Liquid Markup

Talk I gave October 4, 2012 at Pittsburgh Ruby Brigade.

Transcript

1. Liquid Markup
2. Jon Daniel @binarycleric github.com/binarycleric
3. Obligatory Promotion We’re Hiring Smart People. Ruby experience NOT required.
4. What Is Liquid?
6. github.com/Shopify/liquid
7. lets clients design their own sites...
8. safely and securely
9. logic and variable manipulation
11. yay!
13. $ gem install liquid require 'liquid'
14. markup = "Hello, {{ thing }}!" t = Liquid::Template.parse(markup) t.render("thing" => "world")
15. Hello, world!
16. markup = "Welcome, {{ user.name }}" user = User.find(1337) t = Liquid::Template.parse(markup) t.render('user' => user)
17. Welcome, !
18. Liquid Has Trust Issues
19. Deny By Default
20. class Person < ActiveRecord::Base end # denied! "{{ person.name }}" => "" class Person < ActiveRecord::Base liquid_methods :name end # okay! "{{ person.name }}" => "Cmdr Shepard"
21. markup = "Welcome, {{ user.name }}" user = User.find(1337) t = Liquid::Template.parse(markup) t.render('user' => user)
22. Welcome, Jon ‘maddog’ Hall! * If you don’t know who he is, check Wikipedia.
23. Live Free Or Die.
24. Actually Rendering Templates
25. # load the user from somewhere. t = Liquid::Template.parse(markup) t.render("user" => user)
26. t = Liquid::Template.parse(markup) context = Liquid::Context.new(*args) t.render(context)
27. The Magic Context
28. Liquid::Context.new local_assigns, global_assigns, registers
29. Liquid::Context.new local_assigns, global_assigns, registers
30. registers[:domain] = domain registers[:whatever] = whatever registers[:your] = your registers[:app] = app registers[:needs] = needs registers[:file_system] = FileSystem.new
31. registers[:domain] = domain registers[:whatever] = whatever registers[:your] = your registers[:app] = app registers[:needs] = needs registers[:file_system] = FileSystem.new
32. Some Liquid Syntax
33. class FileSystem def initialize(*args) # whatever end def read_template_file(name, context) # fetches partials from wherever end end {% include 'some-partial' %}
34. # a block {% if liquid == 'awesome' %} You should try Liquid! {% endif %} # a tag {% assign liquid = 'awesome' %}
35. class ExampleTag < Liquid::Tag def initialize(name, markup, tokens) # setup the tag, parse stuff, ya know... # expensive stuff. end def render(context) # drop in the assigns and go! # should be cheap. end end
36. class ExampleTag < Liquid::Tag def initialize(name, markup, tokens) # setup the tag, parse stuff, ya know... # expensive stuff. end def render(context) # drop in the assigns and go! # should be cheap. end end
37. class PersonDrop < Liquid::Drop def addresses # stupid slow operation Address::find_by_person(@person) end end {{ user.addresses }}
38. {{ “hello world” | capitalize }} # shamelessly stolen from # liquid's source. use your # imagination people! def capitalize(input) input.to_s.capitalize end
39. Liquid Philosophies
40. •assume hostile environment •white list what you need •deny everything else
41. •can edit markup •is probably non-technical Assume the client
42. •ignore errors by default •don’t let the client break too much
43. It May Not Be For You
44. •partial branding •full white-label •per-install customization
45. Views As Data
46. Contribute!
47. Questions?