merge: 'parse-links' into 'main'

feat: let TD parse links field

See merge request namib-master/libraries/dart_wot!27

lib/src/definitions/link.dart

@@ -0,0 +1,95 @@
+// Copyright 2022 The NAMIB Project Developers. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+//
+// SPDX-License-Identifier: BSD-3-Clause
+
+/// Represents an element of the `links` array in a Thing Description.
+///
+/// A link can be viewed as a statement of the form "link context has a relation
+/// type resource at link target", where the optional target attributes may
+/// further describe the resource.
+class Link {
+  /// Target IRI of a link or submission target of a form.
+  late final Uri href;
+
+  /// Target attribute providing a hint indicating what the media type (see RFC
+  /// 2046) of the result of dereferencing the link should be.
+  String? type;
+
+  /// A link relation type identifies the semantics of a link.
+  String? rel;
+
+  /// Overrides the link context (by default the Thing itself identified by its
+  /// id) with the given URI or IRI.
+  Uri? anchor;
+
+  /// Target attribute that specifies one or more sizes for a referenced icon.
+  ///
+  /// Only applicable for relation type "icon". The value pattern follows
+  /// {Height}x{Width} (e.g., "16x16", "16x16 32x32").
+  String? sizes;
+
+  final List<String> _parsedJsonFields = [];
+
+  /// Additional fields collected during the parsing of a JSON object.
+  final Map<String, dynamic> additionalFields = <String, dynamic>{};
+
+  /// Constructor.
+  Link(
+    String href, {
+    this.type,
+    this.rel,
+    String? anchor,
+    this.sizes,
+    Map<String, dynamic>? additionalFields,
+  })  : href = Uri.parse(href),
+        anchor = anchor != null ? Uri.parse(anchor) : null {
+    if (additionalFields != null) {
+      this.additionalFields.addAll(additionalFields);
+    }
+  }
+
+  /// Creates a new [Link] from a [json] object.
+  Link.fromJson(Map<String, dynamic> json) {
+    // TODO(JKRhb): Check if this can be refactored
+    if (json["href"] is String) {
+      _parsedJsonFields.add("href");
+      final hrefString = json["href"] as String;
+      href = Uri.parse(hrefString);
+    } else {
+      // [href] *must* be initialized.
+      throw ArgumentError("'href' field must exist as a string.", "formJson");
+    }
+
+    if (json["type"] is String) {
+      _parsedJsonFields.add("type");
+      type = json["type"] as String;
+    }
+
+    if (json["rel"] is String) {
+      _parsedJsonFields.add("rel");
+      rel = json["rel"] as String;
+    }
+
+    if (json["anchor"] is String) {
+      _parsedJsonFields.add("anchor");
+      anchor = Uri.parse(json["anchor"] as String);
+    }
+
+    if (json["sizes"] is String) {
+      _parsedJsonFields.add("sizes");
+      sizes = json["sizes"] as String;
+    }
+
+    _addAdditionalFields(json);
+  }
+
+  void _addAdditionalFields(Map<String, dynamic> formJson) {
+    for (final entry in formJson.entries) {
+      if (!_parsedJsonFields.contains(entry.key)) {
+        additionalFields[entry.key] = entry.value;
+      }
+    }
+  }
+}

lib/src/definitions/thing_description.dart

@@ -10,6 +10,7 @@ import 'context_entry.dart';
 import 'interaction_affordances/action.dart';
 import 'interaction_affordances/event.dart';
 import 'interaction_affordances/property.dart';
+import 'link.dart';
 import 'security_scheme.dart';
 import 'thing_model.dart';
 
@@ -47,6 +48,9 @@ class ThingDescription {
   /// A [Map] of [Event] Affordances.
   Map<String, Event> events = {};
 
+  /// A [List] of [Link]s.
+  final List<Link> links = [];
+
   /// The [base] address of this [ThingDescription]. Might be `null`.
   String? base;
 
@@ -116,6 +120,10 @@ class ThingDescription {
     if (securityDefinitions is Map<String, dynamic>) {
       _parseSecurityDefinitions(securityDefinitions);
     }
+    final dynamic links = json["links"];
+    if (links is List<dynamic>) {
+      _parseLinks(links);
+    }
   }
 
   // TODO(JKRhb): Refactor
@@ -167,6 +175,14 @@ class ThingDescription {
   ThingDescription.fromThingModel(ThingModel thingModel)
       : rawThingModel = thingModel;
 
+  void _parseLinks(List<dynamic> json) {
+    for (final link in json) {
+      if (link is Map<String, dynamic>) {
+        links.add(Link.fromJson(link));
+      }
+    }
+  }
+
   void _parseProperties(Map<String, dynamic> json) {
     for (final property in json.entries) {
       if (property.value is Map<String, dynamic>) {

test/dart_wot_test.dart

@@ -5,6 +5,7 @@
 // SPDX-License-Identifier: BSD-3-Clause
 
 import 'package:dart_wot/dart_wot.dart';
+import 'package:dart_wot/src/definitions/link.dart';
 import 'package:test/test.dart';
 
 // TODO(JKRhb): Add proper tests
@@ -38,7 +39,17 @@ void main() {
               }
             ]
           }
-        }
+        },
+        "links": [
+          {
+            "href": "https://example.org",
+            "rel": "test",
+            "anchor": "https://example.org",
+            "type": "test",
+            "sizes": "42",
+            "test": "test"
+          }
+        ]
       }
       ''';
       final parsedTd = ThingDescription(thingDescriptionJson);
@@ -52,6 +63,34 @@ void main() {
       expect(firstContextEntry.value, "http://www.w3.org/ns/td");
       expect(secondContextEntry.key, "@language");
       expect(secondContextEntry.value, "de");
+
+      final parsedLink = parsedTd.links[0];
+      expect(parsedLink.href, Uri.parse("https://example.org"));
+      expect(parsedLink.rel, "test");
+      expect(parsedLink.anchor, Uri.parse("https://example.org"));
+      expect(parsedLink.type, "test");
+      expect(parsedLink.sizes, "42");
+      expect(parsedLink.additionalFields["test"], "test");
+    });
+
+    test('Link Tests', () {
+      final link = Link("https://example.org",
+          type: "test",
+          rel: "test",
+          anchor: "https://example.org",
+          sizes: "42",
+          additionalFields: <String, dynamic>{"test": "test"});
+      expect(link.href, Uri.parse("https://example.org"));
+      expect(link.rel, "test");
+      expect(link.anchor, Uri.parse("https://example.org"));
+      expect(link.type, "test");
+      expect(link.sizes, "42");
+      expect(link.additionalFields["test"], "test");
+
+      final link2 = Link("https://example.org");
+      expect(link2.href, Uri.parse("https://example.org"));
+      expect(link2.anchor, null);
+      expect(link2.additionalFields, <String, dynamic>{});
     });
   });
 }