Added support to specify Custom Hop-By-Hop Headers

src/main/java/io/vertx/httpproxy/ProxyOptions.java

@@ -4,9 +4,20 @@
 import io.vertx.codegen.json.annotations.JsonGen;
 import io.vertx.core.json.JsonObject;
 import io.vertx.httpproxy.cache.CacheOptions;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Set;
+
+import static io.vertx.core.http.HttpHeaders.CONNECTION;
+import static io.vertx.core.http.HttpHeaders.KEEP_ALIVE;
+import static io.vertx.core.http.HttpHeaders.PROXY_AUTHENTICATE;
+import static io.vertx.core.http.HttpHeaders.PROXY_AUTHORIZATION;
+import static io.vertx.core.http.HttpHeaders.TRANSFER_ENCODING;
+import static io.vertx.core.http.HttpHeaders.UPGRADE;
 
 /**
  * Proxy options.
+ *
  */
 @DataObject
 @JsonGen(publicConverter = false)
@@ -17,15 +28,28 @@ public class ProxyOptions {
    */
   public static final boolean DEFAULT_SUPPORT_WEBSOCKET = true;
 
+  public static final Set<String> DEFAULT_HOP_BY_HOP_HEADERS = new HashSet<>(Arrays.asList(
+    CONNECTION.toString(),
+    KEEP_ALIVE.toString(),
+    PROXY_AUTHENTICATE.toString(),
+    PROXY_AUTHORIZATION.toString(),
+    TRANSFER_ENCODING.toString(),
+    UPGRADE.toString(),
+    "te",
+    "trailer"
+  ));
+
   private CacheOptions cacheOptions;
   private boolean supportWebSocket;
+  private Set<String> customHopHeaders;
 
   public ProxyOptions(JsonObject json) {
     ProxyOptionsConverter.fromJson(json, this);
   }
 
   public ProxyOptions() {
     supportWebSocket = DEFAULT_SUPPORT_WEBSOCKET;
+    customHopHeaders = DEFAULT_HOP_BY_HOP_HEADERS;
   }
 
   /**
@@ -66,6 +90,42 @@ public ProxyOptions setSupportWebSocket(boolean supportWebSocket) {
     return this;
   }
 
+  /**
+   * @return custom hop-by-hop headers
+   */
+  public Set<String> getCustomHopHeaders() {
+    return customHopHeaders;
+  }
+
+  /**
+   * Sets custom hop-by-hop headers, overriding the default {@code DEFAULT_HOP_BY_HOP_HEADERS} headers.
+   * <p>
+   * <b>Warning:</b> Please read the following specification before removing or modifying
+   * any hop-by-hop header:
+   * <a href="https://datatracker.ietf.org/doc/html/rfc2616#section-13.5.1">
+   * RFC 2616, Section 13.5.1
+   * </a>
+   * </p>
+   *
+   * @param customHopHeaders the list of hop-by-hop headers to set
+   * @return a reference to this, so the API can be used fluently
+   */
+  public ProxyOptions setCustomHopHeaders(Set<String> customHopHeaders){
+    this.customHopHeaders = new HashSet<String>(customHopHeaders);
+    return this;
+  }
+
+  /**
+   * Add a custom hop-by-hop header
+   *
+   * @param customHopHeader a custom hop-by-hop header
+   * @return a reference to this, so the API can be used fluently
+   */
+  public ProxyOptions addCustomHopHeader(String customHopHeader) {
+    this.customHopHeaders.add(customHopHeader);
+    return this;
+  }
+
   @Override
   public String toString() {
     return toJson().toString();

src/main/java/io/vertx/httpproxy/ProxyRequest.java

@@ -21,6 +21,7 @@
 import io.vertx.core.http.HttpVersion;
 import io.vertx.core.net.HostAndPort;
 import io.vertx.httpproxy.impl.ProxiedRequest;
+import java.util.Set;
 
 /**
  *
@@ -178,4 +179,20 @@ default Future<Void> proxy(HttpClientRequest request) {
    */
   ProxyResponse response();
 
+  /**
+   * Set Custom Hop-By-Hop Headers
+   *
+   * @return a reference to this, so the API can be used fluently
+   */
+  @Fluent
+  ProxyRequest setCustomHopHeaders(Set<String> customHopHeaders);
+
+  /**
+   * Add Custom Hop-By-Hop Header
+   *
+   * @return a reference to this, so the API can be used fluently
+   */
+  @Fluent
+  ProxyRequest addCustomHopHeader(String customHopHeader);
+
 }

src/main/java/io/vertx/httpproxy/impl/ProxiedRequest.java

@@ -23,35 +23,22 @@
 import io.vertx.core.net.HostAndPort;
 import io.vertx.core.streams.Pipe;
 import io.vertx.httpproxy.Body;
-import io.vertx.httpproxy.MediaType;
 import io.vertx.httpproxy.ProxyRequest;
 import io.vertx.httpproxy.ProxyResponse;
-
+import io.vertx.httpproxy.ProxyOptions;
 import java.util.Map;
 import java.util.Objects;
-
-import static io.vertx.core.http.HttpHeaders.CONNECTION;
+import java.util.HashSet;
+import java.util.Set;
 import static io.vertx.core.http.HttpHeaders.CONTENT_LENGTH;
-import static io.vertx.core.http.HttpHeaders.KEEP_ALIVE;
-import static io.vertx.core.http.HttpHeaders.PROXY_AUTHENTICATE;
-import static io.vertx.core.http.HttpHeaders.PROXY_AUTHORIZATION;
-import static io.vertx.core.http.HttpHeaders.TRANSFER_ENCODING;
-import static io.vertx.core.http.HttpHeaders.UPGRADE;
 
 public class ProxiedRequest implements ProxyRequest {
 
   private static final CharSequence X_FORWARDED_HOST = HttpHeaders.createOptimized("x-forwarded-host");
 
-  private static final MultiMap HOP_BY_HOP_HEADERS = MultiMap.caseInsensitiveMultiMap()
-    .add(CONNECTION, "whatever")
-    .add(KEEP_ALIVE, "whatever")
-    .add(PROXY_AUTHENTICATE, "whatever")
-    .add(PROXY_AUTHORIZATION, "whatever")
-    .add("te", "whatever")
-    .add("trailer", "whatever")
-    .add(TRANSFER_ENCODING, "whatever")
-    .add(UPGRADE, "whatever");
+  private static final Set<String> DEFAULT_HOP_BY_HOP_HEADERS = new HashSet<>(ProxyOptions.DEFAULT_HOP_BY_HOP_HEADERS);
 
+  private Set<String> HOP_BY_HOP_HEADERS;
   final ContextInternal context;
   private HttpMethod method;
   private final HttpVersion version;
@@ -88,6 +75,7 @@ public ProxiedRequest(HttpServerRequest proxiedRequest) {
     this.proxiedRequest = proxiedRequest;
     this.context = ((HttpServerRequestInternal) proxiedRequest).context();
     this.authority = null; // null is used as a signal to indicate an unchanged authority
+    this.HOP_BY_HOP_HEADERS = DEFAULT_HOP_BY_HOP_HEADERS;
   }
 
   @Override
@@ -173,7 +161,7 @@ Future<ProxyResponse> sendRequest() {
     for (Map.Entry<String, String> header : headers) {
       String name = header.getKey();
       String value = header.getValue();
-      if (!HOP_BY_HOP_HEADERS.contains(name) && !name.equalsIgnoreCase(HttpHeaders.HOST.toString())) {
+      if (!HOP_BY_HOP_HEADERS.contains(name)) {
         request.headers().add(name, value);
       }
     }
@@ -241,4 +229,16 @@ public Future<ProxyResponse> send(HttpClientRequest request) {
     this.request = request;
     return sendRequest();
   }
+
+  @Override
+  public ProxyRequest setCustomHopHeaders(Set<String> customHopHeaders) {
+    this.HOP_BY_HOP_HEADERS = new HashSet<>(customHopHeaders);
+    return this;
+  }
+
+  @Override
+  public ProxyRequest addCustomHopHeader(String customHopHeader) {
+    this.HOP_BY_HOP_HEADERS.add(customHopHeader);
+    return this;
+  }
 }

src/main/java/io/vertx/httpproxy/impl/ReverseProxy.java

@@ -24,9 +24,7 @@
 import io.vertx.httpproxy.*;
 import io.vertx.httpproxy.cache.CacheOptions;
 import io.vertx.httpproxy.spi.cache.Cache;
-
 import java.util.*;
-
 import static io.vertx.core.http.HttpHeaders.CONNECTION;
 import static io.vertx.core.http.HttpHeaders.HOST;
 import static io.vertx.core.http.HttpHeaders.UPGRADE;
@@ -38,6 +36,7 @@ public class ReverseProxy implements HttpProxy {
   private final boolean supportWebSocket;
   private OriginRequestProvider originRequestProvider = (pc) -> Future.failedFuture("No origin available");
   private final List<ProxyInterceptorEntry> interceptors = new ArrayList<>();
+  private final Set<String> hopByHopHeaders;
 
   public ReverseProxy(ProxyOptions options, HttpClient client) {
     CacheOptions cacheOptions = options.getCacheOptions();
@@ -47,6 +46,7 @@ public ReverseProxy(ProxyOptions options, HttpClient client) {
     }
     this.client = client;
     this.supportWebSocket = options.getSupportWebSocket();
+    this.hopByHopHeaders = options.getCustomHopHeaders();
   }
 
   public Cache newCache(CacheOptions options, Vertx vertx) {
@@ -75,6 +75,8 @@ public HttpProxy addInterceptor(ProxyInterceptor interceptor, boolean supportsWe
   public void handle(HttpServerRequest request) {
     ProxyRequest proxyRequest = ProxyRequest.reverseProxy(request);
 
+    proxyRequest.setCustomHopHeaders(hopByHopHeaders);
+
     // Encoding sanity check
     Boolean chunked = HttpUtils.isChunked(request.headers());
     if (chunked == null) {