Support of Cache-Control header is only partial

[NiccoMlt]

While looking at the block code below to figure out if WebP images would be cached correctly:

carapaceproxy/carapace-server/src/main/java/org/carapaceproxy/server/cache/ContentsCache.java

Lines 188 to 200 in fe1cfdf

	switch (extension) {
	case "png":
	case "gif":
	case "jpg":
	case "jpeg":
	case "js":
	case "css":
	case "woff2":
	return true;
	default:
	return false;
	}
	}

we figured out that caching strategy implemented by isChached methods is a little naïve. Taking a look the the actual code:

carapaceproxy/carapace-server/src/main/java/org/carapaceproxy/server/cache/ContentsCache.java

Lines 122 to 131 in fe1cfdf

	public boolean isCacheable(HttpClientResponse response) {
	HttpHeaders headers = response.responseHeaders();
	String cacheControl = headers.get(HttpHeaderNames.CACHE_CONTROL, "").replaceAll(" ", "").toLowerCase();
	if ((!cacheControl.isEmpty() && CACHE_CONTROL_CACHE_DISABLED_VALUES.stream().anyMatch(v -> cacheControl.contains(v)))
	|| headers.contains(HttpHeaderNames.PRAGMA, HttpHeaderValues.NO_CACHE, true)
	|| !isContentLengthCacheable(headers)) {
	// never cache Pragma: no-cache, Cache-Control: nostore/no-cache
	LOG.log(Level.FINER, "not cacheable {0}", response);
	return false;
	}

carapaceproxy/carapace-server/src/main/java/org/carapaceproxy/server/cache/ContentsCache.java

Lines 155 to 172 in fe1cfdf

	final HttpHeaders headers = request.getRequestHeaders();
	final String cacheControl = headers.get(HttpHeaderNames.CACHE_CONTROL, "").replaceAll(" ", "").toLowerCase();
	boolean ctrlF5 = cacheControl.contains(HttpHeaderValues.NO_CACHE + "");
	if (ctrlF5) {
	if (registerNoCacheStat) {
	NO_CACHE_REQUESTS_COUNTER.inc();
	}
	return false;
	}
	if (this.currentConfiguration.isCacheDisabledForSecureRequestsWithoutPublic()
	&& request.isSecure() && !cacheControl.contains(HttpHeaderValues.PUBLIC + "")) {
	return false;
	}
	if ((!cacheControl.isEmpty() && CACHE_CONTROL_CACHE_DISABLED_VALUES.stream().anyMatch(v -> cacheControl.contains(v)))
	|| headers.contains(HttpHeaderNames.PRAGMA, HttpHeaderValues.NO_CACHE, true)) {
	// never cache Pragma: no-cache, Cache-Control: nostore/no-cache
	return false;
	}

it is especially evident that we don't actually support all the Cache-Control values.

Request	Response
max-age	max-age
max-stale	-
min-fresh	-
-	s-maxage
no-cache	no-cache
no-store	no-store
no-transform	no-transform
only-if-cached	-
-	must-revalidate
-	proxy-revalidate
-	must-understand
-	private
-	public
-	immutable
-	stale-while-revalidate
stale-if-error	stale-if-error