Add support for custom attributes for item and remove built-in support for Prusa's printable attribute

Author: tomasf

Sources/ThreeMF/Model/Item.swift

@@ -5,30 +5,40 @@ public struct Item: Sendable, XMLElementCodable {
     public var objectID: ResourceID
     public var transform: Matrix3D?
     public var partNumber: String?
-    public var printable: Bool? // Prusa extension
     public var metadata: [Metadata]
+    public var customAttributes: [ExpandedName: String]
 
-    public init(objectID: ResourceID, transform: Matrix3D? = nil, partNumber: String? = nil, metadata: [Metadata] = [], printable: Bool? = nil) {
+    public init(
+        objectID: ResourceID,
+        transform: Matrix3D? = nil,
+        partNumber: String? = nil,
+        metadata: [Metadata] = [],
+        customAttributes: [ExpandedName: String] = [:]
+    ) {
         self.objectID = objectID
         self.transform = transform
         self.partNumber = partNumber
         self.metadata = metadata
-        self.printable = printable
+        self.customAttributes = customAttributes
     }
 
     public func encode(to element: Node) {
         element.setValue(objectID, forAttribute: .objectID)
         element.setValue(transform, forAttribute: .transform)
         element.setValue(partNumber, forAttribute: .partNumber)
-        element.setValue(printable, forAttribute: .printable)
         element.encode(metadata, elementName: Core.metadata, containedIn: Core.metadataGroup)
+        for (name, value) in customAttributes {
+            element.setValue(value, forAttribute: name)
+        }
     }
 
     public init(from element: Node) throws {
         objectID = try element.value(forAttribute: .objectID)
         transform = try element.value(forAttribute: .transform)
         partNumber = try element.value(forAttribute: .partNumber)
-        printable = try element.value(forAttribute: .printable)
         metadata = try element.decode(elementName: Core.metadata, containedIn: Core.metadataGroup)
+
+        let knownAttributes: Set<ExpandedName> = [.objectID, .transform, .partNumber, Core.metadataGroup]
+        customAttributes = element.namespacedAttributes.filter { !knownAttributes.contains($0.key) }
     }
 }

Sources/ThreeMF/Model/Model.swift

@@ -8,6 +8,7 @@ public struct Model: Sendable, XMLElementCodable {
 
     public var requiredExtensions: Set<Namespace>
     public var recommendedExtensions: Set<Namespace>
+    public var customNamespaces: [String: String]
 
     public var metadata: [Metadata]
     public var resources: ResourceContainer
@@ -19,6 +20,7 @@ public struct Model: Sendable, XMLElementCodable {
         languageCode: String? = nil,
         requiredExtensions: Set<Namespace> = [],
         recommendedExtensions: Set<Namespace> = [],
+        customNamespaces: [String: String] = [:], // Prefix: URI
         metadata: [Metadata] = [],
         resources: [any Resource] = [],
         buildItems: [Item] = []
@@ -28,6 +30,7 @@ public struct Model: Sendable, XMLElementCodable {
         self.languageCode = languageCode
         self.requiredExtensions = requiredExtensions
         self.recommendedExtensions = recommendedExtensions
+        self.customNamespaces = customNamespaces
 
         self.metadata = metadata
         self.resources = ResourceContainer(resources: resources)
@@ -50,7 +53,6 @@ public struct Model: Sendable, XMLElementCodable {
         xmlLanguageCode = try element.value(forAttribute: XML.lang)
         languageCode = try element.value(forAttribute: .language)
 
-
         if let requiredExtensionPrefixes: [String] = try element.value(forAttribute: .requiredExtensions) {
             requiredExtensions = Namespace.namespaces(forPrefixes: requiredExtensionPrefixes, in: element)
         } else {
@@ -63,6 +65,9 @@ public struct Model: Sendable, XMLElementCodable {
             recommendedExtensions = []
         }
 
+        let knownNamespaces = Set(Namespace.known.map(\.uri))
+        customNamespaces = element.declaredNamespaces.filter { $0 != nil && knownNamespaces.contains($1) } as! [String: String]
+
         metadata = try element.decode(elementName: Core.metadata)
         resources = try element.decode(elementName: Core.resources)
         buildItems = try element.decode(elementName: Core.item, containedIn: Core.build)

Sources/ThreeMF/Namespace/Attributes.swift

@@ -39,9 +39,6 @@ extension AttributeName where Self == ExpandedName {
     static var p2: Self { attribute("p2") }
     static var p3: Self { attribute("p3") }
 
-    // This is a Prusa extension. It should live in its own namespace, but alas, it does not
-    static var printable: Self { attribute("printable") }
-
     // MARK: - Materials
     static var displayPropertiesID: Self { attribute("displaypropertiesid") }
     static var values: Self { attribute("values") }

Sources/ThreeMF/Package/PackageWriter.swift

@@ -77,6 +77,10 @@ internal extension PackageWriter {
     func xmlDocument() -> Document {
         let modelDocument = Document(model, elementName: Core.model)
 
+        for (prefix, uri) in model.customNamespaces {
+            modelDocument.documentElement?.declareNamespace(uri, forPrefix: prefix)
+        }
+
         for namespaceName in modelDocument.undeclaredNamespaceNames {
             guard let namespace = Namespace.knownNamespace(for: namespaceName) else {
                 assertionFailure("Unknown namespace \(namespaceName)")