improve code

Author: arturobernalg

httpclient5/src/main/java/org/apache/hc/client5/http/config/RequestConfig.java

@@ -34,6 +34,7 @@
 import org.apache.hc.core5.annotation.Contract;
 import org.apache.hc.core5.annotation.ThreadingBehavior;
 import org.apache.hc.core5.http.HttpHost;
+import org.apache.hc.core5.http2.priority.PriorityValue;
 import org.apache.hc.core5.util.Args;
 import org.apache.hc.core5.util.TimeValue;
 import org.apache.hc.core5.util.Timeout;
@@ -69,13 +70,18 @@ public class RequestConfig implements Cloneable {
 
     private final ExpectContinueTrigger expectContinueTrigger;
 
+    /**
+     * HTTP/2 Priority header value to emit when using H2+. Null means “don’t emit”.
+     */
+    private final PriorityValue h2Priority;
+
     /**
      * Intended for CDI compatibility
     */
     protected RequestConfig() {
         this(false, null, null, false, false, 0, false, null, null,
                 DEFAULT_CONNECTION_REQUEST_TIMEOUT, null, null, DEFAULT_CONN_KEEP_ALIVE, false, false, false, null,
-                ExpectContinueTrigger.ALWAYS);
+                ExpectContinueTrigger.ALWAYS, null);
     }
 
     RequestConfig(
@@ -96,7 +102,8 @@ protected RequestConfig() {
             final boolean hardCancellationEnabled,
             final boolean protocolUpgradeEnabled,
             final Path unixDomainSocket,
-            final ExpectContinueTrigger expectContinueTrigger) {
+            final ExpectContinueTrigger expectContinueTrigger,
+            final PriorityValue h2Priority) {
         super();
         this.expectContinueEnabled = expectContinueEnabled;
         this.proxy = proxy;
@@ -116,6 +123,7 @@ protected RequestConfig() {
         this.protocolUpgradeEnabled = protocolUpgradeEnabled;
         this.unixDomainSocket = unixDomainSocket;
         this.expectContinueTrigger = expectContinueTrigger;
+        this.h2Priority = h2Priority;
     }
 
     /**
@@ -244,6 +252,14 @@ public ExpectContinueTrigger getExpectContinueTrigger() {
         return expectContinueTrigger;
     }
 
+    /**
+     * Returns the HTTP/2+ priority preference for this request or {@code null} if unset.
+     * @since 5.6
+     */
+    public PriorityValue getH2Priority() {
+        return h2Priority;
+    }
+
     @Override
     protected RequestConfig clone() throws CloneNotSupportedException {
         return (RequestConfig) super.clone();
@@ -296,7 +312,8 @@ public static RequestConfig.Builder copy(final RequestConfig config) {
             .setContentCompressionEnabled(config.isContentCompressionEnabled())
             .setHardCancellationEnabled(config.isHardCancellationEnabled())
             .setProtocolUpgradeEnabled(config.isProtocolUpgradeEnabled())
-            .setUnixDomainSocket(config.getUnixDomainSocket());
+            .setUnixDomainSocket(config.getUnixDomainSocket())
+            .setH2Priority(config.getH2Priority());
     }
 
     public static class Builder {
@@ -319,6 +336,7 @@ public static class Builder {
         private boolean protocolUpgradeEnabled;
         private Path unixDomainSocket;
         private ExpectContinueTrigger expectContinueTrigger;
+        private PriorityValue h2Priority;
 
         Builder() {
             super();
@@ -691,6 +709,15 @@ public Builder setExpectContinueTrigger(final ExpectContinueTrigger trigger) {
             return this;
         }
 
+        /**
+         * Sets HTTP/2+ request priority (RFC 9218). If {@code null}, the header is not emitted.
+         * @since 5.6
+         */
+        public Builder setH2Priority(final PriorityValue priority) {
+            this.h2Priority = priority;
+            return this;
+        }
+
         public RequestConfig build() {
             return new RequestConfig(
                     expectContinueEnabled,
@@ -710,7 +737,8 @@ public RequestConfig build() {
                     hardCancellationEnabled,
                     protocolUpgradeEnabled,
                     unixDomainSocket,
-                    expectContinueTrigger);
+                    expectContinueTrigger,
+                    h2Priority);
         }
 
     }

httpclient5/src/main/java/org/apache/hc/client5/http/impl/async/H2AsyncClientBuilder.java

@@ -701,7 +701,7 @@ public final H2AsyncClientBuilder evictIdleConnections(final TimeValue maxIdleTi
     }
 
     /**
-     * Enables emission of the RFC 9218 {@code Priority} request header for HTTP/2 requests.
+     * Enables emission of the {@code Priority} request header for HTTP/2 requests.
      * <p>
      * When enabled, {@link org.apache.hc.client5.http.protocol.H2RequestPriority} is added as the
      * last request interceptor. The header is omitted when the effective value equals the RFC

httpclient5/src/main/java/org/apache/hc/client5/http/protocol/H2RequestPriority.java

@@ -29,6 +29,7 @@
 
 import java.io.IOException;
 
+import org.apache.hc.client5.http.config.RequestConfig;
 import org.apache.hc.core5.annotation.Contract;
 import org.apache.hc.core5.annotation.Experimental;
 import org.apache.hc.core5.annotation.ThreadingBehavior;
@@ -47,14 +48,13 @@
 import org.apache.hc.core5.util.Args;
 
 /**
- * Emits  {@code Priority} request header for HTTP/2+.
+ * Adds the {@code Priority} request header to HTTP/2+ requests when a per-request
+ * priority is configured.
  * <p>
- * The priority value is taken from the request context attribute
- * {@link #ATTR_HTTP2_PRIORITY_VALUE}. If the formatted value equals
- * RFC defaults (u=3, i=false) the header is omitted.
- * <p>
- * If {@code overwrite} is {@code false} (default), an existing {@code Priority}
- * header set by the caller is preserved.
+ * The priority is taken from {@link RequestConfig#getH2Priority()}. If a {@code Priority}
+ * header is already present on the request, it is left unchanged. If formatting the
+ * configured value yields an empty string (e.g., because it encodes protocol defaults),
+ * the header is not added.
  *
  * @since 5.6
  */
@@ -63,59 +63,47 @@
 public final class H2RequestPriority implements HttpRequestInterceptor {
 
     /**
-     * Context attribute to carry a {@link PriorityValue}.
-     */
-    public static final String ATTR_HTTP2_PRIORITY_VALUE = "http2.priority.value";
-
-    /**
-     * Singleton with {@code overwrite=false}.
+     * Singleton instance.
      */
-    public static final H2RequestPriority INSTANCE = new H2RequestPriority(false);
-
-    private final boolean overwrite;
-
-    public H2RequestPriority() {
-        this(false);
-    }
-
-    public H2RequestPriority(final boolean overwrite) {
-        this.overwrite = overwrite;
-    }
+    public static final H2RequestPriority INSTANCE = new H2RequestPriority();
 
     @Override
-    public void process(final HttpRequest request, final EntityDetails entity,
-                        final HttpContext context) throws HttpException, IOException {
+    public void process(
+            final HttpRequest request,
+            final EntityDetails entity,
+            final HttpContext context) throws HttpException, IOException {
 
         Args.notNull(request, "HTTP request");
         Args.notNull(context, "HTTP context");
 
-        final ProtocolVersion ver = HttpCoreContext.cast(context).getProtocolVersion();
-        if (ver == null || ver.compareToVersion(HttpVersion.HTTP_2) < 0) {
+        final ProtocolVersion pv = HttpCoreContext.cast(context).getProtocolVersion();
+        if (pv == null || pv.compareToVersion(HttpVersion.HTTP_2) < 0) {
             return; // only for HTTP/2+
         }
 
+        // Do not override a header explicitly provided by the caller.
         final Header existing = request.getFirstHeader(HttpHeaders.PRIORITY);
-        if (existing != null && !overwrite) {
-            return; // respect caller-set header
+        if (existing != null) {
+            return;
         }
 
-        final PriorityValue pv = HttpCoreContext.cast(context)
-                .getAttribute(ATTR_HTTP2_PRIORITY_VALUE, PriorityValue.class);
-        if (pv == null) {
+        final RequestConfig requestConfig = org.apache.hc.client5.http.protocol.HttpClientContext
+                .cast(context)
+                .getRequestConfigOrDefault();
+        if (requestConfig == null) {
             return;
         }
 
-        final String value = PriorityFormatter.format(pv);
-        if (value == null || value.trim().isEmpty()) {
-            if (overwrite && request.getFirstHeader(HttpHeaders.PRIORITY) != null) {
-                request.removeHeaders(HttpHeaders.PRIORITY);
-            }
+        final PriorityValue pri = requestConfig.getH2Priority();
+        if (pri == null) {
             return;
         }
 
-        if (overwrite && request.getFirstHeader(HttpHeaders.PRIORITY) != null) {
-            request.removeHeaders(HttpHeaders.PRIORITY);
+        final String value = PriorityFormatter.format(pri);
+        if (value.isEmpty()) {
+            return;
         }
+
         request.addHeader(HttpHeaders.PRIORITY, value);
     }
-}
+}

httpclient5/src/test/java/org/apache/hc/client5/http/examples/ClientH2PriorityHeaderExample.java renamed to httpclient5/src/test/java/org/apache/hc/client5/http/examples/AsyncClientH2Priority.java

@@ -31,45 +31,84 @@
 import org.apache.hc.client5.http.async.methods.SimpleHttpRequest;
 import org.apache.hc.client5.http.async.methods.SimpleHttpResponse;
 import org.apache.hc.client5.http.async.methods.SimpleRequestBuilder;
+import org.apache.hc.client5.http.config.RequestConfig;
 import org.apache.hc.client5.http.impl.async.CloseableHttpAsyncClient;
 import org.apache.hc.client5.http.impl.async.H2AsyncClientBuilder;
-import org.apache.hc.client5.http.protocol.H2RequestPriority;
 import org.apache.hc.client5.http.protocol.HttpClientContext;
 import org.apache.hc.core5.annotation.Experimental;
 import org.apache.hc.core5.http2.config.H2Config;
 import org.apache.hc.core5.http2.priority.PriorityValue;
 
+/**
+ * Demonstrates sending the HTTP/2 {@code Priority} request header using per-request configuration.
+ *
+ * <p><strong>How it works</strong>:
+ * <ul>
+ *   <li>Call {@code enablePriorityHeader()} on the H2 client builder to register
+ *       {@link org.apache.hc.client5.http.protocol.H2RequestPriority}.</li>
+ *   <li>For each request, set a priority on the {@link RequestConfig} via
+ *       {@link RequestConfig.Builder#setH2Priority(PriorityValue)} and attach it to the
+ *       {@link HttpClientContext} passed to {@code execute}.</li>
+ * </ul>
+ *
+ * <p><strong>Notes</strong>:
+ * <ul>
+ *   <li>If a {@code Priority} header is already present on the request, it is preserved.</li>
+ *   <li>If the configured value encodes protocol defaults, the header is omitted.</li>
+ *   <li>Applies to HTTP/2+ only; HTTP/1.1 requests are unaffected.</li>
+ * </ul>
+ *
+ * @since 5.6
+ */
 @Experimental
-public class ClientH2PriorityHeaderExample {
+public class AsyncClientH2Priority {
 
     public static void main(final String[] args) throws Exception {
         try (CloseableHttpAsyncClient client = H2AsyncClientBuilder.create()
                 .setH2Config(H2Config.custom()
                         .setPushEnabled(false)
                         .build())
-                .enablePriorityHeader()   // wires H2RequestPriority into the chain
+                .enablePriorityHeader()   // registers H2RequestPriority in the chain
                 .build()) {
 
             client.start();
 
-            // --- Request 1: non-default priority -> header sent
+            // --- Request 1: non-default priority -> header sent (e.g., "u=0, i")
             final HttpClientContext ctx1 = HttpClientContext.create();
-            ctx1.setAttribute(H2RequestPriority.ATTR_HTTP2_PRIORITY_VALUE, PriorityValue.of(0, true));
+            ctx1.setRequestConfig(RequestConfig.custom()
+                    .setH2Priority(PriorityValue.of(0, true))
+                    .build());
 
             final SimpleHttpRequest req1 = SimpleRequestBuilder.get("https://nghttp2.org/httpbin/headers").build();
             final Future<SimpleHttpResponse> f1 = client.execute(req1, ctx1, null);
             final SimpleHttpResponse r1 = f1.get();
             System.out.println("[/httpbin/headers] -> " + r1.getCode());
+            System.out.println("Negotiated protocol (req1): " + ctx1.getProtocolVersion());
             System.out.println(r1.getBodyText());
 
             // --- Request 2: defaults -> header omitted
             final HttpClientContext ctx2 = HttpClientContext.create();
-            ctx2.setAttribute(H2RequestPriority.ATTR_HTTP2_PRIORITY_VALUE, PriorityValue.defaults());
+            ctx2.setRequestConfig(RequestConfig.custom()
+                    .setH2Priority(PriorityValue.defaults())
+                    .build());
 
             final SimpleHttpRequest req2 = SimpleRequestBuilder.get("https://nghttp2.org/httpbin/user-agent").build();
             final SimpleHttpResponse r2 = client.execute(req2, ctx2, null).get();
             System.out.println("[/httpbin/user-agent] -> " + r2.getCode());
+            System.out.println("Negotiated protocol (req2): " + ctx2.getProtocolVersion());
             System.out.println(r2.getBodyText());
+
+            // --- Request 3: user-provided header -> preserved (no overwrite)
+            final HttpClientContext ctx3 = HttpClientContext.create();
+            ctx3.setRequestConfig(RequestConfig.custom()
+                    .setH2Priority(PriorityValue.of(5, false))
+                    .build());
+            final SimpleHttpRequest req3 = SimpleRequestBuilder.get("https://nghttp2.org/httpbin/headers").build();
+            req3.addHeader("Priority", "u=2");
+            final SimpleHttpResponse r3 = client.execute(req3, ctx3, null).get();
+            System.out.println("[/httpbin/headers with user header] -> " + r3.getCode());
+            System.out.println("Negotiated protocol (req3): " + ctx3.getProtocolVersion());
+            System.out.println(r3.getBodyText());
         }
     }
 }