src/main/kotlin/de/uapcore/lightpit/filter/StaticFilesFilter.kt

package de.uapcore.lightpit.filter

import jakarta.servlet.FilterChain
import jakarta.servlet.annotation.WebFilter
import jakarta.servlet.http.HttpFilter
import jakarta.servlet.http.HttpServletRequest
import jakarta.servlet.http.HttpServletResponse

/*
 * Copyright 2023 Mike Becker. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

@WebFilter(urlPatterns = ["*.ttf", "*.css", "*.js"])
class StaticFilesFilter : HttpFilter() {
    override fun doFilter(req: HttpServletRequest, res: HttpServletResponse, chain: FilterChain) {
        // Apply a Cache-Control Header for static files to allow storing them
        // in shared cache for almost indefinitely. We will cache-bust them when we need an update.
        // RFC-2616 mandates that servers SHOULD NOT specify more than one year, though
        res.addHeader("Cache-Control", "public, max-age=31536000, immutable")
        super.doFilter(req, res, chain)
    }
}