assets: match If-None-Match lists and "*", and skip If-Modified-Since when If-None-Match is present

jooby/src/main/java/io/jooby/handler/AssetHandler.java

@@ -16,6 +16,7 @@
 import org.jspecify.annotations.Nullable;
 
 import io.jooby.*;
+import io.jooby.exception.TypeMismatchException;
 
 /**
  * Handler for static resources represented by the {@link Asset} contract.
@@ -98,9 +99,9 @@ public Object apply(Context ctx) throws Exception {
     CacheControl cacheParams = cacheControl.apply(resolvedPath);
 
     // handle If-None-Match
+    String ifnm = ctx.header("If-None-Match").valueOrNull();
     if (cacheParams.isEtag()) {
-      String ifnm = ctx.header("If-None-Match").valueOrNull();
-      if (ifnm != null && ifnm.equals(asset.getEtag())) {
+      if (ifnm != null && etagMatches(ifnm, asset.getEtag())) {
         ctx.send(StatusCode.NOT_MODIFIED);
         asset.close();
         return ctx;
@@ -109,11 +110,11 @@ public Object apply(Context ctx) throws Exception {
       }
     }
 
-    // Handle If-Modified-Since
+    // Handle If-Modified-Since, which is ignored when If-None-Match is present (RFC 9110, 13.2.2)
     if (cacheParams.isLastModified()) {
       long lastModified = asset.getLastModified();
       if (lastModified > 0) {
-        long ifms = ctx.header("If-Modified-Since").longValue(-1);
+        long ifms = ifnm == null ? ifModifiedSince(ctx) : -1;
         if (lastModified / ONE_SEC <= ifms / ONE_SEC) {
           ctx.send(StatusCode.NOT_MODIFIED);
           asset.close();
@@ -246,6 +247,37 @@ public AssetHandler notFound(SneakyThrows.Consumer<Context> handler) {
     return this;
   }
 
+  /**
+   * If-None-Match is "*" or a list of entity tags, compared with the weak comparison function (RFC
+   * 9110, section 13.1.2).
+   */
+  private static boolean etagMatches(String ifNoneMatch, String etag) {
+    if (ifNoneMatch.equals(etag)) {
+      return true;
+    }
+    String opaqueTag = opaqueTag(etag);
+    for (String tag : ifNoneMatch.split(",")) {
+      tag = tag.trim();
+      if (tag.equals("*") || opaqueTag(tag).equals(opaqueTag)) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  private static String opaqueTag(String etag) {
+    return etag.startsWith("W/") ? etag.substring(2) : etag;
+  }
+
+  /** An If-Modified-Since that is not a valid date is ignored (RFC 9110, section 13.1.3). */
+  private static long ifModifiedSince(Context ctx) {
+    try {
+      return ctx.header("If-Modified-Since").longValue(-1);
+    } catch (TypeMismatchException x) {
+      return -1;
+    }
+  }
+
   private @Nullable Asset resolve(String filepath) {
     for (AssetSource source : sources) {
       Asset asset = source.resolve(filepath);

jooby/src/test/java/io/jooby/handler/AssetHandlerTest.java

@@ -0,0 +1,93 @@
+/*
+ * Jooby https://jooby.io
+ * Apache License Version 2.0 https://jooby.io/LICENSE.txt
+ * Copyright 2014 Edgar Espina
+ */
+package io.jooby.handler;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.RETURNS_DEEP_STUBS;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import java.io.ByteArrayInputStream;
+import java.nio.charset.StandardCharsets;
+import java.time.Instant;
+import java.time.ZoneOffset;
+
+import org.jspecify.annotations.Nullable;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+import io.jooby.Context;
+import io.jooby.MediaType;
+import io.jooby.StatusCode;
+import io.jooby.value.Value;
+import io.jooby.value.ValueFactory;
+
+public class AssetHandlerTest {
+
+  private static final Instant LAST_MODIFIED = Instant.parse("2026-01-02T03:04:05Z");
+
+  private Asset asset;
+
+  private Context ctx;
+
+  @BeforeEach
+  void setUp() {
+    asset = mock(Asset.class);
+    when(asset.getEtag()).thenReturn("W/\"abc\"");
+    when(asset.getLastModified()).thenReturn(LAST_MODIFIED.toEpochMilli());
+    when(asset.getSize()).thenReturn(5L);
+    when(asset.getContentType()).thenReturn(MediaType.text);
+    when(asset.stream())
+        .thenReturn(new ByteArrayInputStream("hello".getBytes(StandardCharsets.UTF_8)));
+
+    ctx = mock(Context.class, RETURNS_DEEP_STUBS);
+    when(ctx.path((String) any()).value("index.html")).thenReturn("a.txt");
+  }
+
+  @ParameterizedTest(name = "If-None-Match: {0}, If-Modified-Since: {1} -> 304: {2}")
+  @CsvSource(
+      delimiter = '|',
+      nullValues = "none",
+      value = {
+        "W/\"abc\"                    | none          | true",
+        "\"abc\"                      | none          | true",
+        "\"x\", W/\"abc\"             | none          | true",
+        "\"x\",\"abc\"                | none          | true",
+        "*                            | none          | true",
+        "\"x\"                        | none          | false",
+        "\"x\"                        | last-modified | false",
+        "none                         | last-modified | true",
+        "none                         | yesterday     | false",
+      })
+  void conditionalRequest(
+      @Nullable String ifNoneMatch, @Nullable String ifModifiedSince, boolean notModified)
+      throws Exception {
+    header("If-None-Match", ifNoneMatch);
+    header(
+        "If-Modified-Since",
+        "last-modified".equals(ifModifiedSince)
+            ? Context.RFC1123.format(LAST_MODIFIED.atOffset(ZoneOffset.UTC))
+            : ifModifiedSince);
+
+    new AssetHandler(path -> asset).apply(ctx);
+
+    if (notModified) {
+      verify(ctx).send(StatusCode.NOT_MODIFIED);
+    } else {
+      verify(ctx, never()).send(StatusCode.NOT_MODIFIED);
+      verify(ctx).send(any(java.io.InputStream.class));
+    }
+  }
+
+  private void header(String name, @Nullable String value) {
+    ValueFactory factory = new ValueFactory();
+    Value header = value == null ? Value.missing(factory, name) : Value.value(factory, name, value);
+    when(ctx.header(name)).thenReturn(header);
+  }
+}