Merge pull request #178 from eclipse-thingweb/serialization

feat!: implement proper serialization logic

lib/src/binding_coap/coap_client.dart

@@ -284,7 +284,7 @@ final class CoapClient extends ProtocolClient
 
     return AuthServerRequestCreationHint(
       authorizationServer:
-          aceSecurityScheme.as ?? creationHint?.authorizationServer,
+          aceSecurityScheme.as?.toString() ?? creationHint?.authorizationServer,
       scope: scope ?? creationHint?.scope,
       audience: aceSecurityScheme.audience ?? creationHint?.audience,
       clientNonce: creationHint?.clientNonce,

lib/src/binding_coap/coap_extensions.dart

@@ -116,7 +116,7 @@ extension CoapFormExtension on AugmentedForm {
 extension CoapExpectedResponseExtension on ExpectedResponse {
   T? _obtainVocabularyTerm<T>(String vocabularyTerm) {
     final curieString = coapPrefixMapping.expandCurieString(vocabularyTerm);
-    final formDefinition = additionalFields?[curieString];
+    final formDefinition = additionalFields[curieString];
 
     if (formDefinition is T) {
       return formDefinition;

lib/src/core/definitions/additional_expected_response.dart

@@ -9,17 +9,18 @@ import "package:curie/curie.dart";
 import "package:meta/meta.dart";
 
 import "extensions/json_parser.dart";
+import "extensions/serializable.dart";
 
 /// Communication metadata describing the expected response message for the
 /// primary response.
 @immutable
-class AdditionalExpectedResponse {
+class AdditionalExpectedResponse implements Serializable {
   /// Constructs a new [AdditionalExpectedResponse] object from a [contentType].
   const AdditionalExpectedResponse(
     this.contentType, {
     this.schema,
     this.success = false,
-    this.additionalFields,
+    this.additionalFields = const {},
   });
 
   /// Creates an [AdditionalExpectedResponse] from a [json] object.
@@ -61,7 +62,7 @@ class AdditionalExpectedResponse {
   final String? schema;
 
   /// Any other additional field will be included in this [Map].
-  final Map<String, dynamic>? additionalFields;
+  final Map<String, dynamic> additionalFields;
 
   @override
   bool operator ==(Object other) {
@@ -79,4 +80,22 @@ class AdditionalExpectedResponse {
   @override
   int get hashCode =>
       Object.hash(success, schema, contentType, additionalFields);
+
+  @override
+  Map<String, dynamic> toJson() {
+    final result = {
+      "contentType": contentType,
+      ...additionalFields,
+    };
+
+    if (success) {
+      result["success"] = success;
+    }
+
+    if (schema != null) {
+      result["schema"] = schema;
+    }
+
+    return result;
+  }
 }

lib/src/core/definitions/context.dart

@@ -8,12 +8,14 @@ import "package:collection/collection.dart";
 import "package:curie/curie.dart";
 import "package:meta/meta.dart";
 
+import "extensions/serializable.dart";
+
 const _tdVersion10ContextUrl = "https://www.w3.org/2019/wot/td/v1";
 const _tdVersion11ContextUrl = "https://www.w3.org/2022/wot/td/v1.1";
 
 /// Represents the JSON-LD `@context` of a Thing Description or Thing Model.
 @immutable
-final class Context {
+final class Context implements Serializable {
   /// Creates a new context from a list of [contextEntries].
   Context(this.contextEntries)
       : prefixMapping = _createPrefixMapping(contextEntries);
@@ -114,6 +116,28 @@ final class Context {
 
   @override
   int get hashCode => Object.hashAll(contextEntries);
+
+  @override
+  List<dynamic> toJson() {
+    final result = <dynamic>[];
+    final mapResult = <String, String>{};
+
+    for (final contextEntry in contextEntries) {
+      switch (contextEntry) {
+        case SingleContextEntry(:final uri):
+          result.add(uri.toString());
+        case MapContextEntry(:final key, :final value):
+          //TODO: Could there be duplicate keys?
+          mapResult[key] = value;
+      }
+    }
+
+    if (mapResult.isNotEmpty) {
+      result.add(mapResult);
+    }
+
+    return result;
+  }
 }
 
 /// Base class for `@context` entries.

lib/src/core/definitions/data_schema.dart

@@ -8,14 +8,16 @@ import "package:curie/curie.dart";
 import "package:meta/meta.dart";
 
 import "extensions/json_parser.dart";
+import "extensions/json_serializer.dart";
+import "extensions/serializable.dart";
 
 /// Metadata that describes the data format used. It can be used for validation.
 ///
 /// See W3C WoT Thing Description specification, [section 5.3.2.1][spec link].
 ///
 /// [spec link]: https://w3c.github.io/wot-thing-description/#dataschema
 @immutable
-class DataSchema {
+class DataSchema implements Serializable {
   /// Constructor
   const DataSchema({
     this.atType,
@@ -47,8 +49,7 @@ class DataSchema {
     this.pattern,
     this.contentEncoding,
     this.contentMediaType,
-    this.rawJson,
-    this.additionalFields,
+    this.additionalFields = const {},
   });
 
   // TODO: Consider creating separate classes for each data type.
@@ -83,7 +84,7 @@ class DataSchema {
     final minimum = json.parseField<num>("minimum", parsedFields);
     final exclusiveMinimum =
         json.parseField<num>("exclusiveMinimum", parsedFields);
-    final maximum = json.parseField<num>("minimum", parsedFields);
+    final maximum = json.parseField<num>("maximum", parsedFields);
     final exclusiveMaximum =
         json.parseField<num>("exclusiveMaximum", parsedFields);
     final multipleOf = json.parseField<num>("multipleOf", parsedFields);
@@ -136,7 +137,6 @@ class DataSchema {
       contentMediaType: contentMediaType,
       oneOf: oneOf,
       properties: properties,
-      rawJson: json,
       additionalFields: additionalFields,
     );
   }
@@ -274,8 +274,63 @@ class DataSchema {
   final String? contentMediaType;
 
   /// Additional fields that could not be deserialized as class members.
-  final Map<String, dynamic>? additionalFields;
-
-  /// The original JSON object that was parsed when creating this [DataSchema].
-  final Map<String, dynamic>? rawJson;
+  final Map<String, dynamic> additionalFields;
+
+  @override
+  Map<String, dynamic> toJson() {
+    final result = {
+      ...additionalFields,
+    };
+
+    final keyValuePairs = [
+      ("@type", atType),
+      ("title", title),
+      ("titles", titles),
+      ("description", description),
+      ("descriptions", descriptions),
+      ("const", constant),
+      ("default", defaultValue),
+      ("enum", enumeration),
+      ("readOnly", readOnly),
+      ("writeOnly", writeOnly),
+      ("format", format),
+      ("unit", unit),
+      ("type", type),
+      ("minimum", minimum),
+      ("exclusiveMinimum", exclusiveMinimum),
+      ("maximum", maximum),
+      ("exclusiveMaximum", exclusiveMaximum),
+      ("multipleOf", multipleOf),
+      ("items", items),
+      ("minItems", minItems),
+      ("maxItems", maxItems),
+      ("required", required),
+      ("minLength", minLength),
+      ("maxLength", maxLength),
+      ("pattern", pattern),
+      ("contentEncoding", contentEncoding),
+      ("contentMediaType", contentMediaType),
+      ("oneOf", oneOf),
+      ("properties", properties),
+    ];
+
+    for (final (key, value) in keyValuePairs) {
+      final dynamic convertedValue;
+
+      switch (value) {
+        case null:
+          continue;
+        case List<Serializable>():
+          convertedValue = value.toJson();
+        case Map<String, Serializable>():
+          convertedValue = value.toJson();
+        default:
+          convertedValue = value;
+      }
+
+      result[key] = convertedValue;
+    }
+
+    return result;
+  }
 }

lib/src/core/definitions/expected_response.dart

@@ -8,15 +8,16 @@ import "package:curie/curie.dart";
 import "package:meta/meta.dart";
 
 import "extensions/json_parser.dart";
+import "extensions/serializable.dart";
 
 /// Communication metadata describing the expected response message for the
 /// primary response.
 @immutable
-class ExpectedResponse {
+class ExpectedResponse implements Serializable {
   /// Constructs a new [ExpectedResponse] object from a [contentType].
   const ExpectedResponse(
     this.contentType, {
-    this.additionalFields,
+    this.additionalFields = const {},
   });
 
   /// Creates an [ExpectedResponse] from a [json] object.
@@ -38,5 +39,11 @@ class ExpectedResponse {
   final String contentType;
 
   /// Any other additional field will be included in this [Map].
-  final Map<String, dynamic>? additionalFields;
+  final Map<String, dynamic> additionalFields;
+
+  @override
+  Map<String, dynamic> toJson() => {
+        "contentType": contentType,
+        ...additionalFields,
+      };
 }

lib/src/core/definitions/extensions/json_parser.dart

@@ -55,6 +55,12 @@ extension ParseField on Map<String, dynamic> {
       return fieldValue;
     }
 
+    if ((T == Map<String, dynamic>) &&
+        fieldValue is Map &&
+        fieldValue.isEmpty) {
+      return <String, dynamic>{} as T;
+    }
+
     throw FormatException("Expected $T, got ${fieldValue.runtimeType}");
   }
 
@@ -151,6 +157,10 @@ extension ParseField on Map<String, dynamic> {
       return null;
     }
 
+    if (fieldValue is Map && fieldValue.isEmpty) {
+      return {};
+    }
+
     if (fieldValue is Map<String, dynamic>) {
       final Map<String, T> result = {};
 

lib/src/core/definitions/extensions/json_serializer.dart

@@ -0,0 +1,29 @@
+// Copyright 2024 Contributors to the Eclipse Foundation. 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
+
+import "../form.dart";
+import "../link.dart";
+import "serializable.dart";
+
+/// Extension that provides JSON serialization for [List]s of [Link]s.
+extension SerializableList on List<Serializable> {
+  /// Converts this [List] of [Serializable] elements to JSON.
+  List<dynamic> toJson() =>
+      map((listItem) => listItem.toJson()).toList(growable: false);
+}
+
+/// Extension that provides JSON serialization for [List]s of [Form]s.
+extension SerializableMap on Map<String, Serializable> {
+  /// Converts this [Map] of [Serializable] key-value pairs to JSON.
+  Map<String, dynamic> toJson() =>
+      map((key, value) => MapEntry(key, value.toJson()));
+}
+
+/// Extension that provides JSON serialization for [List]s of [Uri]s.
+extension UriListToJsonExtension on List<Uri> {
+  /// Converts this [List] of [Uri]s to JSON.
+  List<String> toJson() => map((uri) => uri.toString()).toList(growable: false);
+}

lib/src/core/definitions/extensions/serializable.dart

@@ -0,0 +1,11 @@
+// Copyright 2024 Contributors to the Eclipse Foundation. 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
+
+/// Interface for converting a class object [toJson].
+abstract interface class Serializable {
+  /// Converts this class object into a JSON value.
+  dynamic toJson();
+}

lib/src/core/definitions/form.dart

@@ -10,11 +10,12 @@ import "package:meta/meta.dart";
 import "additional_expected_response.dart";
 import "expected_response.dart";
 import "extensions/json_parser.dart";
+import "extensions/serializable.dart";
 import "operation_type.dart";
 
 /// Contains the information needed for performing interactions with a Thing.
 @immutable
-class Form {
+class Form implements Serializable {
   /// Creates a new [Form] object.
   ///
   /// An [href] has to be provided. A [contentType] is optional.
@@ -128,4 +129,49 @@ class Form {
 
   /// Additional fields collected during the parsing of a JSON object.
   final Map<String, dynamic> additionalFields = {};
+
+  @override
+  Map<String, dynamic> toJson() {
+    final result = {
+      "href": href.toString(),
+      "contentType": contentType,
+      ...additionalFields,
+    };
+
+    if (subprotocol != null) {
+      result["subprotocol"] = subprotocol;
+    }
+
+    final op = this.op;
+    if (op != null) {
+      result["op"] =
+          op.map((opValue) => opValue.toString()).toList(growable: false);
+    }
+
+    if (contentCoding != null) {
+      result["contentCoding"] = contentCoding;
+    }
+
+    if (security != null) {
+      result["security"] = security;
+    }
+
+    if (scopes != null) {
+      result["scopes"] = scopes;
+    }
+
+    final response = this.response;
+    if (response != null) {
+      result["response"] = response.toJson();
+    }
+
+    final additionalResponses = this.additionalResponses;
+    if (additionalResponses != null) {
+      result["additionalResponses"] = additionalResponses
+          .map((additionalResponse) => additionalResponse.toJson())
+          .toList(growable: false);
+    }
+
+    return result;
+  }
 }