1 files changed, 92 insertions, 0 deletions
diff --git a/actiontext/lib/action_text/trix_attachment.rb b/actiontext/lib/action_text/trix_attachment.rb
new file mode 100644
index 0000000000..c16c1c090d
--- /dev/null
+++ b/actiontext/lib/action_text/trix_attachment.rb
@@ -0,0 +1,92 @@
+# frozen_string_literal: true
+
+module ActionText
+  class TrixAttachment
+    TAG_NAME = "figure"
+    SELECTOR = "[data-trix-attachment]"
+
+    COMPOSED_ATTRIBUTES = %w( caption presentation )
+    ATTRIBUTES = %w( sgid contentType url href filename filesize width height previewable content ) + COMPOSED_ATTRIBUTES
+    ATTRIBUTE_TYPES = {
+      "previewable" => ->(value) { value.to_s == "true" },
+      "filesize"    => ->(value) { Integer(value.to_s) rescue value },
+      "width"       => ->(value) { Integer(value.to_s) rescue nil },
+      "height"      => ->(value) { Integer(value.to_s) rescue nil },
+      :default      => ->(value) { value.to_s }
+    }
+
+    class << self
+      def from_attributes(attributes)
+        attributes = process_attributes(attributes)
+
+        trix_attachment_attributes = attributes.except(*COMPOSED_ATTRIBUTES)
+        trix_attributes = attributes.slice(*COMPOSED_ATTRIBUTES)
+
+        node = ActionText::HtmlConversion.create_element(TAG_NAME)
+        node["data-trix-attachment"] = JSON.generate(trix_attachment_attributes)
+        node["data-trix-attributes"] = JSON.generate(trix_attributes) if trix_attributes.any?
+
+        new(node)
+      end
+
+      private
+        def process_attributes(attributes)
+          typecast_attribute_values(transform_attribute_keys(attributes))
+        end
+
+        def transform_attribute_keys(attributes)
+          attributes.transform_keys { |key| key.to_s.underscore.camelize(:lower) }
+        end
+
+        def typecast_attribute_values(attributes)
+          attributes.map do |key, value|
+            typecast = ATTRIBUTE_TYPES[key] || ATTRIBUTE_TYPES[:default]
+            [key, typecast.call(value)]
+          end.to_h
+        end
+    end
+
+    attr_reader :node
+
+    def initialize(node)
+      @node = node
+    end
+
+    def attributes
+      @attributes ||= attachment_attributes.merge(composed_attributes).slice(*ATTRIBUTES)
+    end
+
+    def to_html
+      ActionText::HtmlConversion.node_to_html(node)
+    end
+
+    def to_s
+      to_html
+    end
+
+    private
+      def attachment_attributes
+        read_json_object_attribute("data-trix-attachment")
+      end
+
+      def composed_attributes
+        read_json_object_attribute("data-trix-attributes")
+      end
+
+      def read_json_object_attribute(name)
+        read_json_attribute(name) || {}
+      end
+
+      def read_json_attribute(name)
+        if value = node[name]
+          begin
+            JSON.parse(value)
+          rescue => e
+            Rails.logger.error "[#{self.class.name}] Couldn't parse JSON #{value} from NODE #{node.inspect}"
+            Rails.logger.error "[#{self.class.name}] Failed with #{e.class}: #{e.backtrace}"
+            nil
+          end
+        end
+      end
+  end
+end