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package tools.refinery.language.web;
import jakarta.servlet.*;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import org.eclipse.jetty.http.HttpHeader;
import java.io.IOException;
import java.time.Duration;
import java.util.Set;
import java.util.regex.Pattern;
public class CacheControlFilter implements Filter {
private static final Pattern CACHE_URI_PATTERN = Pattern.compile(".*\\.(css|gif|js|map|png|svg|woff2?)");
private static final Set<String> CACHE_URI_DENYLIST = Set.of("apple-touch-icon.png", "favicon.png", "favicon.svg",
"favicon-96x96.png", "icon-any.svg", "icon-192x192.png", "icon-512x512.png", "mask-icon.svg", "sw.js");
private static final Duration EXPIRY = Duration.ofDays(365);
private static final String CACHE_CONTROL_CACHE_VALUE = "public, max-age: " + EXPIRY.toSeconds() + ", immutable";
private static final String CACHE_CONTROL_NO_CACHE_VALUE = "no-cache, no-store, max-age: 0, must-revalidate";
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
if (request instanceof HttpServletRequest httpRequest && response instanceof HttpServletResponse httpResponse) {
var requestURI = httpRequest.getRequestURI();
if (CACHE_URI_PATTERN.matcher(requestURI).matches() && !CACHE_URI_DENYLIST.contains(requestURI)) {
httpResponse.setHeader(HttpHeader.CACHE_CONTROL.asString(), CACHE_CONTROL_CACHE_VALUE);
httpResponse.setDateHeader(HttpHeader.EXPIRES.asString(),
System.currentTimeMillis() + EXPIRY.toMillis());
} else {
httpResponse.setHeader(HttpHeader.CACHE_CONTROL.asString(), CACHE_CONTROL_NO_CACHE_VALUE);
httpResponse.setDateHeader(HttpHeader.EXPIRES.asString(), 0);
}
}
chain.doFilter(request, response);
}
}
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