feat: add (experimental) coaps support

eclipse-thingweb · May 21, 2022 · 40c7b96 · 40c7b96
1 parent 9e2b2b2
commit 40c7b96
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Showing 4 changed files with 89 additions and 12 deletions.
diff --git a/lib/src/binding_coap/coap_client.dart b/lib/src/binding_coap/coap_client.dart
@@ -9,6 +9,7 @@ import 'dart:convert';
 import 'package:coap/coap.dart' as coap;
 import 'package:coap/config/coap_config_default.dart';
 import 'package:curie/curie.dart';
+import 'package:dart_wot/src/definitions/credentials/psk_credentials.dart';
 
 import '../core/content.dart';
 import '../core/operation_type.dart';
@@ -113,7 +114,30 @@ class _InternalCoapConfig extends CoapConfigDefault {
   @override
   int preferredBlockSize;
 
-  _InternalCoapConfig(this.preferredBlockSize);
+  @override
+  coap.DtlsBackend? dtlsBackend;
+
+  final Form _form;
+
+  _InternalCoapConfig(CoapConfig coapConfig, this._form)
+      : preferredBlockSize =
+            coapConfig.blocksize ?? coap.CoapConstants.preferredBlockSize {
+    if (!_dtlsNeeded) {
+      return;
+    }
+
+    if (_hasPskCredentials(_form) && coapConfig.useTinyDtls) {
+      dtlsBackend = coap.DtlsBackend.TinyDtls;
+    } else if (coapConfig.useOpenSsl) {
+      dtlsBackend = coap.DtlsBackend.OpenSsl;
+    }
+  }
+
+  bool get _dtlsNeeded => _form.href.startsWith("coaps");
+}
+
+bool _hasPskCredentials(Form form) {
+  return form.credentials.whereType<PskCredentials>().isNotEmpty;
 }
 
 class _CoapRequest {
@@ -137,9 +161,11 @@ class _CoapRequest {
   _CoapRequest(
     this._form,
     this._requestMethod,
-    _InternalCoapConfig _coapConfig, [
+    CoapConfig _coapConfig, [
     this._subprotocol,
-  ])  : _coapClient = coap.CoapClient(Uri.parse(_form.href), _coapConfig),
+  ])  : _coapClient = coap.CoapClient(
+            Uri.parse(_form.href), _InternalCoapConfig(_coapConfig, _form),
+            pskCredentialsCallback: _createPskCallback(_form)),
         _requestUri = Uri.parse(_form.href);
 
   // TODO(JKRhb): blockwise parameters cannot be handled at the moment due to
@@ -181,6 +207,41 @@ class _CoapRequest {
     return response;
   }
 
+  static coap.PskCredentials? _retrievePskCredentials(Form form) {
+    final pskCredentialsList = form.credentials.whereType<PskCredentials>();
+
+    for (final pskCredentials in pskCredentialsList) {
+      final identity =
+          pskCredentials.identity ?? pskCredentials.securityScheme?.identity;
+
+      if (identity == null) {
+        continue;
+      }
+
+      final preSharedKey = pskCredentials.preSharedKey;
+
+      return coap.PskCredentials(
+          identity: identity, preSharedKey: preSharedKey);
+    }
+
+    return null;
+  }
+
+  static coap.PskCredentialsCallback? _createPskCallback(Form form) {
+    if (!_hasPskCredentials(form)) {
+      return null;
+    }
+
+    final pskCredentials = _retrievePskCredentials(form);
+
+    if (pskCredentials == null) {
+      throw CoapBindingException("No client Identity found for CoAPS request!");
+    }
+
+    // TODO(JKRhb): Should the identityHint be handled?
+    return (identityHint) => pskCredentials;
+  }
+
   int _determineContentFormat(_ContentFormatType _contentFormatType) {
     final curieString =
         _coapPrefixMapping.expandCurieString(_contentFormatType.stringValue);
@@ -291,10 +352,8 @@ class CoapClient extends ProtocolClient {
     final requestMethod = _getRequestMethod(form, operationType);
     final _Subprotocol? subprotocol =
         _determineSubprotocol(form, operationType);
-    final internalCoapConfig = _InternalCoapConfig(
-        _coapConfig?.blocksize ?? coap.CoapConstants.preferredBlockSize);
-    final request =
-        _CoapRequest(form, requestMethod, internalCoapConfig, subprotocol);
+    final coapConfig = _coapConfig ?? CoapConfig();
+    final request = _CoapRequest(form, requestMethod, coapConfig, subprotocol);
     _pendingRequests.add(request);
     return request;
   }

diff --git a/lib/src/binding_coap/coap_client_factory.dart b/lib/src/binding_coap/coap_client_factory.dart
@@ -13,7 +13,7 @@ import 'coap_config.dart';
 /// A [ProtocolClientFactory] that produces CoAP clients.
 class CoapClientFactory extends ProtocolClientFactory {
   @override
-  Set<String> get schemes => {"coap"};
+  Set<String> get schemes => {"coap", "coaps"};
 
   /// The [CoapConfig] used to configure new clients.
   final CoapConfig? coapConfig;

diff --git a/lib/src/binding_coap/coap_config.dart b/lib/src/binding_coap/coap_config.dart
@@ -9,9 +9,24 @@ class CoapConfig {
   /// The port number used by a client or server. Defaults to 5683.
   final int port;
 
+  /// The coaps port number used by a client or server. Defaults to 5684.
+  final int securePort;
+
   /// The preferred block size for blockwise transfer.
   final int? blocksize;
 
+  /// Indicates if tinydtls is available as a DTLS backend.
+  final bool useTinyDtls;
+
+  /// Indicates if openSSL is available as a DTLS backend.
+  final bool useOpenSsl;
+
   /// Creates a new [CoapConfig] object.
-  CoapConfig({this.port = 5683, this.blocksize});
+  CoapConfig({
+    this.port = 5683,
+    this.securePort = 5684,
+    this.blocksize,
+    this.useTinyDtls = false,
+    this.useOpenSsl = false,
+  });
 }
diff --git a/lib/src/core/consumed_thing.dart b/lib/src/core/consumed_thing.dart
@@ -100,9 +100,12 @@ class ConsumedThing implements scripting_api.ConsumedThing {
             '$formIndex"');
       }
     } else {
-      foundForm = forms.firstWhere((form) =>
-          hasClientFor(Uri.parse(form.href).scheme) &&
-          _supportsOperationType(form, affordanceType, operationType));
+      foundForm = forms.firstWhere(
+          (form) =>
+              hasClientFor(Uri.parse(form.href).scheme) &&
+              _supportsOperationType(form, affordanceType, operationType),
+          // TODO(JKRhb): Add custom Exception
+          orElse: () => throw Exception("No matching form found!"));
       final scheme = Uri.parse(foundForm.href).scheme;
       client = servient.clientFor(scheme);
     }