerin brings the blood pressure down out of the “imminent stroke” range and into the “prolonged suffering preceding the eventual stroke” range with just a raging migraine as the side-effect.

I’ve cut out a ton of sodium that I had been eating (OK, literally 2-3 grams per day) and I hope to be in the “might eventually be healthy” and then the “healthy” range soon. Hopefully last week was my “rock bottom” to be followed by a precipitous improvement.

Rove Heading Home? I don't buy it.

2007-08-14T05:03:00Z

Karl Rove said Monday that he would resign his position as a deputy White House chief of staff at the end of the month. I would love to accept this as good news, but until I see a house on top of him, I won’t believe the wicked witch is gone for good.

Isn’t this the perfect time to slither to a new campaign and weasel back into the ruling class for four more years? Be on the lookout for slime trails leading to New Hampshire, Iowa or South Carolina.

The Comcast Channel-Adder Guy

2007-07-08T01:50:00Z

Comcast channel-adder guy has been reading my mind again. I first noticed this phenomenon last summer during the world cup. The day before the first game was to be shown on ESPN2, we magically got ESPN2 in HD. That fall was the second instance, this time the local Fox affiliate’s HD hit our lineup, just in time for the first NFL broadcast of the season. Thanksgiving night, the CCAG struck again, sneaking the NFL Network’s HD feed over the top of a previously assigned HD channel in time for the first NFL-N regular season broadcast.

Today, he’s back, adding the Universal HD Channel in time for its coverage of the Live Earth concerts today. Allegiances can change, love can fade, but I always know that the Comcast channel-adder guy has my back.

South Bend Ruby Group Meeting

2007-05-30T13:46:00Z

Last night, John Nunemaker and I presented information we gleaned from RailsConf earlier this month in Portland, Oregon. Below are notes from my test-heavy track of RailsConf 2007 sessions, as presented to the SouthBend.rb ruby and rails user group on May 29, 2007.

Here’s a MacBook’s view of John’s Presentation.

Two crowd reaction shots are in my sbrb flickr set.

RailsConf 2007: Intro to TDD for Rails

2007-05-24T02:51:00Z

TDD and Refactoring, with a dash of Extreme Ping Pong…

Intro to Test-Driven Development for Rails – David Chelimsky

We all love to hack, deep in our holes. – David Chelimsky

Description

Test-Driven Development is a design and testing practice in which the developer writes the test before the code being tested. Practiced with discipline, TDD can lead to cleaner, more flexible designs that are implicitly testable and, consequently, more easily maintained over the lifetime of an application.

In this hands-on tutorial, we’ll go through the basics of TDD, beginning with a simple Ruby program and then moving onto a Rails application. This is intended for Rails developers of any level (but with at least some novice Ruby and Rails experience) who have little or no previous TDD experience.

Extreme Programming Practices

User Stories => expressing simple requirements from the perspective of a user in the system. forces developers and users to talk about the details during the development process (versus documenting the whole thing up front)
Customer Acceptance Tests
Test Driven Development
Pair Programming (increases the bus number)
Refactoring => change the structure of the code without changing the behavior of the code
- assumes you have the right tests and enough tests => not infallible

“Clean Code That Works” => The Goals of Test-Driven Development

What the hell was I thinking earlier today? - David Chelimsky

It’s cheaper to do something right than to do it over.
Will feel slower initially.

Any fool can write code that a computer can understand. Good programmers write code that humans can understand. - Martin Fowler

code should tell its own story
tests tell how the code fits together.

TDD Demo

Ping Pong => one programmer writes a failing test, the other programmer makes the test pass
what is the error and how do I make it go away?
test/unit ships with ruby => looks for method names starting with test, catalogs them and reinitializes the test class, creating a new instance for each method
assert asserts the existence of an object (nil makes it fail, 0 is an object, so it would pass)
try to have 1 assertion per method
“tell, don’t ask” => instead of asking an object for stuff, tell it to do stuff. results in more loosely coupled systems.
read fowler’s refactoring book
TDD is about design
don’t write any code except to make a test pass => sometimes seems counter-intuitive
code is a liability, not an asset
clarity is king in tests, not DRY
DRY is about objects, not typing
weigh duplication against clarity
setup comes from test/unit, runs before each method
good names are vital
reduces the number of up-front decisions you have to make. postponing decisions is a competitive advantage.
test collections for 0, 1 and 3
code dojos
rspec and bdd

TDD Cycle

write a small test (one assertion per test)
watch it fail (compilation errors count)
make the test pass doing the simplest thing that will possibly work
refactor to remove duplication
repeat

Refactoring

Improving the structure of code without changing its behavior

run all of the tests
- they all must pass
make a change
run all of the tests
- they all must pass

Must be green (passing all tests) before refactoring. Comment out a failing test to get green if you must.
Refactoring should never take you into the red (failing tests).

Mock Objects

mocha can do mock objects in test/unit; rspec has its own mock objects

RailsConf 2007: Testing Legacy Rails Applications

2007-05-23T20:27:00Z

Looking through my notes, I really made my own “Testing” track at RailsConf. Obviously the product of real-world experience, Rabble’s session on testing “legacy” rails apps was instructive, measured and to the point, laying out a step-by-step path to full test coverage.

Adding Tests to Legacy Rails Apps – Evan (Rabble) Henshaw-Plath

Description

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.

Ruby on Rails encourages regression testing in the framework by making it easy and creating the tests out of the box. Despite the encouragement, many Rails developers jumped ahead to the coding and left testing to languish for months or years untouched.

This talk will provide a pragmatic approach to adding testing to your existing Rails application. Built on real-world experience adding test coverage to large Rails applications. The talk will cover the benefits of adding incremental test coverage to an existing app and techniques for getting started on testing a legacy app.

Techniques for testing a legacy app:

Steps to adding tests
How to get on the path of writing and using tests
Using tests in deployment
Adjusting release cycles with expanded test coverage
Integrating testing in to the developer’s workflow

Tools for testing a legacy app:

Building tests from the logs
Evaluating test coverage using rake and rcov
Using zentest to build out tests quickly
Autotest for setting up cia and continuous_builder
RIG: Rails Integration Generator

Even a few tests with the right setup can help improve a project if they are integrated into, and run as part of, the development process. There is hope for the legacy Rails app without tests.

Do we have legacy apps already?

No, but we do have test-less apps.
Testing != Health Food
- Who has time for tests?
Testing == Debugging

Starting

Don’t do it all at once. It won’t work.
first, run rake
- mysqladmin -u root create chq2_test
Use Migrations
Scaffolding is broken => those tests don’t work.

Now, let’s get going. One step at a time, literally:

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 testing: rake test:uncommitted
direct: -n test_name to run one test in a file

build tests from logs

parameters => reproduce actual requests

what to test:

right response code
correct template
variable assignment
assignment of desired object

test coverage

rcov test coverage => what needs to be tested

autotest

sometimes our tests can run themselves
continuous integration only runs when you check-in

fixtures == ugliness

ar_fixtures
use mocks
fixture scenarios

RailsConf 2007 Sessions: Clean Code

2007-05-23T19:41:00Z

Robert Martin’s session on clean code has already reshaped my development practices. Bob provided an excellent overview of the use of Test-First practices and nailed down many of the gaps in my understanding. His demonstration of TDD without making breaking changes was especially interesting, serving to affirm the mantra “I am not allowed to make a change that breaks the system.”

Clean Code – Robert Martin, Object Mentor

Description: Ward Cunningham once said that Smalltalk failed because it was too easy to make a mess. Professionals don’t make messes. This talk demonstrates the techniques and heuristics for keeping Ruby code clean and stresses the attitude of professionalism and craftsmanship that can keep Ruby from Smalltalk’s fate.

What are we going to do about bad code?

The grand redesign in the sky
- 10 years to develop the new system
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
understand the open closed principle => open for extension, closed for modification
Time to refactor => things are about to get smelly.
started out clean,
- built up over time
- initial structure didn’t scale well
- the more it grew the worse it got
- eventually I had to stop
iterating is where its at

TDD => Keep the system running at all times!

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
meta-programming to build marshallers only when you need them
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
bad code rots ferments and becomes an inexorable weight that drags the team down.

Professional Behavior

The “Green Band” on his wrist that says “Test Obsessed”
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

Contact

Fitnesse

RailsConf 2007: Doing REST Right

2007-05-23T18:39:00Z

Scott Raymond’s “Doing REST Right” session was a highlight for me at the just-concluded RailsConf. An experienced creator of REST-based solutions, Raymond shared an overview of REST, outside the context of rails, and an invaluable FAQ. Here are my notes from that session.

Doing REST Right – Scott Raymond, Firewheel Design

Description: Rails helps developers build REST-style web services in many ways, but important design decisions remain for each application. In this talk, we’ll go beyond the basics and tackle the practical questions that arise when implementing a modern web service in Rails.

Come unto me, all ye that labour and are heavy laden, and I will give you REST – God

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

http crud sql

post create insert

get retrieve select

put update update

delete destroy delete

tools for organizing your application code
- respond_to
- map.resources

http
a protocol
an architecture

REST is…

the architectural style of the web

Roy Fielding’s Hierarchy

Abstract Communication Theory

— REST

— Web Architecture

Concrete Implementation

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 (Address)
- My name is URL.
Interaction (Method or Verb) – the uniform interface, uniform small set of methods
- 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 is neither safe nor idempotent => reserve it for when you need it
Content (Data, Body of Request)
- REST pushes all of the complexity into content, out of identification and interaction
- standards
  - messages should 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

Questions in SCO’s Experience

How do I update several resources at once? Like a to-do list application with a bunch of “finished” checkboxes…
- Scope this request to a set of resources, using the URL
- create a url that names that superset, then update them all (one resource) with one request

How can I do partial updates? Like a person resource, changing just the name…
- Scope in the url => give names a url (“people/5/name”), then post to that resource

I’m special; I need more than GET/POST/PUT/DELETE semantics.
- You’re wrong. You can model any problem in REST. The uniform interface is sufficiently general.

How should I do authentication?
- cookies force application state into the server
- how about HTTP Basic? Makes each request self sufficient. Guards against restart, but UI sucks. Password is in cleartext with every request.
- HTTP-Digest => eh, not quite.
- use cookies, but make each request self-sufficient with its own session information

Should I include content-type info in the URL?
- Opinions have changed over the past year.
- Previously => No, and you get network effects. But you can’t link to a specific representation, only the default representation.
- URLs are UI, don’t let rails force your hand.
- Now => Yes. gets you better page caching.

What about reliability?
- with posts, you divide them into 2 phases
  - Post to a factory method that creates a new url
  - Post (commit) to that fancy url.

What about concurrency?
- Use entity tags

What about transactions?
- Still a scope question => make a new URL that represents the full transaction.

I need more than one representation with the same media type.
- avoid using a generic media type, make your own

http	crud	sql
post	create	insert
get	retrieve	select
put	update	update
delete	destroy	delete

Abstract	Communication Theory
—	REST
—	Web Architecture
Concrete	Implementation