Three handy Ruby gems inspired by the same project at Lonely Planet.

1. One project,
three gems
Mike Williams
Cogent Consulting
in association with

2. Architecture
“Atlas”
<stuff/>

3. arboreal
Growing Trees
(restaurant)
(hotel)
Melbourne
Sydney
Geelong
Victoria NSW (sight)
WA Australia
New Zealand
Pacific
Europe
Asia
WORLD
Americas Africa

4. arboreal
how do I select this?
Melbourne
Sydney
Geelong
Victoria NSW
WA Australia
New Zealand
Pacific
Europe
Asia
WORLD
Americas Africa

5. arboreal
Path Enumeration
@victoria = Place.find_by_name(“Victoria”)
@victoria.ancestry_string
#=> “-4-14-15-”
Melbourne
Sydney
Geelong
Victoria NSW
Australia 15
WA
New Zealand
Pacific 14
Europe
WORLD 4
Asia
Americas Africa

6. arboreal
@victoria.ancestors
SELECT * FROM places WHERE (id in (4,14,15))
Melbourne
Sydney
Geelong
Victoria NSW
Australia 15
WA
New Zealand
Pacific 14
Europe
WORLD 4
Asia
Americas Africa

7. arboreal
@australia = Place.find_by_name(“Australia”)
@australia.children
SELECT * FROM places WHERE (places.parent_id = 15)
Melbourne
Sydney
Geelong
Victoria NSW
Australia 15
WA
New Zealand
Pacific
Europe
Asia
WORLD
Americas Africa

8. arboreal
@australia.descendants
SELECT * FROM places
WHERE (places.ancestry_string like ‘-4-14-15-%’)
“-4-14-15-22-”
Melbourne
Sydney “-4-14-15-16-”
Geelong
Victoria NSW
“-4-14-15-”
WA Australia
New Zealand
Pacific
Europe
Asia
WORLD
Americas Africa

9. arboreal
@australia.subtree
SELECT * FROM places
WHERE (places.id = 15 OR places.ancestry_string like ‘-4-14-15-%’)
“-4-14-15-22-”
Melbourne
Sydney “-4-14-15-16-”
Geelong
Victoria NSW
“-4-14-15-”
Australia 15
WA
New Zealand
Pacific
Europe
Asia
WORLD
Americas Africa

10. arboreal
@australia.subtree.scope(:find, :conditions)
#=> [“places.id = ? OR places.ancestry_string like ?”, 15, “-4-14-15-%”]
class Place
def contained_pois
Poi.scoped(:include => :place,
:conditions => subtree.scope(:find, :conditions))
end
end
@australia.contained_pois
SELECT ... FROM pois
LEFT OUTER JOIN places ON places.id = pois.place_id
WHERE (places.id = 15 OR places.ancestry_string like ‘-4-14-15-%’)

11. arboreal
@australia.contained_pois
SELECT ... FROM pois
LEFT OUTER JOIN places ON places.id = pois.place_id
WHERE (places.id = 15 OR places.ancestry_string like ‘-4-14-15-%’)
Melbourne
Sydney
Geelong
Victoria NSW
WA Australia
New Zealand
Pacific
Europe
Asia
WORLD
Americas Africa

12. GET http://stuff.local/places/15/pois
“Atlas”
<pois/>

13. <pois type="array">
<poi>
<created-at type="datetime">2010-08-25T23:35:59Z</created-at>
<email nil="true"></email>
<id type="integer">6</id>
<latitude type="decimal">-37.8002389992226</latitude>
<longitude type="decimal">144.901535511017</longitude>
<name>Footscray Market</name>
<place-id type="integer">26</place-id>
<review>A frenetic covered food market.</review>
<type>See</type>
<updated-at type="datetime">2010-08-25T23:35:59Z</updated-at>
<url nil="true"></url>
</poi>
<poi>
<created-at type="datetime">2010-08-25T23:35:59Z</created-at>
<email nil="true"></email>
<id type="integer">7</id>
<latitude type="decimal">-37.8020224141169</latitude>
<longitude type="decimal">144.983611106873</longitude>
<name>Panama Dining Room</name>
<place-id type="integer">26</place-id>
<review>Franco-Fitzroy pub grub and ersatz Manhattan views.</review>
<type>Eat</type>
<updated-at type="datetime">2010-08-25T23:35:59Z</updated-at>
<url nil="true"></url>
</poi>
...

14. <pois type="array">
<poi href="http://stuff.local/pois/6">
<name>Footscray Market</name>
<type>See</type>
<review>A frenetic covered food market.</review>
<place href="http://stuff.local/places/26">
<name>Melbourne</name>
</place>
</poi>
<poi href="http://stuff.local/pois/7">
<name>Panama Dining Room</name>
<type>Eat</type>
<review>Franco-Fitzroy pub grub and ersatz Manhattan views.</review>
<place href="http://stuff.local/places/26">
<name>Melbourne</name>
</place>
</poi>
<poi href="http://stuff.local/pois/8">
<name>Sydney Opera House</name>
<type>See</type>
<review/>
<place href="http://stuff.local/places/17">
<name>Sydney</name>
</place>
</poi>
</pois>

15. # BEFORE ...
xml.pois :type => “array” do
@pois.each do |poi|
xml.poi :href => poi_url(poi) do
xml.name(poi.name)
xml.type(poi.type)
xml.review(poi.review)
xml.place :href => place_url(poi.place) do
xml.name poi.place.name
end
end
end
end

16. # BEFORE ... representative
xml.pois :type => “array” do
@pois.each do |poi|
xml.poi :href => poi_url(poi) do
xml.name(poi.name)
xml.type(poi.type)
xml.review(poi.review)
xml.place :href => place_url(poi.place) do
xml.name poi.place.name
end
end
end
end
# AFTER ...
Representative::Xml.new(xml) do |r|
r.list_of :pois, @pois, :item_attributes => {:href => method(:poi_url)} do
r.element :name
r.element :type
r.element :review
r.element :place, :href => method(:place_url) do
r.element :name
end
end
end

17. # XML ... representative
Representative::Xml.new(xml) do |r|
r.list_of :pois, @pois, :item_attributes => {:href => method(:poi_url)} do
r.element :name
r.element :type
r.element :review
r.element :place, :href => method(:place_url) do
r.element :name
end
end
end
# JSON ...
Representative::Json.new do |r|
r.list_of :pois, @pois, :item_attributes => {:href => method(:poi_url)} do
r.element :name
r.element :type
r.element :review
r.element :place, :href => method(:place_url) do
r.element :name
end
end
end.to_s

18. <pois type="array">
<poi href="http://stuff.local/pois/6">
<name>Footscray Market</name>
<type>See</type>
<review>A frenetic covered food market.</review>
<place href="http://stuff.local/places/26">
<name>Melbourne</name>
</place>
</poi>
<poi href="http://stuff.local/pois/7">
<name>Panama Dining Room</name>
<type>Eat</type>
<review>Franco-Fitzroy pub grub and ersatz Manhattan views.</review>
<place href="http://stuff.local/places/26">
<name>Melbourne</name>
</place>
</poi>
<poi href="http://stuff.local/pois/8">
<name>Sydney Opera House</name>
<type>See</type>
<review/>
<place href="http://stuff.local/places/17">
<name>Sydney</name>
</place>
</poi>
</pois>

19. representative
[
{
"name": "Footscray Market",
"type": "See",
"review": "A frenetic covered food market.",
"place": {
"name": "Melbourne"
}
},
{
"name": "Panama Dining Room",
"type": "Eat",
"review": "Franco-Fitzroy pub grub and ersatz Manhattan views.",
"place": {
"name": "Melbourne"
}
},
{
"name": "Sydney Opera House",
"type": "See",
"review": null,
"place": {
"name": "Sydney"
}
}
]

20. “Atlas”
<pois/>

21. <pois/> something
that wants
POI data

22. <pois/> something
fake
that wants
Atlas
POI data

23. sham
rack
require ‘fakeweb’
FakeWeb.register_uri(:get, “http://www.example.com/hello”, :body => “Hello World!”)
require ‘webmock’
stub_request(:get, “www.example.com/hello”).to_return(:body => “Hello, World!”)
require ‘sham_rack’
ShamRack.at(“www.example.com”).stub.register_resource(“/hello”, “Hello, World!”)

24. sham
rack
It’s just Rack!
client Net::HTTP
Sham Rack
Rack app

25. sham
rack
It’s just Rack!
ShamRack.at("www.example.com”) do |env|
[
"200 OK",
{ "Content-type" => "text/plain" },
"Hello, world!"
]
end
ShamRack.at("www.example.com").rackup do
use Some::Middleware
use Some::Other::Middleware
run MyApp.new
end

26. sham
rack
It’s just Rack!
ShamRack.at("www.example.com").sinatra do
get "/hello/:subject" do
"Hello, #{params[:subject]}"
end
end

27. http://github.com/mdub/arboreal
http://github.com/mdub/representative
http://github.com/mdub/sham_rack