org.cryptomator.frontend.webdav.DefaultServlet.java Source code

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Here is the source code for org.cryptomator.frontend.webdav.DefaultServlet.java

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/*******************************************************************************
 * Copyright (c) 2016 Sebastian Stenzel and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the accompanying LICENSE.txt.
 *
 * Contributors:
 *     Sebastian Stenzel - initial API and implementation
 *******************************************************************************/
package org.cryptomator.frontend.webdav;

import java.io.IOException;
import java.util.Collection;
import java.util.Objects;

import javax.inject.Inject;
import javax.inject.Singleton;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.lang3.StringUtils;
import org.cryptomator.frontend.webdav.WebDavServerModule.ContextPaths;

@Singleton
class DefaultServlet extends HttpServlet {

    private static final int TARPIT_DELAY_MS = 5000;
    private final Collection<String> contextPaths;

    @Inject
    public DefaultServlet(@ContextPaths Collection<String> contextPaths) {
        this.contextPaths = contextPaths;
    }

    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        if (!isRequestedResourcePathPartOfValidContextPath(req.getRequestURI())) {
            try {
                resp.addHeader("X-Tarpit-Delayed", TARPIT_DELAY_MS + "ms");
                Thread.sleep(TARPIT_DELAY_MS);
            } catch (InterruptedException e) {
                resp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, "Thread interrupted.");
                Thread.currentThread().interrupt();
                return;
            }
        }
        super.service(req, resp);
    }

    @Override
    protected void doOptions(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        resp.addHeader("DAV", "1, 2");
        resp.addHeader("MS-Author-Via", "DAV");
        resp.addHeader("Allow", "OPTIONS, GET, HEAD");
        resp.setStatus(HttpServletResponse.SC_NO_CONTENT);
    }

    private boolean isRequestedResourcePathPartOfValidContextPath(String requestedResourcePath) {
        return contextPaths.stream().filter(cp -> isParentOrSamePath(cp, requestedResourcePath)).findAny()
                .isPresent();
    }

    private boolean isParentOrSamePath(String path, String potentialParent) {
        String[] pathComponents = StringUtils.split(Objects.requireNonNull(path), '/');
        String[] parentPathComponents = StringUtils.split(Objects.requireNonNull(potentialParent), '/');
        if (pathComponents.length < parentPathComponents.length) {
            return false; // parent can not be parent of path, if it is longer than path.
        }
        assert pathComponents.length >= parentPathComponents.length;
        for (int i = 0; i < parentPathComponents.length; i++) {
            if (!pathComponents[i].equals(parentPathComponents[i])) {
                return false;
            }
        }
        return true;
    }

}