Fixed bug in output stream that was causing large files to be written incorrectly.

Author: voidmain

Diff for: src/main/java/io/fusionauth/http/io/ChunkedOutputStream.java

@@ -82,8 +82,8 @@ public void write(byte[] b) throws IOException {
   public void write(byte[] b, int offset, int length) throws IOException {
     int index = offset;
     while (index < length) {
-      int wrote = Math.min(buffer.length - bufferIndex, length);
-      System.arraycopy(b, 0, buffer, bufferIndex, wrote);
+      int wrote = Math.min(buffer.length - bufferIndex, length - index);
+      System.arraycopy(b, index, buffer, bufferIndex, wrote);
       bufferIndex += wrote;
       index += wrote;
 

Diff for: src/test/java/io/fusionauth/http/CoreTest.java

@@ -26,6 +26,8 @@
 import java.net.http.HttpRequest.BodyPublishers;
 import java.net.http.HttpResponse.BodySubscribers;
 import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Paths;
 import java.security.SecureRandom;
 import java.security.cert.Certificate;
 import java.time.Duration;
@@ -319,6 +321,35 @@ public void keepAliveTimeout() {
     }
   }
 
+  @Test(dataProvider = "schemes")
+  public void largeCSS(String scheme) throws Exception {
+    var css = Files.readString(Paths.get("src/test/resources/fontawesome-6.0.0.min.css"), StandardCharsets.UTF_8);
+
+    HTTPHandler handler = (req, res) -> {
+      res.setStatus(200);
+
+      try {
+        var out = res.getOutputStream();
+        out.write(css.getBytes(StandardCharsets.UTF_8));
+        out.close();
+      } catch (Throwable t) {
+        System.out.println(t);
+      }
+    };
+
+    try (var client = makeClient(scheme, null); var ignore = makeServer(scheme, handler).start()) {
+      URI uri = makeURI(scheme, "");
+      HttpRequest request = HttpRequest.newBuilder()
+                                       .uri(uri)
+                                       .GET()
+                                       .build();
+
+      var response = client.send(request, r -> BodySubscribers.ofString(StandardCharsets.UTF_8));
+      assertEquals(response.statusCode(), 200);
+      assertEquals(response.body(), css);
+    }
+  }
+
   @Test
   public void logger() {
     // Test replacement values and ensure we are handling special regex characters.