FileProvider.java

package net.scapeemulator.game.net.file;

import io.netty.channel.DefaultFileRegion;
import io.netty.channel.FileRegion;

import java.io.File;
import java.io.IOException;
import java.nio.channels.FileChannel;
import java.nio.file.StandardOpenOption;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public final class FileProvider {

    private final File root;
    private final boolean codeOnly;

    public FileProvider(String root, boolean codeOnly) {
        this.root = new File(root);
        this.codeOnly = codeOnly;
    }

    public FileRegion serve(String path) throws IOException {
        path = rewrite(path);
        if (codeOnly && !path.matches("^/(jogl_\\d_\\d\\.lib|(loader|loader_gl|runescape)\\.jar|(jogl|runescape|runescape_gl)\\.pack200|unpackclass.pack)$"))
            return null;

        File f = new File(root, path);
        if (!f.getAbsolutePath().startsWith(root.getAbsolutePath()))
            return null;

        if (!f.exists() || !f.isFile())
            return null;

        return new DefaultFileRegion(FileChannel.open(f.toPath(), StandardOpenOption.READ), 0, f.length());
    }

    private String rewrite(String path) {
        Pattern pattern = Pattern.compile("^/jogl_(\\d)_(\\d)_[0-9-]+\\.lib$");
        Matcher matcher = pattern.matcher(path);
        if (matcher.matches()) {
            return "/jogl_" + matcher.group(1) + "_" + matcher.group(2) + ".lib";
        }

        pattern = Pattern.compile("^/(jogl|runescape|runescape_gl)_[0-9-]+\\.pack200$");
        matcher = pattern.matcher(path);
        if (matcher.matches()) {
            return "/" + matcher.group(1) + ".pack200";
        }

        pattern = Pattern.compile("^/(loader|loader_gl|runescape)_[0-9-]+\\.jar$");
        matcher = pattern.matcher(path);
        if (matcher.matches()) {
            return "/" + matcher.group(1) + ".jar";
        }

        if (path.matches("^/unpackclass_[0-9-]+\\.pack$")) {
            return "/unpackclass.pack";
        }

        if (path.equals("/")) {
            return "/index.html";
        }

        return path;
    }

}