lib/duracloud/content.rb in duracloud-client-0.1.5 vs lib/duracloud/content.rb in duracloud-client-0.2.0

@@ -1,56 +1,48 @@
-require "stringio"
 require "active_model"
 
 module Duracloud
   #
   # A piece of content in DuraCloud
   #
   class Content
+    include ActiveModel::Model
     include ActiveModel::Dirty
     include Persistence
     include HasProperties
 
     CHUNK_SIZE = 1024 * 16
 
     after_save :changes_applied
 
     # Does the content exist in DuraCloud?
-    # @see .new for arguments
     # @return [Boolean] whether the content exists
-    def self.exist?(*args)
-      find(*args) && true
+    # @raise [Duracloud::MessageDigestError] the provided digest in the :md5 attribute
+    #   does not match the stored value
+    def self.exist?(params={})
+      find(params) && true
     rescue NotFoundError
       false
     end
 
     # Find content in DuraCloud.
-    # @see .new for arguments
     # @return [Duraclound::Content] the content
     # @raise [Duracloud::NotFoundError] the space, content, or store does not exist.
-    def self.find(*args)
-      new(*args) { |content| content.load_properties }
+    # @raise [Duracloud::MessageDigestError] the provided digest in the :md5 attribute
+    #   does not match the stored value
+    def self.find(params={})
+      new(params).tap do |content|
+        content.load_properties
+      end
     end
 
-    attr_reader :space_id, :content_id, :store_id
+    attr_accessor :space_id, :content_id, :store_id
     alias_method :id, :content_id
+    validates_presence_of :space_id, :content_id
 
-    define_attribute_methods :content_type, :body
+    define_attribute_methods :content_type, :body, :md5
 
-    # @param space_id [String] The space ID (required)
-    # @param content_id [String] The content ID (required)
-    # @param store_id [String] the store ID (optional)
-    # @example
-    #   new("myspace", "mycontent.txt")
-    def initialize(space_id, content_id, store_id = nil)
-      @content_id = content_id
-      @space_id = space_id
-      @store_id = store_id
-      @body, @content_type = nil, nil
-      yield self if block_given?
-    end
-
     # Return the space associated with this content.
     # @return [Duracloud::Space] the space.
     # @raise [Duracloud::NotFoundError] the space or store does not exist.
     def space
       Space.find(space_id, store_id)
@@ -64,17 +56,19 @@
 
     # @api private
     # @raise [Duracloud::NotFoundError] the content does not exist in DuraCloud.
     def load_body
       response = Client.get_content(*args, **query)
+      set_md5!(response)
       @body = response.body # don't use setter b/c marks as dirty
       persisted!
     end
 
     def load_properties
       super do |response|
-        # don't mark content_type as changed
+        # don't mark content_type or md5 as changed
+        set_md5!(response)
         @content_type = response.content_type
       end
     end
 
     def body=(str_or_io)
@@ -102,12 +96,32 @@
 
     def content_type
       @content_type
     end
 
+    def md5=(val)
+      md5_will_change! unless val == @md5
+      @md5 = val
+    end
+
+    def md5
+      @md5
+    end
+
     private
 
+    def set_md5!(response)
+      if md5
+        if md5 != response.md5
+          raise MessageDigestError,
+                "Expected MD5 digest (#{md5}) does not match response header: #{response.md5}"
+        end
+      else
+        @md5 = response.md5
+      end
+    end
+
     def io_like?
       body.respond_to?(:read) && body.respond_to?(:rewind)
     end
 
     def set_properties
@@ -117,18 +131,18 @@
       Client.set_content_properties(*args, **options)
     end
 
     def store
       headers = {
-        "Content-MD5"  => md5,
+        "Content-MD5"  => md5 || calculate_md5,
         "Content-Type" => content_type || "application/octet-stream"
       }
       headers.merge!(properties)
       options = { body: body, headers: headers, query: query }
       Client.store_content(*args, **options)
     end
 
-    def md5
+    def calculate_md5
       digest = Digest::MD5.new
       if io_like?
         body.rewind
         while chunk = body.read(CHUNK_SIZE) do
           digest << chunk