Support toggling 100-continue support feature in vert.x

(cherry picked from commit b3ac19b)

docs/src/main/asciidoc/http-reference.adoc

@@ -245,6 +245,16 @@ Will include the `Cache-Control: max-age=1` header when `/paths/order` is reques
 
 include::{generated-dir}/config/quarkus-vertx-http-config-group-filter-config.adoc[leveloffset=+1, opts=optional]
 
+== Support 100-Continue in vert.x
+
+In order to support `100-continue`, the `quarkus.http.handle-100-continue-automatically` option needs to be enabled explicitly
+For additional information check https://datatracker.ietf.org/doc/html/rfc7231#section-5.1.1[100-continue= and the related
+https://vertx.io/docs/apidocs/io/vertx/core/http/HttpServerOptions.html#DEFAULT_HANDLE_100_CONTINE_AUTOMATICALLY[Vert.x documentation].
+
+[source,properties]
+----
+quarkus.http.handle-100-continue-automatically=true
+----
 
 == HTTP/2 Support
 

extensions/vertx-http/deployment/src/test/java/io/quarkus/vertx/http/HttpContinueHeaderTest.java

@@ -0,0 +1,67 @@
+package io.quarkus.vertx.http;
+
+import java.net.Socket;
+import java.net.URL;
+import java.nio.charset.StandardCharsets;
+
+import javax.enterprise.context.ApplicationScoped;
+import javax.enterprise.event.Observes;
+
+import org.jboss.shrinkwrap.api.asset.StringAsset;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+import io.quarkus.test.QuarkusUnitTest;
+import io.quarkus.test.common.http.TestHTTPResource;
+import io.vertx.core.Handler;
+import io.vertx.ext.web.Router;
+import io.vertx.ext.web.RoutingContext;
+
+public class HttpContinueHeaderTest {
+    private static final String APP_PROPS = "quarkus.http.handle-100-continue-automatically=true\n";
+
+    @RegisterExtension
+    static final QuarkusUnitTest config = new QuarkusUnitTest()
+            .withApplicationRoot((jar) -> jar
+                    .addAsResource(new StringAsset(APP_PROPS), "application.properties")
+                    .addClasses(HttpContinueHeaderTest.BeanRegisteringRouteUsingObserves.class));
+
+    @TestHTTPResource
+    URL uri;
+
+    @Test
+    public void testConnection() throws Exception {
+        try (Socket one = new Socket(uri.getHost(), uri.getPort())) {
+            one.getOutputStream().write("GET /hello HTTP/1.1\r\nExpect: 100-continue\r\nHost: localhost\r\n\r\n"
+                    .getBytes(StandardCharsets.UTF_8));
+
+            StringBuilder sb = new StringBuilder();
+            byte[] data = new byte[1024];
+            int j;
+            while (!sb.toString().endsWith("hello")) {
+                j = one.getInputStream().read(data);
+                if (j == -1) {
+                    Assertions.fail("Did not read full HTTP response");
+                }
+                sb.append(new String(data, 0, j, StandardCharsets.US_ASCII));
+            }
+            Assertions.assertTrue(sb.toString().contains("HTTP/1.1 100 Continue"));
+            Assertions.assertTrue(sb.toString().contains("HTTP/1.1 200 OK"));
+        }
+    }
+
+    @ApplicationScoped
+    static class BeanRegisteringRouteUsingObserves {
+
+        public void register(@Observes Router router) {
+            router.route("/hello").handler(new Handler<RoutingContext>() {
+                @Override
+                public void handle(RoutingContext event) {
+                    event.end("hello");
+                }
+            });
+
+        }
+    }
+}

extensions/vertx-http/runtime/src/main/java/io/quarkus/vertx/http/runtime/HttpConfiguration.java

@@ -91,6 +91,13 @@ public class HttpConfiguration {
      */
     public ServerSslConfig ssl;
 
+    /**
+     * When set to {@code true}, the HTTP server automatically sends `100 CONTINUE`
+     * response when the request expects it (with the `Expect: 100-Continue` header).
+     */
+    @ConfigItem(defaultValue = "false", name = "handle-100-continue-automatically")
+    public boolean handle100ContinueAutomatically;
+
     /**
      * The number if IO threads used to perform IO. This will be automatically set to a reasonable value based on
      * the number of CPU cores if it is not provided. If this is set to a higher value than the number of Vert.x event

extensions/vertx-http/runtime/src/main/java/io/quarkus/vertx/http/runtime/VertxHttpRecorder.java

@@ -861,6 +861,7 @@ private static void applyCommonOptions(HttpServerOptions httpServerOptions,
         }
         httpServerOptions.setDecompressionSupported(buildTimeConfig.enableDecompression);
         httpServerOptions.setMaxInitialLineLength(httpConfiguration.limits.maxInitialLineLength);
+        httpServerOptions.setHandle100ContinueAutomatically(httpConfiguration.handle100ContinueAutomatically);
     }
 
     private static KeyStoreOptions createKeyStoreOptions(Path path, String password, Optional<String> fileType,