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author | David Heinemeier Hansson <david@loudthinking.com> | 2006-06-04 00:33:52 +0000 |
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committer | David Heinemeier Hansson <david@loudthinking.com> | 2006-06-04 00:33:52 +0000 |
commit | 2e65e8ccc68c56607fb86f6668d4f886165ace5e (patch) | |
tree | c402f1a4e8eb66493ba0471124dba9cd4c2d02f2 /activerecord/lib/active_record/xml_serialization.rb | |
parent | 15b022a74fed4264a24da78566ebaaff29df29eb (diff) | |
download | rails-2e65e8ccc68c56607fb86f6668d4f886165ace5e.tar.gz rails-2e65e8ccc68c56607fb86f6668d4f886165ace5e.tar.bz2 rails-2e65e8ccc68c56607fb86f6668d4f886165ace5e.zip |
Refactored ActiveRecord::Base.to_xml to become a delegate for XmlSerializer, which restores sanity to the mega method. This refactoring also reinstates the opinions that type="string" is redundant and ugly and nil-differentiation is not a concern of serialization [DHH]
git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@4431 5ecf4fe2-1ee6-0310-87b1-e25e094e27de
Diffstat (limited to 'activerecord/lib/active_record/xml_serialization.rb')
-rw-r--r-- | activerecord/lib/active_record/xml_serialization.rb | 309 |
1 files changed, 309 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/xml_serialization.rb b/activerecord/lib/active_record/xml_serialization.rb new file mode 100644 index 0000000000..c8a4e2526c --- /dev/null +++ b/activerecord/lib/active_record/xml_serialization.rb @@ -0,0 +1,309 @@ +module ActiveRecord #:nodoc: + module XmlSerialization + # Builds an XML document to represent the model. Some configuration is + # availble through +options+, however more complicated cases should use + # override ActiveRecord's to_xml. + # + # By default the generated XML document will include the processing + # instruction and all object's attributes. For example: + # + # <?xml version="1.0" encoding="UTF-8"?> + # <topic> + # <title>The First Topic</title> + # <author-name>David</author-name> + # <id type="integer">1</id> + # <approved type="boolean">false</approved> + # <replies-count type="integer">0</replies-count> + # <bonus-time type="datetime">2000-01-01T08:28:00+12:00</bonus-time> + # <written-on type="datetime">2003-07-16T09:28:00+1200</written-on> + # <content>Have a nice day</content> + # <author-email-address>david@loudthinking.com</author-email-address> + # <parent-id></parent-id> + # <last-read type="date">2004-04-15</last-read> + # </topic> + # + # This behavior can be controlled with :only, :except, + # :skip_instruct, :skip_types and :dasherize. The :only and + # :except options are the same as for the #attributes method. + # The default is to dasherize all column names, to disable this, + # set :dasherize to false. To not have the column type included + # in the XML output, set :skip_types to false. + # + # For instance: + # + # topic.to_xml(:skip_instruct => true, :except => [ :id, :bonus_time, :written_on, :replies_count ]) + # + # <topic> + # <title>The First Topic</title> + # <author-name>David</author-name> + # <approved type="boolean">false</approved> + # <content>Have a nice day</content> + # <author-email-address>david@loudthinking.com</author-email-address> + # <parent-id></parent-id> + # <last-read type="date">2004-04-15</last-read> + # </topic> + # + # To include first level associations use :include + # + # firm.to_xml :include => [ :account, :clients ] + # + # <?xml version="1.0" encoding="UTF-8"?> + # <firm> + # <id type="integer">1</id> + # <rating type="integer">1</rating> + # <name>37signals</name> + # <clients> + # <client> + # <rating type="integer">1</rating> + # <name>Summit</name> + # </client> + # <client> + # <rating type="integer">1</rating> + # <name>Microsoft</name> + # </client> + # </clients> + # <account> + # <id type="integer">1</id> + # <credit-limit type="integer">50</credit-limit> + # </account> + # </firm> + # + # To include any methods on the object(s) being called use :methods + # + # firm.to_xml :methods => [ :calculated_earnings, :real_earnings ] + # + # <firm> + # # ... normal attributes as shown above ... + # <calculated-earnings>100000000000000000</calculated-earnings> + # <real-earnings>5</real-earnings> + # </firm> + # + # To call any Proc's on the object(s) use :procs. The Proc's + # are passed a modified version of the options hash that was + # given to #to_xml. + # + # proc = Proc.new { |options| options[:builder].tag!('abc', 'def') } + # firm.to_xml :procs => [ proc ] + # + # <firm> + # # ... normal attributes as shown above ... + # <abc>def</abc> + # </firm> + # + # You may override the to_xml method in your ActiveRecord::Base + # subclasses if you need to. The general form of doing this is + # + # class IHaveMyOwnXML < ActiveRecord::Base + # def to_xml(options = {}) + # options[:indent] ||= 2 + # xml = options[:builder] ||= Builder::XmlMarkup.new(:indent => options[:indent]) + # xml.instruct! unless options[:skip_instruct] + # xml.level_one do + # xml.tag!(:second_level, 'content') + # end + # end + # end + def to_xml(options = {}) + XmlSerializer.new(self, options).to_s + end + end + + class XmlSerializer #:nodoc: + attr_reader :options + + def initialize(record, options = {}) + @record, @options = record, options + end + + def builder + @builder ||= begin + options[:indent] ||= 2 + builder = options[:builder] ||= Builder::XmlMarkup.new(:indent => options[:indent]) + + unless options[:skip_instruct] + builder.instruct! + options[:skip_instruct] = true + end + + builder + end + end + + def root + root = (options[:root] || @record.class.to_s.underscore).to_s + dasherize? ? root.dasherize : root + end + + def dasherize? + !options.has_key?(:dasherize) || options[:dasherize] + end + + + # To replicate the behavior in ActiveRecord#attributes, + # :except takes precedence over :only. If :only is not set + # for a N level model but is set for the N+1 level models, + # then because :except is set to a default value, the second + # level model can have both :except and :only set. So if + # :only is set, always delete :except. + def serializable_attributes + attribute_names = @record.attribute_names + + if options[:only] + options.delete(:except) + attribute_names = attribute_names & Array(options[:only]).collect { |n| n.to_s } + else + options[:except] = Array(options[:except]) | Array(@record.class.inheritance_column) + attribute_names = attribute_names - options[:except].collect { |n| n.to_s } + end + + attribute_names.collect { |name| Attribute.new(name, @record) } + end + + def serializable_method_attributes + Array(options.delete(:methods)).collect { |name| MethodAttribute.new(name.to_s, @record) } + end + + + def add_attributes + (serializable_attributes + serializable_method_attributes).each do |attribute| + add_tag(attribute) + end + end + + def add_includes + if include_associations = options.delete(:include) + root_only_or_except = { :except => options[:except], + :only => options[:only] } + + include_has_options = include_associations.is_a?(Hash) + + for association in include_has_options ? include_associations.keys : Array(include_associations) + association_options = include_has_options ? include_associations[association] : root_only_or_except + + opts = options.merge(association_options) + + case @record.class.reflect_on_association(association).macro + when :has_many, :has_and_belongs_to_many + records = @record.send(association).to_a + unless records.empty? + tag = records.first.class.to_s.underscore.pluralize + tag = tag.dasherize if dasherize? + + builder.tag!(tag) do + records.each { |r| r.to_xml(opts) } + end + end + when :has_one, :belongs_to + if record = @record.send(association) + record.to_xml(opts.merge(:root => association)) + end + end + end + end + end + + def add_procs + if procs = options.delete(:procs) + [ *procs ].each do |proc| + proc.call(options) + end + end + end + + + def add_tag(attribute) + if attribute.needs_encoding? + builder.tag!( + dasherize? ? attribute.name.dasherize : attribute.name, + attribute.value.to_s, + attribute.decorations(!options[:skip_types]) + ) + else + builder.tag!( + dasherize? ? attribute.name.dasherize : attribute.name, + attribute.decorations(!options[:skip_types])) do + builder << attribute.value.to_s + end + end + end + + def serialize + builder.tag!(root) do + add_attributes + add_includes + add_procs + end + end + + alias_method :to_s, :serialize + + class Attribute #:nodoc: + attr_reader :name, :value, :type + + def initialize(name, record) + @name, @record = name, record + + @type = compute_type + @value = compute_value + end + + # There is a significant speed improvement if the value + # does not need to be escaped, as #tag! escapes all values + # to ensure that valid XML is generated. For known binary + # values, it is at least an order of magnitude faster to + # Base64 encode binary values and directly put them in the + # output XML than to pass the original value or the Base64 + # encoded value to the #tag! method. It definitely makes + # no sense to Base64 encode the value and then give it to + # #tag!, since that just adds additional overhead. + def needs_encoding? + ![ :binary, :date, :datetime, :boolean, :float, :integer ].include?(type) + end + + def decorations(include_types = true) + decorations = {} + + if type == :binary + decorations[:encoding] = 'base64' + end + + if include_types && type != :string + decorations[:type] = type + end + + decorations + end + + protected + def compute_type + type = @record.class.columns_hash[name].type + + case type + when :text + :string + when :time + :datetime + else + type + end + end + + def compute_value + value = @record.send(name) + + if formatter = Hash::XML_FORMATTING[type.to_s] + value ? formatter.call(value) : nil + else + value + end + end + end + + class MethodAttribute < Attribute #:nodoc: + protected + def compute_type + Hash::XML_TYPE_NAMES[@record.send(name).class] || :string + end + end + end +end
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