fix(client): read all tuples (#32)

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## Description
<!-- Provide a detailed description of the changes -->

## References
<!-- Provide a list of any applicable references here (Github Issue,
[OpenFGA RFC](https://github.com/openfga/rfcs), other PRs, etc..) -->

- Closes #31

## Review Checklist
- [ ] I have clicked on ["allow edits by
maintainers"](https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/allowing-changes-to-a-pull-request-branch-created-from-a-fork).
- [ ] I have added documentation for new/changed functionality in this
PR or in a PR to [openfga.dev](https://github.com/openfga/openfga.dev)
[Provide a link to any relevant PRs in the references section above]
- [ ] The correct base branch is being used, if not `main`
- [ ] I have added tests to validate that the change in functionality is
working as expected

src/OpenFga.Sdk.Test/Api/OpenFgaApiTests.cs

@@ -1373,6 +1373,50 @@ public async Task ReadTest() {
             Assert.Equal(response, expectedResponse);
         }
 
+        /// <summary>
+        /// Test Read With Empty Parameters
+        /// </summary>
+        [Fact]
+        public async Task ReadEmptyTest() {
+            var mockHandler = new Mock<HttpMessageHandler>(MockBehavior.Strict);
+            var expectedResponse = new ReadResponse() {
+                Tuples = new List<Model.Tuple>() {
+                                new(new TupleKey("document:roadmap", "viewer", "user:81684243-9356-4421-8fbf-a4f8d36aa31b"), DateTime.Now)
+                            }
+            };
+            mockHandler.Protected()
+                .Setup<Task<HttpResponseMessage>>(
+                    "SendAsync",
+                    ItExpr.Is<HttpRequestMessage>(req =>
+                        req.RequestUri == new Uri($"{_config.BasePath}/stores/{_config.StoreId}/read") &&
+                        req.Method == HttpMethod.Post),
+                    ItExpr.IsAny<CancellationToken>()
+                )
+                .ReturnsAsync(new HttpResponseMessage() {
+                    StatusCode = HttpStatusCode.OK,
+                    Content = Utils.CreateJsonStringContent(expectedResponse),
+                });
+
+            var httpClient = new HttpClient(mockHandler.Object);
+            var openFgaApi = new OpenFgaApi(_config, httpClient);
+
+            var body = new ReadRequest { };
+            var response = await openFgaApi.Read(body);
+
+            mockHandler.Protected().Verify(
+                "SendAsync",
+                Times.Exactly(1),
+                ItExpr.Is<HttpRequestMessage>(req =>
+                    req.RequestUri == new Uri($"{_config.BasePath}/stores/{_config.StoreId}/read") &&
+                    req.Method == HttpMethod.Post),
+                ItExpr.IsAny<CancellationToken>()
+            );
+
+            Assert.IsType<ReadResponse>(response);
+            Assert.Single(response.Tuples);
+            Assert.Equal(response, expectedResponse);
+        }
+
         /// <summary>
         /// Test ReadChanges
         /// </summary>

src/OpenFga.Sdk.Test/Client/OpenFgaClientTests.cs

@@ -608,7 +608,8 @@ public async Task ReadTest() {
                 "SendAsync",
                 ItExpr.Is<HttpRequestMessage>(req =>
                     req.RequestUri == new Uri($"{_config.BasePath}/stores/{_config.StoreId}/read") &&
-                    req.Method == HttpMethod.Post),
+                    req.Method == HttpMethod.Post &&
+                    req.Content.ReadAsStringAsync().Result.Contains("tuple")),
                 ItExpr.IsAny<CancellationToken>()
             )
             .ReturnsAsync(new HttpResponseMessage() {
@@ -632,7 +633,56 @@ public async Task ReadTest() {
             Times.Exactly(1),
             ItExpr.Is<HttpRequestMessage>(req =>
                 req.RequestUri == new Uri($"{_config.BasePath}/stores/{_config.StoreId}/read") &&
-                req.Method == HttpMethod.Post),
+                req.Method == HttpMethod.Post &&
+                req.Content.ReadAsStringAsync().Result.Contains("tuple")),
+            ItExpr.IsAny<CancellationToken>()
+        );
+
+        Assert.IsType<ReadResponse>(response);
+        Assert.Single(response.Tuples);
+        Assert.Equal(response, expectedResponse);
+    }
+
+    /// <summary>
+    /// Test Read with Empty Body
+    /// </summary>
+    [Fact]
+    public async Task ReadEmptyTest() {
+        var mockHandler = new Mock<HttpMessageHandler>(MockBehavior.Strict);
+        var expectedResponse = new ReadResponse() {
+            Tuples = new List<Model.Tuple>() {
+                new(new TupleKey("document:roadmap", "viewer", "user:81684243-9356-4421-8fbf-a4f8d36aa31b"),
+                    DateTime.Now)
+            }
+        };
+        mockHandler.Protected()
+            .Setup<Task<HttpResponseMessage>>(
+                "SendAsync",
+                ItExpr.Is<HttpRequestMessage>(req =>
+                    req.RequestUri == new Uri($"{_config.BasePath}/stores/{_config.StoreId}/read") &&
+                    req.Method == HttpMethod.Post &&
+                    !req.Content.ReadAsStringAsync().Result.Contains("tuple")),
+                ItExpr.IsAny<CancellationToken>()
+            )
+            .ReturnsAsync(new HttpResponseMessage() {
+                StatusCode = HttpStatusCode.OK,
+                Content = Utils.CreateJsonStringContent(expectedResponse),
+            });
+
+        var httpClient = new HttpClient(mockHandler.Object);
+        var fgaClient = new OpenFgaClient(_config, httpClient);
+
+        var body = new ClientReadRequest() { };
+        var options = new ClientReadOptions { };
+        var response = await fgaClient.Read(body, options);
+
+        mockHandler.Protected().Verify(
+            "SendAsync",
+            Times.Exactly(1),
+            ItExpr.Is<HttpRequestMessage>(req =>
+                req.RequestUri == new Uri($"{_config.BasePath}/stores/{_config.StoreId}/read") &&
+                req.Method == HttpMethod.Post &&
+                !req.Content.ReadAsStringAsync().Result.Contains("tuple")),
             ItExpr.IsAny<CancellationToken>()
         );
 

src/OpenFga.Sdk/Client/Client.cs

@@ -148,13 +148,18 @@ public async Task<ReadChangesResponse> ReadChanges(ClientReadChangesRequest body
      * Read - Read tuples previously written to the store (does not evaluate)
      */
     public async Task<ReadResponse> Read(ClientReadRequest body, IClientReadOptions? options = default,
-        CancellationToken cancellationToken = default) =>
-        await api.Read(
+        CancellationToken cancellationToken = default) {
+        TupleKey tupleKey = null;
+        if (body != null && (body.User != null || body.Relation != null || body.Object != null)) {
+            tupleKey = body;
+        }
+        return await api.Read(
             new ReadRequest {
-                TupleKey = body,
+                TupleKey = tupleKey,
                 PageSize = options?.PageSize,
                 ContinuationToken = options?.ContinuationToken
             }, cancellationToken);
+    }
 
     /**
      * Write - Create or delete relationship tuples