Class: Medea::JasonObject

Inherits:
JasonBase show all
Extended by:
ActiveModel::Naming
Includes:
JasonObjectMetaProperties, ActiveModelMethods
Defined in:
lib/medea/jasonobject.rb

Constant Summary

Constants inherited from JasonBase

Medea::JasonBase::HTTP_VERBS

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from JasonObjectMetaProperties

included

Methods included from ActiveModelMethods

#errors, #persisted?, #to_model, #valid?

Methods inherited from JasonBase

#==, #add_public, #build_url, #delete!, #get_public, #jason_etag, #jason_key, #jason_parent, #jason_parent=, #jason_parent_key, #jason_parent_key=, #jason_parent_list, #jason_parent_list=, #jason_state, #jason_timestamp, #load_from_jasondb, #permissions_header, #remove_public, resolve, #set_public

Methods included from ClassLevelInheritableAttributes

included

Constructor Details

#initialize(initialiser = nil, mode = :eager) ⇒ JasonObject

Returns a new instance of JasonObject.



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# File 'lib/medea/jasonobject.rb', line 113

def initialize initialiser = nil, mode = :eager
  @attachments = {}
  if opts[:attachments]
    opts[:attachments].each do |k|
      @attachments[k] = nil
    end
  end

  @public = []
  if opts[:public]
    opts[:public].each {|i| @public << i}
  end

  if initialiser
    if initialiser.is_a? Hash
      @__jason_state = :new
      @__jason_data = sanitize initialiser
    else
      @__id = initialiser
      if mode == :eager
        load_from_jasondb
      else
        @__jason_state = :ghost
      end
    end
  else
    @__jason_state = :new
    @__jason_data = {}
  end
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(name, *args, &block) ⇒ Object

The “Magic” component of candy (github.com/SFEley/candy), repurposed to make this a “weak object” that can take any attribute. Assigning any attribute will add it to the object’s hash (and then be POSTed to JasonDB on the next save)



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# File 'lib/medea/jasonobject.rb', line 87

def method_missing(name, *args, &block)
    load_from_jasondb if @__jason_state == :ghost
    field = name.to_s
    if field =~ /(.*)=$/  # We're assigning
        self[$1] = args[0]
    elsif field =~ /(.*)\?$/  # We're asking
        (self[$1] ? true : false)
    else
        self[field]
    end
end

Instance Attribute Details

#attachments ⇒ Object

Returns the value of attribute attachments.



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# File 'lib/medea/jasonobject.rb', line 16

def attachments
  @attachments
end

Class Method Details

.all(opts = nil) ⇒ Object

create a JasonDeferredQuery for all records of this class & with some optional conditions



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# File 'lib/medea/jasonobject.rb', line 22

def JasonObject.all(opts=nil)
  q = JasonDeferredQuery.new :class => self, :filters => {:VERSION0 => nil, :FILTER => {:HTTP_X_CLASS => self, :HTTP_X_ACTION => :POST}}
  if opts
    q.limit = opts[:limit] if opts[:limit]
    q.since = opts[:since] if opts[:since]          
  end

  q
end

.get_by_key(key, mode = :eager) ⇒ Object

returns the JasonObject by directly querying the URL if mode is :lazy, we return a GHOST, if mode is :eager, we return a STALE JasonObject



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# File 'lib/medea/jasonobject.rb', line 56

def self.get_by_key(key, mode=:eager)
  return self.new key, mode
end

.method_missing(name, *args, &block) ⇒ Object

here we will capture: members_of(object) (where object is an instance of a class that this class can be a member of) find_by_<property>(value) Will return a JasonDeferredQuery for this class with the appropriate data filter set



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# File 'lib/medea/jasonobject.rb', line 36

def JasonObject.method_missing(name, *args, &block)

  q = all
  if name.to_s =~ /^members_of$/
    #use the type and key of the first arg (being a JasonObject)
    return q.members_of args[0]
  elsif name.to_s =~ /^find_by_(.*)$/
    #use the property name from the name variable, and the value from the first arg
    q.add_data_filter $1, args[0]

    return q
  else
    #no method!
    super
  end
end

Instance Method Details

#[](key) ⇒ Object 



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# File 'lib/medea/jasonobject.rb', line 72

def [](key)
  if @attachments.keys.include? key.to_sym
    if not @attachments[key.to_sym]
      #retrieve the JasonBlob for this key
      @attachments[key.to_sym] = Medea::JasonBlob.new({:parent => self, :name => key})
    end

    return @attachments[key.to_sym]
  end
  @__jason_data[key]
end

#[]=(key, value) ⇒ Object

“flexihash” access interface



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# File 'lib/medea/jasonobject.rb', line 61

def []=(key, value)
  if @attachments.keys.include? key.to_sym
    @attachments[key.to_sym] = Medea::JasonBlob.new({:parent => self, :name => key, :content => value})
    return
  end
  @__jason_data ||= {}
  @__jason_state = :dirty if jason_state == :stale

  @__jason_data[key] = value
end

#persist_changes(method = :post) ⇒ Object 



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# File 'lib/medea/jasonobject.rb', line 200

def persist_changes method = :post
  payload = self.serialise

  post_headers = {
      :content_type => 'application/json',
      "X-KEY"       => self.jason_key,
      "X-CLASS"     => self.class.name
      #also want to add the eTag here!
      #may also want to add any other indexable fields that the user specifies?
  }
  post_headers["IF-MATCH"] = @__jason_etag if @__jason_state == :dirty

  post_headers["X-PARENT"] = self.jason_parent.jason_key if self.jason_parent
  post_headers["X-LIST"] = self.jason_parent_list if self.jason_parent_list

  if opts[:located]
    #set the location headers
    if geohash?
      post_headers["X-GEOHASH"] = geohash
    end
    if latitude? && longitude?
      post_headers["X-LATITUDE"] = latitude
      post_headers["X-LONGITUDE"] = longitude
    end
  end

  post_headers.merge! permissions_header

  url = to_url()

  #puts "Saving to #{url}"
  if method == :post
    response = RestClient.post(url, payload, post_headers)
  elsif method == :delete
    response = RestClient.delete(url, post_headers)
  else
    raise "Unknown method '#{method.to_s}'"
  end

  if response.code == 201
    #save successful!
    #store the new eTag for this object
    #puts response.raw_headers
    @__jason_etag = response.headers[:Etag]
    @__jason_timestamp = response.headers[:timestamp]
  else
    raise "#{method.to_s.upcase} failed! Could not persist changes"
  end

  @__jason_state = :stale
end

#sanitize(hash) ⇒ Object

end “flexihash” access



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# File 'lib/medea/jasonobject.rb', line 100

def sanitize hash
  #remove the keys in hash that aren't allowed
  forbidden_keys = ["jason_key",
                    "jason_state",
                    "jason_parent",
                    "jason_parent_key",
                    "jason_parent_list"]
  hash.delete_if { |k,v| forbidden_keys.include? k }
  result = {}
  hash.each { |k, v| result[k.to_s] = v }
  result
end

#save ⇒ Object

POSTs the current values of this object back to JasonDB on successful post, sets state to STALE and updates eTag



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# File 'lib/medea/jasonobject.rb', line 163

def save
  return false if @__jason_state == :stale or @__jason_state == :ghost
  begin
    save!
    return true
  rescue
    return false
  end
end

#save! ⇒ Object 



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# File 'lib/medea/jasonobject.rb', line 173

def save!
    @attachments.each do |k, v|
      if v
        v.save!
      end
    end

    #no changes? no save!
    return if @__jason_state == :stale or @__jason_state == :ghost

    #validations
    if self.class.owned
      #the parent object needs to be defined!
      raise "#{self.class.name} cannot be saved without setting a parent and list!" unless self.jason_parent && self.jason_parent_list
    end

    persist_changes :post
end

#serialise ⇒ Object

converts the data hash (that is, @__jason_data) to JSON format



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# File 'lib/medea/jasonobject.rb', line 149

def serialise
  JSON.generate(@__jason_data)
end

#to_public_url ⇒ Object 



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# File 'lib/medea/jasonobject.rb', line 196

def to_public_url
  to_url :public
end

#to_s ⇒ Object 



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# File 'lib/medea/jasonobject.rb', line 144

def to_s
  jason_key
end

#to_url(mode = :secure) ⇒ Object 



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# File 'lib/medea/jasonobject.rb', line 192

def to_url mode=:secure
  "#{JasonDB::db_auth_url mode}#{self.class.name}/#{self.jason_key}"
end

#update_attributes(attributes) ⇒ Object

object persistence methods



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# File 'lib/medea/jasonobject.rb', line 155

def update_attributes attributes
  @__jason_data = sanitize attributes
  @__jason_state = :dirty unless @__jason_state == :new
  save
end