fix(esg): honor the declared response charset in ReadBodyBoundedAsync with UTF-8 fallback (plan R2-06 T4)

2026-07-13 09:53:00 -04:00
parent cc94b3a68c
commit b41b3b1b31
2 changed files with 87 additions and 1 deletions
@@ -1,5 +1,6 @@
 using System.Net;
 using System.Net.Http.Headers;
+using System.Text;
 using Microsoft.Data.Sqlite;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Logging.Abstractions;
@@ -1377,4 +1378,57 @@ public class ExternalSystemClientTests

        Assert.False(delivered);
    }
+
+    [Fact]
+    public async Task Call_Latin1Charset_DecodesUsingDeclaredCharset()
+    {
+        // Arch-review R2 N4: the bounded read must honor the declared charset —
+        // UTF-8-decoding an iso-8859-1 body turns every non-ASCII byte into U+FFFD.
+        var system = new ExternalSystemDefinition("TestAPI", "https://api.example.com", "none") { Id = 1 };
+        var method = new ExternalSystemMethod("getData", "GET", "/data") { Id = 1, ExternalSystemDefinitionId = 1 };
+        StubResolution(system, method);
+        var handler = new ByteBodyHandler(
+            HttpStatusCode.OK,
+            Encoding.Latin1.GetBytes("température 25°C"),
+            "text/plain; charset=iso-8859-1");
+        _httpClientFactory.CreateClient(Arg.Any<string>()).Returns(new HttpClient(handler));
+        var client = new ExternalSystemClient(
+            _httpClientFactory, _repository, NullLogger<ExternalSystemClient>.Instance);
+
+        var result = await client.CallAsync("TestAPI", "getData");
+
+        Assert.True(result.Success);
+        Assert.Contains("température 25°C", result.ResponseJson);
+    }
+
+    [Fact]
+    public async Task Call_UnknownCharset_FallsBackToUtf8()
+    {
+        var system = new ExternalSystemDefinition("TestAPI", "https://api.example.com", "none") { Id = 1 };
+        var method = new ExternalSystemMethod("getData", "GET", "/data") { Id = 1, ExternalSystemDefinitionId = 1 };
+        StubResolution(system, method);
+        var handler = new ByteBodyHandler(
+            HttpStatusCode.OK, Encoding.UTF8.GetBytes("ok"), "text/plain; charset=not-a-charset");
+        _httpClientFactory.CreateClient(Arg.Any<string>()).Returns(new HttpClient(handler));
+        var client = new ExternalSystemClient(
+            _httpClientFactory, _repository, NullLogger<ExternalSystemClient>.Instance);
+
+        var result = await client.CallAsync("TestAPI", "getData");
+
+        Assert.True(result.Success);
+        Assert.Contains("ok", result.ResponseJson);
+    }
+
+    /// <summary>Test helper: returns a fixed byte body with an explicit Content-Type.</summary>
+    private sealed class ByteBodyHandler(
+        HttpStatusCode statusCode, byte[] body, string contentType) : HttpMessageHandler
+    {
+        protected override Task<HttpResponseMessage> SendAsync(
+            HttpRequestMessage request, CancellationToken cancellationToken)
+        {
+            var response = new HttpResponseMessage(statusCode) { Content = new ByteArrayContent(body) };
+            response.Content.Headers.ContentType = MediaTypeHeaderValue.Parse(contentType);
+            return Task.FromResult(response);
+        }
+    }
 }