a guid is at most 255 chars long.

lib/diaspora_federation/validators/rules/guid.rb

@@ -2,7 +2,7 @@ module Validation
   module Rule
     # GUID validation rule
     #
-    # Valid is a +String+ that is at least 16 chars long and contains only:
+    # Valid is a +String+ that is at least 16 and at most 255 chars long. It contains only:
     # * Letters: a-z
     # * Numbers: 0-9
     # * Special chars: '-', '_', '@', '.' and ':'
@@ -30,7 +30,7 @@ module Validation
 
       # Determines if value is a valid +GUID+
       def valid_value?(value)
-        params[:nilable] && value.nil? || value.is_a?(String) && value.downcase =~ /\A[0-9a-z\-_@.:]{16,}\z/
+        params[:nilable] && value.nil? || value.is_a?(String) && value.downcase =~ /\A[0-9a-z\-_@.:]{16,255}\z/
       end
     end
   end

spec/lib/diaspora_federation/validators/rules/guid_spec.rb

@@ -61,6 +61,14 @@ describe Validation::Rule::Guid do
       expect(validator.errors).to include(:guid)
     end
 
+    it "fails if the string is too long" do
+      validator = Validation::Validator.new(OpenStruct.new(guid: "a" * 256))
+      validator.rule(:guid, :guid)
+
+      expect(validator).not_to be_valid
+      expect(validator.errors).to include(:guid)
+    end
+
     it "fails if the string contains invalid chars" do
       validator = Validation::Validator.new(OpenStruct.new(guid: "ghijklmnopqrstuvwxyz++"))
       validator.rule(:guid, :guid)