Updating isCachedClientSide method to ignore If-Modified-Since when If-None-Match is also specified

src/main/java/io/dropwizard/bundles/assets/AssetServlet.java

@@ -231,9 +231,26 @@ protected void doGet(HttpServletRequest req, HttpServletResponse resp)
  }
 
  private boolean isCachedClientSide(HttpServletRequest req, Asset cachedAsset) {
- return cachedAsset.getETag().equals(req.getHeader(HttpHeaders.IF_NONE_MATCH))
- || (req.getDateHeader(HttpHeaders.IF_MODIFIED_SINCE)
- >= cachedAsset.getLastModifiedTime());
+ String ifNoneMatchHeader = req.getHeader(HttpHeaders.IF_NONE_MATCH);
+ long ifModifiedSinceHeader = req.getDateHeader(HttpHeaders.IF_MODIFIED_SINCE);
+
+ boolean ifNoneMatchHeaderExists = ifNoneMatchHeader != null && !ifNoneMatchHeader.isEmpty();
+ boolean ifModifiedSinceHeaderExists = ifModifiedSinceHeader >= 0;
+
+ // If there is an If-None-Match header, determine caching based on eTag.
+ // Per RFC 7232, if If-None-Match is present, ignore If-Modified-Since.
+ if (ifNoneMatchHeaderExists) {
+ return cachedAsset.getETag().equals(ifNoneMatchHeader);
+ } else if (ifModifiedSinceHeaderExists) {
+ // If there is no If-None-Match header, but there is an If-Modified-Since header,
+ // determine caching based on last modified time.
+ return ifModifiedSinceHeader >= cachedAsset.getLastModifiedTime();
+ } else {
+ // If there is neither an If-None-Match header nor am If-Modified-Since header,
+ // we cannot determine that the entity is cached.
+ return false;
+ }
+
  }
 
  /**

src/test/java/io/dropwizard/bundles/assets/AssetServletTest.java

@@ -410,6 +410,58 @@ public void supportsIfModifiedSinceRequests() throws Exception {
  .isEqualTo(304);
  }
 
+ @Test
+ // Verify conformance with the HTTP/1.1 spec which requires ignoring the If-Modified-Since
+ // header when the If-None-Match header is present (RFC 7232).
+ public void supportsIfNoneMatchAndIfModifiedSinceRequests() throws Exception {
+ response = makeRequest();
+ final long lastModifiedTime = response.getDateField(HttpHeaders.LAST_MODIFIED);
+ final String correctEtag = response.get(HttpHeaders.ETAG);
+
+ request.putDateField(HttpHeaders.IF_MODIFIED_SINCE, lastModifiedTime);
+ request.setHeader(HttpHeaders.IF_NONE_MATCH, correctEtag);
+ response = makeRequest();
+ final int statusWithMatchingLastModifiedTimeAndMatchingEtag = response.getStatus();
+
+ request.putDateField(HttpHeaders.IF_MODIFIED_SINCE, lastModifiedTime - 100);
+ request.setHeader(HttpHeaders.IF_NONE_MATCH, correctEtag);
+ response = makeRequest();
+ final int statusWithStaleLastModifiedTimeAndMatchingEtag = response.getStatus();
+
+ request.putDateField(HttpHeaders.IF_MODIFIED_SINCE, lastModifiedTime + 100);
+ request.setHeader(HttpHeaders.IF_NONE_MATCH, correctEtag);
+ response = makeRequest();
+ final int statusWithRecentLastModifiedTimeAndMatchingEtag = response.getStatus();
+
+ request.putDateField(HttpHeaders.IF_MODIFIED_SINCE, lastModifiedTime);
+ request.setHeader(HttpHeaders.IF_NONE_MATCH, correctEtag + "FOO");
+ response = makeRequest();
+ final int statusWithMatchingLastModifiedTimeAndNonMatchingEtag = response.getStatus();
+
+ request.putDateField(HttpHeaders.IF_MODIFIED_SINCE, lastModifiedTime - 100);
+ request.setHeader(HttpHeaders.IF_NONE_MATCH, correctEtag + "FOO");
+ response = makeRequest();
+ final int statusWithStaleLastModifiedTimeAndNonMatchingEtag = response.getStatus();
+
+ request.putDateField(HttpHeaders.IF_MODIFIED_SINCE, lastModifiedTime + 100);
+ request.setHeader(HttpHeaders.IF_NONE_MATCH, correctEtag + "FOO");
+ response = makeRequest();
+ final int statusWithRecentLastModifiedTimeAndNonMatchingEtag = response.getStatus();
+
+ assertThat(statusWithMatchingLastModifiedTimeAndMatchingEtag)
+ .isEqualTo(304);
+ assertThat(statusWithStaleLastModifiedTimeAndMatchingEtag)
+ .isEqualTo(304);
+ assertThat(statusWithRecentLastModifiedTimeAndMatchingEtag)
+ .isEqualTo(304);
+ assertThat(statusWithMatchingLastModifiedTimeAndNonMatchingEtag)
+ .isEqualTo(200);
+ assertThat(statusWithStaleLastModifiedTimeAndNonMatchingEtag)
+ .isEqualTo(200);
+ assertThat(statusWithRecentLastModifiedTimeAndNonMatchingEtag)
+ .isEqualTo(200);
+ }
+
  @Test
  public void guessesMimeTypes() throws Exception {
  response = makeRequest();