After calling the user function, flush either the OutputStream or the Writer as appropriate. Calling getWriter().flush() will fail if getOutputStream() has previously been called. The method ServletResponse.flushBuffer() might be expected to work here but it did not.

Fixes #15.

PiperOrigin-RevId: 296899120

Author: eamonnmcmanus

invoker/core/src/main/java/com/google/cloud/functions/invoker/NewHttpFunctionExecutor.java

@@ -72,7 +72,13 @@ public void service(HttpServletRequest req, HttpServletResponse res) {
       res.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
     } finally {
       try {
-        respImpl.getWriter().flush();
+        // Shouldn't HttpServletResponse.flushBuffer() work here? But it doesn't. So we have to
+        // flush whichever of getWriter() or getOutputStream() works.
+        try {
+          respImpl.getWriter().flush();
+        } catch (IllegalStateException e) {
+          respImpl.getOutputStream().flush();
+        }
       } catch (IOException e) {
         // Too bad, can't flush.
       }

invoker/core/src/test/java/com/google/cloud/functions/invoker/IntegrationTest.java

@@ -112,7 +112,6 @@ private static CloudEventImpl<Map<String, Object>> sampleCloudEvent(File snoopFi
         .withData(ImmutableMap.of("a", 2, "b", 3, "targetFile", snoopFile.toString()))
         .withTime(ZonedDateTime.of(2018, 4, 5, 17, 31, 0, 0, ZoneOffset.UTC))
         .build();
-
   }
 
   private static int serverPort;
@@ -146,6 +145,8 @@ abstract static class TestCase {
 
     abstract Optional<String> expectedJsonString();
 
+    abstract Optional<String> expectedContentType();
+
     abstract String httpContentType();
 
     abstract ImmutableMap<String, String> httpHeaders();
@@ -175,6 +176,8 @@ abstract static class Builder {
 
       abstract Builder setExpectedResponseText(Optional<String> x);
 
+      abstract Builder setExpectedContentType(String x);
+
       abstract Builder setExpectedJsonString(String x);
 
       abstract Builder setHttpContentType(String x);
@@ -238,7 +241,17 @@ public void newEcho() throws Exception {
     testHttpFunction(
         fullTarget("NewEcho"),
         ImmutableList.of(
-            TestCase.builder().setRequestText(testText).setExpectedResponseText(testText).build()));
+            TestCase.builder()
+                .setRequestText(testText)
+                .setExpectedResponseText(testText)
+                .setExpectedContentType("text/plain")
+                .build(),
+            TestCase.builder()
+                .setHttpContentType("application/octet-stream")
+                .setRequestText(testText)
+                .setExpectedResponseText(testText)
+                .setExpectedContentType("application/octet-stream")
+                .build()));
   }
 
   @Test
@@ -462,6 +475,8 @@ private void testFunction(
             .that(response.getStatus()).isEqualTo(testCase.expectedResponseCode());
         testCase.expectedResponseText()
             .ifPresent(text -> expect.that(response.getContentAsString()).isEqualTo(text));
+        testCase.expectedContentType()
+            .ifPresent(type -> expect.that(response.getMediaType()).isEqualTo(type));
         if (testCase.snoopFile().isPresent()) {
           checkSnoopFile(testCase.snoopFile().get(), testCase.expectedJsonString().get());
         }

invoker/core/src/test/java/com/google/cloud/functions/invoker/testfunctions/NewEcho.java

@@ -3,14 +3,27 @@
 import com.google.cloud.functions.HttpFunction;
 import com.google.cloud.functions.HttpRequest;
 import com.google.cloud.functions.HttpResponse;
+import java.io.InputStream;
+import java.io.OutputStream;
 import java.util.stream.Collectors;
 
 public class NewEcho implements HttpFunction {
   @Override
   public void service(HttpRequest request, HttpResponse response) throws Exception {
-    String body = request.getReader().lines().collect(Collectors.joining("\n")) + "\n";
-    response.setContentType("text/plain");
-    response.getWriter().write(body);
-    response.getWriter().flush();
+    boolean binary = "application/octet-stream".equals(request.getContentType().orElse(null));
+    if (binary) {
+      response.setContentType("application/octet-stream");
+      byte[] buf = new byte[1024];
+      InputStream in = request.getInputStream();
+      OutputStream out = response.getOutputStream();
+      int n;
+      while ((n = in.read(buf)) > 0) {
+        out.write(buf, 0, n);
+      }
+    } else {
+      String body = request.getReader().lines().collect(Collectors.joining("\n")) + "\n";
+      response.setContentType("text/plain");
+      response.getWriter().write(body);
+    }
   }
 }