feat: add unary data client with get/set support (#35)

lib/client_sdk_dart.dart

@@ -4,6 +4,7 @@
 library;
 
 export 'src/topic_client.dart';
+export 'src/cache_client.dart';
 export 'src/auth/credential_provider.dart';
 export 'src/config/topic_configurations.dart';
 export 'src/messages/values.dart';

lib/src/cache_client.dart

@@ -0,0 +1,40 @@
+import 'package:client_sdk_dart/src/config/cache_configuration.dart';
+import 'package:client_sdk_dart/src/internal/data_client.dart';
+import 'package:client_sdk_dart/src/messages/responses/cache/data/scalar/get_response.dart';
+import 'package:client_sdk_dart/src/messages/responses/cache/data/scalar/set_response.dart';
+import 'package:logging/logging.dart';
+
+import 'auth/credential_provider.dart';
+import 'config/logger.dart';
+import 'messages/values.dart';
+
+abstract class ICacheClient {
+  Future<GetResponse> get(String cacheName, Value value);
+
+  Future<SetResponse> set(String cacheName, Value key, Value value,
+      {Duration? ttl});
+}
+
+class CacheClient implements ICacheClient {
+  final DataClient _dataClient;
+  final Logger _logger = Logger('MomentoCacheClient');
+
+  CacheClient(CredentialProvider credentialProvider,
+      CacheConfiguration configuration, Duration defaultTtl)
+      : _dataClient =
+            DataClient(credentialProvider, configuration, defaultTtl) {
+    _logger.level = determineLoggerLevel(configuration.logLevel);
+    _logger.finest("initializing cache client");
+  }
+
+  @override
+  Future<GetResponse> get(String cacheName, Value value) {
+    return _dataClient.get(cacheName, value);
+  }
+
+  @override
+  Future<SetResponse> set(String cacheName, Value key, Value value,
+      {Duration? ttl}) {
+    return _dataClient.set(cacheName, key, value, ttl: ttl);
+  }
+}

lib/src/internal/data_client.dart

@@ -0,0 +1,88 @@
+import 'package:client_sdk_dart/generated/cacheclient.pbgrpc.dart';
+import 'package:client_sdk_dart/src/config/cache_configuration.dart';
+import 'package:client_sdk_dart/src/errors/errors.dart';
+import 'package:client_sdk_dart/src/messages/responses/cache/data/scalar/get_response.dart';
+import 'package:client_sdk_dart/src/messages/responses/cache/data/scalar/set_response.dart';
+import 'package:fixnum/fixnum.dart';
+import 'package:grpc/grpc.dart';
+
+import '../auth/credential_provider.dart';
+import '../messages/values.dart';
+
+abstract class AbstractDataClient {
+  Future<GetResponse> get(String cacheName, Value key);
+
+  Future<SetResponse> set(String cacheName, Value key, Value value,
+      {Duration? ttl});
+}
+
+class DataClient implements AbstractDataClient {
+  late ClientChannel _channel;
+  late ScsClient _client;
+  late CacheConfiguration _configuration;
+  late Duration _defaultTtl;
+
+  DataClient(CredentialProvider credentialProvider,
+      CacheConfiguration configuration, Duration defaultTtl) {
+    _channel = ClientChannel(credentialProvider.cacheEndpoint);
+    _client = ScsClient(_channel,
+        options: CallOptions(metadata: {
+          'authorization': credentialProvider.apiKey,
+          'agent': 'dart:0.1.0',
+        }, timeout: _configuration.transportStrategy.grpcConfig.deadline));
+    _configuration = configuration;
+    _defaultTtl = defaultTtl;
+  }
+
+  @override
+  Future<GetResponse> get(String cacheName, Value key) async {
+    var request = GetRequest_();
+    request.cacheKey = key.toBinary();
+    try {
+      var resp = await _client.get(request,
+          options: CallOptions(metadata: {
+            'cacheName': cacheName,
+          }));
+
+      switch (resp.result) {
+        case ECacheResult.Miss:
+          return GetMiss();
+        case ECacheResult.Hit:
+          return GetHit(resp.cacheBody);
+        default:
+          return GetError(UnknownException(
+              "unknown cache get error ${resp.result}", null, null));
+      }
+    } catch (e) {
+      if (e is SdkException) {
+        return GetError(e);
+      } else {
+        return GetError(UnknownException("Unexpected error: $e", null, null));
+      }
+    }
+  }
+
+  @override
+  Future<SetResponse> set(String cacheName, Value key, Value value,
+      {Duration? ttl}) async {
+    var request = SetRequest_();
+    request.cacheKey = key.toBinary();
+    request.cacheBody = value.toBinary();
+    request.ttlMilliseconds = (ttl != null
+        ? ttl.inMilliseconds
+        : _defaultTtl.inMilliseconds) as Int64;
+    try {
+      await _client.set(request,
+          options: CallOptions(metadata: {
+            'cacheName': cacheName,
+          }));
+      return SetSuccess();
+    } catch (e) {
+      if (e is SdkException) {
+        return SetError(e);
+      } else {
+        return SetError(UnknownException("Unexpected error: $e", null, null));
+      }
+    }
+  }
+}

lib/src/messages/responses/cache/data/scalar/get_response.dart

@@ -0,0 +1,20 @@
+import 'dart:convert';
+
+import 'package:client_sdk_dart/src/messages/responses/responses_base.dart';
+
+sealed class GetResponse {}
+
+class GetMiss implements GetResponse {}
+
+class GetError extends ErrorResponseBase implements GetResponse {
+  GetError(super.exception);
+}
+
+class GetHit implements GetResponse {
+  GetHit(this._value);
+
+  final List<int> _value;
+
+  String get value => utf8.decode(_value);
+  List<int> get binaryValue => _value;
+}

lib/src/messages/responses/cache/data/scalar/set_response.dart

@@ -0,0 +1,9 @@
+import 'package:client_sdk_dart/src/messages/responses/responses_base.dart';
+
+sealed class SetResponse {}
+
+class SetSuccess implements SetResponse {}
+
+class SetError extends ErrorResponseBase implements SetResponse {
+  SetError(super.exception);
+}

lib/src/messages/values.dart

@@ -1,13 +1,38 @@
-sealed class Value {}
+import 'dart:convert';
+
+sealed class Value {
+  List<int> toBinary();
+  String toUtf8();
+}
 
 class StringValue implements Value {
   final String _value;
   StringValue(String v) : _value = v;
   String get value => _value;
+
+  @override
+  toBinary() {
+    return utf8.encode(_value);
+  }
+
+  @override
+  toUtf8() {
+    return _value;
+  }
 }
 
 class BinaryValue implements Value {
   final List<int> _value;
   BinaryValue(List<int> v) : _value = v;
   List<int> get value => _value;
+
+  @override
+  List<int> toBinary() {
+    return _value;
+  }
+
+  @override
+  String toUtf8() {
+    return utf8.decode(_value);
+  }
 }

pubspec.yaml

@@ -8,6 +8,7 @@ environment:
 
 # Add regular dependencies here.
 dependencies:
+  fixnum: ^1.1.0
   grpc: ^3.2.4
   jwt_decoder: ^2.0.1
   logging: ^1.2.0