Add helper method to determine if request can be upgraded to websocket.

Vert.x Web And Vert.x HTTP Proxy have similar code.
This method covers all cases and can be reused.

Signed-off-by: Thomas Segismont <tsegismont@gmail.com>

src/main/java/io/vertx/core/http/impl/HttpUtils.java

@@ -1016,4 +1016,24 @@ public static boolean isValidHostAuthority(String host) {
     int len = host.length();
     return HostAndPortImpl.parseHost(host, 0, len) == len;
   }
+
+  public static boolean canUpgradeToWebSocket(HttpServerRequest req) {
+    if (req.version() != io.vertx.core.http.HttpVersion.HTTP_1_1) {
+      return false;
+    }
+    if (req.method() != io.vertx.core.http.HttpMethod.GET) {
+      return false;
+    }
+    MultiMap headers = req.headers();
+    for (String connection : headers.getAll(io.vertx.core.http.HttpHeaders.CONNECTION)) {
+      if (connection.toLowerCase().contains(io.vertx.core.http.HttpHeaders.UPGRADE)) {
+        for (String upgrade : headers.getAll(io.vertx.core.http.HttpHeaders.UPGRADE)) {
+          if (upgrade.toLowerCase().contains(io.vertx.core.http.HttpHeaders.WEBSOCKET)) {
+            return true;
+          }
+        }
+      }
+    }
+    return false;
+  }
 }

src/test/java/io/vertx/core/http/Http1xTest.java

@@ -45,10 +45,7 @@
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicReference;
-import java.util.function.BiConsumer;
-import java.util.function.Consumer;
-import java.util.function.Function;
-import java.util.function.LongConsumer;
+import java.util.function.*;
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 import java.util.stream.Stream;
@@ -5310,4 +5307,61 @@ public void testMissingHostHeader() throws Exception {
     }));
     await();
   }
+
+  @Test
+  public void testCanUpgradeToWebSocket() throws Exception {
+    UnaryOperator<RequestOptions> config = ro -> ro.setMethod(HttpMethod.GET)
+      .putHeader(HttpHeaders.CONNECTION, HttpHeaders.UPGRADE)
+      .putHeader(HttpHeaders.UPGRADE, HttpHeaders.WEBSOCKET);
+    doTestCanUpgradeToWebSocket(config, true);
+  }
+
+  @Test
+  public void testCanUpgradeToWebSocketFirefox() throws Exception {
+    UnaryOperator<RequestOptions> config = ro -> ro.setMethod(HttpMethod.GET)
+      .putHeader(HttpHeaders.CONNECTION, HttpHeaders.KEEP_ALIVE + ", " + HttpHeaders.UPGRADE)
+      .putHeader(HttpHeaders.UPGRADE, HttpHeaders.WEBSOCKET);
+    doTestCanUpgradeToWebSocket(config, true);
+  }
+
+  @Test
+  public void testCannotUpgradePostRequestToWebSocket() throws Exception {
+    UnaryOperator<RequestOptions> config = ro -> ro.setMethod(HttpMethod.POST)
+      .putHeader(HttpHeaders.CONNECTION, HttpHeaders.UPGRADE)
+      .putHeader(HttpHeaders.UPGRADE, HttpHeaders.WEBSOCKET);
+    doTestCanUpgradeToWebSocket(config, false);
+  }
+
+  @Test
+  public void testCannotUpgradeToWebSocketIfConnectionHeaderIsMissing() throws Exception {
+    UnaryOperator<RequestOptions> config = ro -> ro.setMethod(HttpMethod.GET)
+      .putHeader(HttpHeaders.UPGRADE, HttpHeaders.WEBSOCKET);
+    doTestCanUpgradeToWebSocket(config, false);
+  }
+
+  @Test
+  public void testCannotUpgradeToWebSocketIfUpgradeDoesNotContainWebsocket() throws Exception {
+    UnaryOperator<RequestOptions> config = ro -> ro.setMethod(HttpMethod.GET)
+      .putHeader(HttpHeaders.CONNECTION, HttpHeaders.UPGRADE)
+      .putHeader(HttpHeaders.UPGRADE, "foo");
+    doTestCanUpgradeToWebSocket(config, false);
+  }
+
+  private void doTestCanUpgradeToWebSocket(UnaryOperator<RequestOptions> config, boolean shouldSucceed) throws Exception {
+    server.requestHandler(req -> {
+      HttpServerResponse serverResponse = req.response();
+      int statusCode = HttpUtils.canUpgradeToWebSocket(req) ? 200 : 500;
+      serverResponse.setStatusCode(statusCode);
+      serverResponse.end();
+    });
+    startServer(testAddress);
+    client.request(config.apply(new RequestOptions(requestOptions))).onComplete(onSuccess(req -> {
+      req.response().onComplete(onSuccess(resp -> {
+        assertEquals(shouldSucceed ? 200 : 500, resp.statusCode());
+        testComplete();
+      }));
+      req.send();
+    }));
+    await();
+  }
 }