metadata.rb in ezid-client-0.4.0

- old
+ new

@@ -1,161 +1,117 @@
-require "forwardable"
+require "delegate"
+require_relative "metadata_elements"
 
 module Ezid
   #
   # EZID metadata collection for an identifier
   #
   # @api public
-  class Metadata
-    extend Forwardable
-    include Enumerable
+  #
+  class Metadata < SimpleDelegator
 
-    # The metadata elements hash
-    attr_reader :elements
+    include MetadataElements
 
-    def_delegators :elements, :each, :keys, :values, :empty?, :[], :[]=
-
-    # EZID metadata profiles
-    PROFILES = %w( erc dc datacite crossref )
-
-    # Public status
-    PUBLIC = "public"
-
-    # Reserved status
-    RESERVED = "reserved"
-
-    # Unavailable status
-    UNAVAILABLE = "unavailable"
-    
-    # EZID identifier status values
-    STATUS_VALUES = [PUBLIC, RESERVED, UNAVAILABLE].freeze
-
-    # EZID internal read-only metadata elements
-    INTERNAL_READONLY_ELEMENTS = %w( _owner _ownergroup _created _updated _shadows _shadowedby _datacenter ).freeze
-
-    # EZID internal writable metadata elements
-    INTERNAL_READWRITE_ELEMENTS = %w( _coowners _target _profile _status _export _crossref ).freeze        
-
-    # EZID internal metadata elements
-    INTERNAL_ELEMENTS = (INTERNAL_READONLY_ELEMENTS + INTERNAL_READWRITE_ELEMENTS).freeze
-    
     # EZID metadata field/value separator
     ANVL_SEPARATOR = ": "
 
+    ELEMENT_VALUE_SEPARATOR = " | "
+
     # Characters to escape in element values on output to EZID
+    # @see http://ezid.cdlib.org/doc/apidoc.html#request-response-bodies
     ESCAPE_VALUES_RE = /[%\r\n]/
 
-    ESCAPE_KEYS_RE = /[%:\r\n]/
+    # Characters to escape in element names on output to EZID
+    # @see http://ezid.cdlib.org/doc/apidoc.html#request-response-bodies
+    ESCAPE_NAMES_RE = /[%:\r\n]/
 
     # Character sequence to unescape from EZID
+    # http://ezid.cdlib.org/doc/apidoc.html#request-response-bodies
     UNESCAPE_RE = /%\h\h/
 
     # A comment line
     COMMENT_RE = /^#.*(\r?\n)?/ 
 
     # A line continuation
     LINE_CONTINUATION_RE = /\r?\n\s+/
 
     # A line ending
     LINE_ENDING_RE = /\r?\n/
-
+    
     def initialize(data={})
-      @elements = coerce(data)
+      super(coerce(data))
     end
 
     # Output metadata in EZID ANVL format
     # @see http://ezid.cdlib.org/doc/apidoc.html#request-response-bodies
     # @return [String] the ANVL output
-    def to_anvl
-      escape_keys.zip(escape_values).map { |e| e.join(ANVL_SEPARATOR) }.join("\n")
+    def to_anvl(include_readonly = true)
+      elements = __getobj__.dup # copy, don't modify!
+      elements.reject! { |k, v| RESERVED_READONLY_ELEMENTS.include?(k) } unless include_readonly
+      escape_elements(elements).map { |e| e.join(ANVL_SEPARATOR) }.join("\n")
     end
 
     def to_s
       to_anvl
     end
 
     # Adds metadata to the collection
     # @param data [String, Hash, Ezid::Metadata] the data to add
     # @return [Ezid::Metadata] the updated metadata
     def update(data)
-      elements.update(coerce(data))
+      __getobj__.update(coerce(data))
       self
     end
 
-    # Identifier status
-    # @return [String] the status
-    def status
-      reader("_status")
+    # Replaces the collection with new metadata
+    # @param data [String, Hash, Ezid::Metadata] the metadata replacing the current metadata
+    # @return [Ezid::Metadata] the replaced metadata
+    def replace(data)
+      __getobj__.replace(coerce(data))
+      self
     end
 
-    # The time the identifier was created
-    # @return [Time] the time
-    def created
-      value = reader("_created")
-      return Time.at(value.to_i) if value
-      value
-    end
-
-    # The time the identifier was last updated
-    # @return [Time] the time
-    def updated
-      value = reader("_updated")
-      return Time.at(value.to_i) if value
-      value
-    end
-
-    # The identifier's preferred metadata profile
-    # @see http://ezid.cdlib.org/doc/apidoc.html#metadata-profiles
-    # @return [String] the profile
-    def profile
-      reader("_profile")
-    end
-
-    # The identifier's target URL
-    # @return [String] the URL
-    def target
-      reader("_target")
-    end
-
     private
 
-    def reader(element)
-      self[element]
-    end
-
-    def writer(element, value)
-      self[element] = value
-    end
-
     # Coerce data into a Hash of elements
     def coerce(data)
       begin
         stringify_keys(data.to_h)
       rescue NoMethodError
         coerce_string(data)
       end
     end
 
+    # Coerce hash keys to strings
     def stringify_keys(hsh)
-      hsh.keys.map(&:to_s).zip(hsh.values).to_h
+      hsh.each_with_object({}) { |(k, v), memo| memo[k.to_s] = v }
     end
 
-    def escape_keys
-      keys.map { |k| escape(ESCAPE_KEYS_RE, k) }
+    # Escape elements hash keys and values
+    def escape_elements(hsh)
+      hsh.each_with_object({}) do |(n, v), memo|
+        memo[escape_name(n)] = escape_value(v)
+      end
     end
 
-    def escape_values
-      values.map { |v| escape(ESCAPE_VALUES_RE, v) }
+    # Escape an element name
+    def escape_name(n)
+      escape(ESCAPE_NAMES_RE, n)
     end
 
-    # Escape value for sending to EZID host
+    # Escape an element value
+    def escape_value(v)
+      escape(ESCAPE_VALUES_RE, v)
+    end
+
+    # Escape string for sending to EZID host
     # @see http://ezid.cdlib.org/doc/apidoc.html#request-response-bodies
     # @param re [Regexp] the regular expression to match for escaping
-    # @param value [String] the value to escape
-    # @return [String] the escaped value
-    def escape(re, value)
-      value.gsub(re) { |m| URI.encode_www_form_component(m, Encoding::UTF_8) }
+    # @param s [String] the string to escape
+    # @return [String] the escaped string
+    def escape(re, s)
+      s.gsub(re) { |m| URI.encode_www_form_component(m.force_encoding(Encoding::UTF_8)) }
     end
 
     # Unescape value from EZID host (or other source)
     # @see http://ezid.cdlib.org/doc/apidoc.html#request-response-bodies
     # @param value [String] the value to unescape
@@ -163,17 +119,19 @@
     def unescape(value)
       value.gsub(UNESCAPE_RE) { |m| URI.decode_www_form_component(m) }
     end
     
     # Coerce a string of metadata (e.g., from EZID host) into a Hash
+    # @note EZID host does not send comments or line continuations.
     # @param data [String] the string to coerce
     # @return [Hash] the hash of coerced data
     def coerce_string(data)
-      data.gsub(COMMENT_RE, "")
-        .gsub(LINE_CONTINUATION_RE, " ")
-        .split(LINE_ENDING_RE)
-        .map { |line| line.split(ANVL_SEPARATOR, 2).map { |v| unescape(v).strip } }
-        .to_h
+      data.gsub!(COMMENT_RE, "")
+      data.gsub!(LINE_CONTINUATION_RE, " ")
+      data.split(LINE_ENDING_RE).each_with_object({}) do |line, memo|
+        element, value = line.split(ANVL_SEPARATOR, 2)
+        memo[unescape(element.strip)] = unescape(value.strip)
+      end
     end
 
   end
 end