Add chat-ui-htmx module: streaming chat page on Spring AI 2.0.2 with htmx and its SSE extension (vendored), MessageChatMemoryAdvisor keyed by the HTTP session, a Stop button, and the traps measured: EventSource strips one leading space per data line, model text must be HTML-escaped, a cancelled stream left the upstream connection open in 7 of 8 runs until an OkHttp interceptor calls Call.cancel (8 of 8 closed after), and the SDK push source ignores back-pressure (limitRate changes only the demand; a bounded buffer works). The model is a stub OpenAI-compatible SSE server written for the module; no real provider was run.

Co-Authored-By: Claude Sonnet 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_017ic4b6Kg9RWSTJzyz6KP9X
2026-10-31 04:02:56 +00:00
parent c97bcf9adf
commit 68da642f9a
35 changed files with 1571 additions and 0 deletions
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+package com.ankurm.chatui;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import com.ankurm.chatui.stub.OpenAiStubServer;
+import okhttp3.MediaType;
+import okhttp3.OkHttpClient;
+import okhttp3.Request;
+import okhttp3.RequestBody;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+/**
+ * No Spring AI, no SDK: plain OkHttp 4.12 against the stub. A reader thread is blocked reading the
+ * SSE body; another thread then closes the response, or cancels the call. Which one closes the socket?
+ */
+class OkHttpCloseReproTest {
+
+    @BeforeAll
+    static void stub() {
+        StubSupport.ensureStarted();
+    }
+
+    int run(boolean cancelInsteadOfClose, Transcript t) throws Exception {
+        var http = new OkHttpClient();
+        int closed = 0;
+        for (int i = 0; i < 10; i++) {
+            long[] before = OpenAiStubServer.counters();
+            var req = new Request.Builder().url("http://localhost:" + StubSupport.PORT + "/v1/chat/completions")
+                    .post(RequestBody.create("{\"model\":\"m\",\"stream\":true,\"messages\":[{\"role\":\"user\","
+                            + "\"content\":\"count 60\"}]}", MediaType.get("application/json"))).build();
+            var call = http.newCall(req);
+            var response = call.execute();
+            var source = response.body().source();
+            var reader = new Thread(() -> {
+                try {
+                    while (source.readUtf8Line() != null) {
+                        // keep reading
+                    }
+                } catch (Exception ignored) {
+                    // closed under us
+                }
+            });
+            reader.start();
+            Thread.sleep(150);
+            try {
+                if (cancelInsteadOfClose) {
+                    call.cancel();
+                } else {
+                    response.close();
+                }
+            } catch (RuntimeException e) {
+                if (i == 0) {
+                    t.line("  response.close() threw: " + e);
+                }
+            }
+            Thread.sleep(500);
+            if (OpenAiStubServer.counters()[3] - before[3] == 1) {
+                closed++;
+            }
+            reader.join(2000);
+        }
+        return closed;
+    }
+
+    @Test
+    void closeFromAnotherThreadLeaksCancelDoesNot() throws Exception {
+        var t = new Transcript("05-okhttp-close-vs-cancel.txt");
+        t.line("plain OkHttp 4.12.0, 10 runs each, stub streaming 60 chunks at 20 ms, reader thread blocked in a read");
+        int viaClose = run(false, t);
+        t.line("response.close() from another thread: upstream connection closed in " + viaClose + " of 10 runs");
+        int viaCancel = run(true, t);
+        t.line("call.cancel()     from another thread: upstream connection closed in " + viaCancel + " of 10 runs");
+        assertThat(viaCancel).isEqualTo(10);
+        assertThat(viaClose).isLessThanOrEqualTo(2);
+    }
+}