Class: Queris::HashCache

Inherits:
Index
  • Object
show all
Defined in:
lib/queris/indices.rb

Constant Summary

Constants inherited from Index

Index::DELTA_TTL

Instance Attribute Summary

Attributes inherited from Index

#attribute, #delta_ttl, #live, #model, #name, #redis

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Index

#digest, #distribution, #eliminate, #erase!, #exists?, #handle_range?, #incremental?, #index_val, #json_redis_dump, #key_attr, #keypattern, #keys, #live_delta_key, #no_live_update, #poke, #skip_create?, #skip_delete?, #skip_update?, #stateless?, #temp_keys, #update_live_delta, #usable_as_results?, #val, #value_diff, #value_is, #value_was

Constructor Details

#initialize(arg = {}) ⇒ HashCache

maintains a cached copy of an object with separetely marshaled attributes in redis

Raises:



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# File 'lib/queris/indices.rb', line 195

def initialize(arg={})
  @name= "#{arg[:attribute] || "all_attribute"}_hashcache"
  super arg
  @attribute= arg[:attribute]
  raise ClientError, "Model not passed to index." unless @model
  @name=@model.to_s #whatever, name's not important.
end

Class Method Details

.skip_create? ⇒ Boolean

don’t add this index to the list of indices to be built when calling Queris.rebuild!

Returns:

  • (Boolean) 


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# File 'lib/queris/indices.rb', line 204

def self.skip_create?; true; end

Instance Method Details

#create(obj) ⇒ Object 



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# File 'lib/queris/indices.rb', line 223

def create(obj)
  if @attriute.nil?
    cache_attributes obj, obj.all_cacheable_attributes
  elsif not obj.call(@attribute).nil?
    cache_attributes obj, @attribute => send(@attribute)
  end
  
end

#delete(obj) ⇒ Object 



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# File 'lib/queris/indices.rb', line 232

def delete(obj)
  redis(obj).del hash_key obj
end

#fetch(id, opt = {}) ⇒ Object Also known as: load 



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# File 'lib/queris/indices.rb', line 236

def fetch(id, opt={})
  if @attribute.nil?
    hash = (opt[:redis] || Queris.redis(:slave, :master)).hgetall hash_key id

    loaded = load_cached hash
    if hash && loaded.nil? #cache data invalid. delete.
      Queris.redis(:master).del(hash_key id)
    end
    loaded
  else
    return (opt[:redis] || Queris.redis(:slave, :master)).hget hash_key(id), @attribute
  end
end

#hash_key(obj, prefix = nil, raw_val = false) ⇒ Object Also known as: key 



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# File 'lib/queris/indices.rb', line 206

def hash_key(obj, prefix=nil, raw_val=false)
  if raw_val
    id = obj
  else
    id = obj.kind_of?(@model) ? obj.send(@key) : obj
  end
  (@keyf) %[prefix || @redis_prefix || @model.prefix, id]
end

#info ⇒ Object 



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# File 'lib/queris/indices.rb', line 276

def info
  keycounts = distribution.values
  "HashCache: #{keycounts.count} objects cached."
end

#load_cached(marshaled_hash) ⇒ Object 



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# File 'lib/queris/indices.rb', line 250

def load_cached(marshaled_hash)
  @cached_attr_count ||= (not @attribute.nil?) ? 1 : @model.new.all_cacheable_attributes.length #this line could be a problem if more cacheable attributes are added after the first fetch.
  if marshaled_hash.length >= @cached_attr_count
    unmarshaled = {}
    marshaled_hash.each_with_index do |v|
      unmarshaled[v.first.to_sym]=Marshal.load v.last
    end
    obj= @model.new
    begin
      obj.assign_attributes(unmarshaled, :without_protection => true)
    rescue Exception => e
      #cache load failed because the data was invalid.
      return nil
    end
    obj.instance_eval do
      @new_record= false 
      @changed_attributes={}
    end
    obj
  else
    nil
  end
end

#update(obj) ⇒ Object 



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# File 'lib/queris/indices.rb', line 215

def update(obj)
  changed_attrs = obj.changed_cacheable_attributes
  if @attribute.nil?
    cache_attributes obj, changed_attrs unless changed_attrs.length == 0
  elsif changed_attrs.member? @attribute
    cache_attributes obj, @attribute => send(@attribute)
  end
end