Erector Cache¶ ↑

Widget caching for Erector.

Note: This only works at the widget level as this is essentially a fragment caching utility, and will not work for widgets rendered directly from a controller. (widget vs render_widget)

Installation¶ ↑

sudo gem install erector_cache

Checkout redis github.com/antirez/redis and install

MAKE SURE REDIS SERVER IS RUNNING

First, connect to the Redis database. This would most likely go into an environment.rb.

Lawnchair.connectdb

This will connect to a default database on localhost, if you want to connect to a particular database you can do:

Lawnchair.connectdb(Redis.new(:database => 11, :host => "127.0.0.1", :port => 6379))

Usage¶ ↑

• cache_for - Use this to tell the widget how long it should be cached for. Defaults to 1 hour

• cache_with - These are the widget parameters you want to use to build the cache key

• expire! - Expire the instances of a widget matching the given parameters

  class Bluth < Erector::Widget
    cache_with :name, :mistake
    cache_for 3.seasons
  
    def content
      div "My name is #{@name} and #{@mistake.to_param}"
    end
  end
  
  class Mistake < ORM::Base
    attr_reader :updated_at
  
    def initialize(size)
      @size = size || :huge
      @updated_at = Time.now
    end
  
    def size
      @size
    end
  
    def to_param
      "I_just_made_a_#{size}_mistake"
    end
  end
  

cache_with¶ ↑

In the simple case the cache key will be built off of the value of the parameter eg.

widget Bluth, :name => "George Michael", :mistake => "consubrinaphilia"

This will yield a cache key of “Lawnchair:Bluth:name:GeorgeMichael:mistake:consubrinaphilia”

---

You can also pass whole objects into the widget and build the cache based on this. It will default to using the to_param of the object as the key component value.

@mistake = Mistake.create(:huge)
widget Bluth, :name => "Gob", :mistake => @mistake

This will yield a cache key of “Lawnchair:Bluth:name:Gob:mistake:I_just_made_a_huge_mistake”

---

This is essentially the same as doing this, which opens up more complex possibilities for generating cache keys

class Bluth < Erector::Widget
  cache_with :name, :mistake => lambda {|mistake| mistake.to_param }
end

@mistake = Mistake.create(:huge)
widget Bluth, :name => "Gob", :mistake => @mistake

---

Using this, we could set the cache to auto expire every time the associated object is updated.

class Bluth < Erector::Widget
  cache_with :name, :mistake => lambda {|mistake| mistake.updated_at }
end

Expiration¶ ↑

Widget expiration is possible by calling the widget class’s expire! method and passing in as much information about the keys to expire as you want.

Assume the following have occurred:

widget Bluth, :name => "Tobias", :mistake => "I_just_blue_myself"
widget Bluth, :name => "Tobias", :mistake => "analyst_and_therapist"
widget Bluth, :name => "Buster", :mistake => "swimming_with_seal"

You can expire all Bluth widgets regardless of what the values of the params passed into them with:

Bluth.expire!

You can expire only the Bluth widget with :mistake => “I_just_blue_myself” by using:

Bluth.expire!(:mistake => "I_just_blue_myself")

You can expire all widgets with :name => “Tobias” with:

Bluth.expire!(:name => "Tobias")

Likewise, calling the following will expire only the one cached version of the widget that exists, leaving the other instance in the cache:

Bluth.expire!(:name => "Tobias", :mistake => "I_just_blue_myself")

Any cache key component that is not passed into the expire! method will result in a wildcard match on that component, allowing you to be as specific as you wish.

Note: Lawnchair will automatically condense spaces, so don’t feel constrained to using underscores or dashes in keys.

                        ....:~~~~~~~~~~~~~:~~::::::,..                         
                  ......,~===~=====~~~~~::::::::::::::,.....  ..               
                  ....,~+++=++++++==~~~~:::::::::::::::,...  ..                
                  ..~I?+?????+?+++===~~~~::::::::::::::~:,...   .              
                  .=I7?I?????+?+++===~~~~~:::::::::::::~~:....  ..             
            .....~$$77II7III?+?++++===~~~~::::::::::::::~~=:......             
            ....:ZZ$$7IIIIII???++++++==~~~:::::::::~~~:~~~==,.....             
            ....7OZZ$77I777I????+++++==~~::::::::::~~::~~~===, ..              
            ...?OOOZ$$$7777II?????+++===~~:::::::::::::~~~~==~....             
            ..,7OOO$$$$$7777II??+++==~~~~~::::::::::::~::::~~=,...             
            . ?OOOOZZ$$$77777I??++=++=~~~~:::::::::::::::~~===:...             
            ..I8OOO$Z$ZZ77777I???+=+==~~::::::::::,:::::~=+++++...             
             ,78OOO$ZZZ$$7777II7ZOOOOZ$7?+~~::::,,,::~~~?I7ZOOZ?..... ..       
             ,7O8OO$$ZZZ$77$77ZOO8OOZ$II?+++=::,,,:::~===~+++I$Z:.... ..       
             :7O88O8Z$$$$$$$OOZ???+III777$?+=~~::::::~:=I7+=::~+:~~, ..        
             ,7OOO8OOZ77$I$OZIII~~~~=+???++I7I=:~=~=+I$=~I~=~:~+...=,:,        
            ..IOOO8OOZ777IZZ+=I++++?+=??I7II7$Z$??I$$$+?+=::~~=:.. ,=?:        
            ..?O88O88OZ$$$$7$Z+?+?77ZOO7III$7$ZI=:::Z7+78ZO8$I~=~++,~=..       
            ..+O88O8OOZ$777=$7=??$ODN$8?+$I?7787=~~:O$?ZN88$Z8?=~...+:..       
            ,:+7ZDDD8OZZ$$7?$Z?IZOII$7?++++?77$??+~:IZ=?+~~=+II=,...+,.        
      .....:II++7O8DOZ$$7$7IIZ??7Z7?~~=+++=+7O7+I?=:+$~=?7I??I?+:..:+..        
      ... .?ZOZ?++$8O$$7777??7$=???I?+===~:~77+I?==~:~=~~~~~~~~==.,:..         
      ... ,+77?7OI78O777777II+?$=~~~~~~~:::II+$7?+~:~:~~~:,:::::~=:.....       
      ....,+77==Z$$8O$7777IIII??I=:::::,,+?II?77I+~,,::=I7~,,.:=++:....        
      .....=7?=?O8$88Z$$$777II?+=+7$IIII=:+$7III77?==~~=+=+?+=~~~~:.....       
      .....~7++7877O8O$$$$77I?+===:~~:::~+IZ$I?+7O$+=~~?++==~::::~:....        
      .....,I+?==?788OZZ$$77II?+==~~~~~===+7ODD8OZ8OZZ8D7+~~++~~~=: ...        
      ......I=+=+I7O8OOZZ$777I??+===~~====+?IOO$7$O88Z$$7+=~=+=~==:.....       
            ,$++7ZIOD8OZ$$$7777I?++=====?I$ZZZ$Z77ZZOOZ$ZZ$I+~+++=.....        
             ~I++?7OO$$$$$$777$77?++=?IZOZOOOOZZOOOOOOZ$ZOZ$Z$+=+~......       
            .,?++?IZO$$Z$$$777777I??I$ZOOOOOOOZZOZZ7II$7IZOOOZI=+~......       
            ..,II=:?Z$$$$$$77I77I?78888888OZZZ$77$III7?+?$O8OO$++,..  .        
            ...,,..,7$$$$$$77I7777O8O8D888OZ?II:===?=,:.?NNOZO7++,..           
            ........?7$$$$$77II77II=+77Z8NNNNDNNN8DNDNMNO7+?7I++~.    .        
            ........?$$$$$$$7I777I?==+++?IO8OZI==,::,?$7I?==?+==:              
               .....?7$$$$Z$77I7$$7?=++++I??7I+===+?+=?I?===~=+=..             
                  ..?$$ZZZZ$$$77777I?+=+++II++++=====++===~~==+...             
                  . ?$$$ZZZZ$$777777I+=+++?II?+????++?+++=~~==~...             
            .  .  ..I$$ZZOOOZZ$$777777+=+?+=+?++++==+=~~~~~~~~...              
            .......:$$ZZZOOOOOZZ$777$$?+=+++===~~=~~~~~~~~~~=, ..              
             .....,I$7$$$$$ZOOOOZ$$7$Z7I+=====~~:::~:~~~~~=~.....              
            . ....+77777$$$ZOO88OZZ$$Z$I?+=====~~::~~~~~=~=,.. ..              
 . .,,    ......,I77$$7I7777$$ZO888OOZOO$I?+++==~::~~:~=~+~ . . ..             
. :D88DDDZ7+:.,?7I7$$$7IIIII777$ZOOO888OOZ$II??+====+==++,.                    
..?8Z8O88DDDDO7I??777IIIII?77I7$$ZOOOOOOOOZ$$7I?+===+???,..                    
,Z8OOOOOO888888DD8DDD88DDD$?IIII7$ZOZOOOOOOOOZZZZZ$Z$I=.....

Copyright¶ ↑

Copyright © 2010 Grockit. See LICENSE for details.