ServletPathSpec.java

//
//  ========================================================================
//  Copyright (c) 1995-2020 Mort Bay Consulting Pty Ltd and others.
//  ------------------------------------------------------------------------
//  All rights reserved. This program and the accompanying materials
//  are made available under the terms of the Eclipse Public License v1.0
//  and Apache License v2.0 which accompanies this distribution.
//
//      The Eclipse Public License is available at
//      http://www.eclipse.org/legal/epl-v10.html
//
//      The Apache License v2.0 is available at
//      http://www.opensource.org/licenses/apache2.0.php
//
//  You may elect to redistribute this code under either of these licenses.
//  ========================================================================
//

package org.eclipse.jetty.http.pathmap;

import org.eclipse.jetty.util.StringUtil;
import org.eclipse.jetty.util.log.Log;
import org.eclipse.jetty.util.log.Logger;

public class ServletPathSpec extends AbstractPathSpec
{
    private static final Logger LOG = Log.getLogger(ServletPathSpec.class);

    private final PathSpecGroup _group;
    private final int _pathDepth;
    private final int _specLength;
    private final String _prefix;
    private final String _suffix;

    /**
     * Normalize servlet path spec:<ul>
     *     <li>"path/*" to "/path/*"</li>
     * </ul>
     * @param pathSpec the servlet or filter mapping pattern
     * @return the pathSpec prefixed by '/' if appropriate
     */
    public static String normalize(String pathSpec)
    {
        if (StringUtil.isNotBlank(pathSpec) && !pathSpec.startsWith("/") && !pathSpec.startsWith("*"))
            return "/" + pathSpec;
        return pathSpec;
    }

    /**
     * Sanitize servlet path spec:<ul>
     *     <li>null pathspec to ""</li>
     *     <li>"servlet|spec" to "spec"</li>
     * </ul>
     * @param pathSpec the servlet or filter mapping pattern
     * @return the pathSpec prefixed by '/' if appropriate
     */
    private static String sanitize(String pathSpec)
    {
        // TODO can this be combined with normalize?
        if (StringUtil.isEmpty(pathSpec))
            return "";
        if (pathSpec.startsWith("servlet|"))
            pathSpec = pathSpec.substring("servlet|".length());
        return pathSpec;
    }

    public ServletPathSpec(String servletPathSpec)
    {
        super(sanitize(servletPathSpec));
        String declaration = getDeclaration();
        assertValidServletPathSpec(declaration);

        // The Root Path Spec
        if ("".equals(declaration))
        {
            _group = PathSpecGroup.ROOT;
            _pathDepth = -1; // Set pathDepth to -1 to force this to be at the end of the sort order.
            _specLength = 1;
            _prefix = null;
            _suffix = null;
            return;
        }

        // The Default Path Spec
        if ("/".equals(declaration))
        {
            _group = PathSpecGroup.DEFAULT;
            _pathDepth = -1; // Set pathDepth to -1 to force this to be at the end of the sort order.
            _specLength = 1;
            _prefix = null;
            _suffix = null;
            return;
        }

        int specLength = declaration.length();
        PathSpecGroup group;
        String prefix;
        String suffix;

        // prefix based
        if (declaration.charAt(0) == '/' && declaration.endsWith("/*"))
        {
            group = PathSpecGroup.PREFIX_GLOB;
            prefix = declaration.substring(0, specLength - 2);
            suffix = null;
        }
        // suffix based
        else if (declaration.charAt(0) == '*' && declaration.length() > 1)
        {
            group = PathSpecGroup.SUFFIX_GLOB;
            prefix = null;
            suffix = declaration.substring(2, specLength);
        }
        else
        {
            group = PathSpecGroup.EXACT;
            prefix = declaration;
            suffix = null;
            if (declaration.endsWith("*"))
            {
                LOG.warn("Suspicious URL pattern: '{}'; see sections 12.1 and 12.2 of the Servlet specification",
                    declaration);
            }
        }

        int pathDepth = 0;
        for (int i = 0; i < specLength; i++)
        {
            int cp = declaration.codePointAt(i);
            if (cp < 128)
            {
                char c = (char)cp;
                if (c == '/')
                    pathDepth++;
            }
        }

        _group = group;
        _pathDepth = pathDepth;
        _specLength = specLength;
        _prefix = prefix;
        _suffix = suffix;
    }

    @Override
    public boolean is(String pathSpec)
    {
        return getDeclaration().equals(normalize(pathSpec));
    }

    private static void assertValidServletPathSpec(String servletPathSpec)
    {
        if ((servletPathSpec == null) || servletPathSpec.equals(""))
        {
            return; // empty path spec
        }

        int len = servletPathSpec.length();
        // path spec must either start with '/' or '*.'
        if (servletPathSpec.charAt(0) == '/')
        {
            // Prefix Based
            if (len == 1)
            {
                return; // simple '/' path spec
            }
            int idx = servletPathSpec.indexOf('*');
            if (idx < 0)
            {
                return; // no hit on glob '*'
            }
            // only allowed to have '*' at the end of the path spec
            if (idx != (len - 1))
            {
                throw new IllegalArgumentException("Servlet Spec 12.2 violation: glob '*' can only exist at end of prefix based matches: bad spec \"" + servletPathSpec + "\"");
            }
        }
        else if (servletPathSpec.startsWith("*."))
        {
            // Suffix Based
            int idx = servletPathSpec.indexOf('/');
            // cannot have path separator
            if (idx >= 0)
                throw new IllegalArgumentException("Servlet Spec 12.2 violation: suffix based path spec cannot have path separators: bad spec \"" + servletPathSpec + "\"");

            idx = servletPathSpec.indexOf('*', 2);
            // only allowed to have 1 glob '*', at the start of the path spec
            if (idx >= 1)
                throw new IllegalArgumentException("Servlet Spec 12.2 violation: suffix based path spec cannot have multiple glob '*': bad spec \"" + servletPathSpec + "\"");
        }
        else
        {
            throw new IllegalArgumentException("Servlet Spec 12.2 violation: path spec must start with \"/\" or \"*.\": bad spec \"" + servletPathSpec + "\"");
        }
    }

    @Override
    public int getSpecLength()
    {
        return _specLength;
    }

    @Override
    public PathSpecGroup getGroup()
    {
        return _group;
    }

    @Override
    public int getPathDepth()
    {
        return _pathDepth;
    }

    @Override
    public String getPathInfo(String path)
    {
        switch (_group)
        {
            case ROOT:
                return path;

            case PREFIX_GLOB:
                if (path.length() == (_specLength - 2))
                    return null;
                return path.substring(_specLength - 2);

            default:
                return null;
        }
    }

    @Override
    public String getPathMatch(String path)
    {
        switch (_group)
        {
            case ROOT:
                return "";

            case EXACT:
                if (getDeclaration().equals(path))
                    return path;
                return null;

            case PREFIX_GLOB:
                if (isWildcardMatch(path))
                    return path.substring(0, _specLength - 2);
                return null;

            case SUFFIX_GLOB:
                if (path.regionMatches(path.length() - (_specLength - 1), getDeclaration(), 1, _specLength - 1))
                    return path;
                return null;

            case DEFAULT:
                return path;

            default:
                return null;
        }
    }

    @Override
    public String getPrefix()
    {
        return _prefix;
    }

    @Override
    public String getSuffix()
    {
        return _suffix;
    }

    private boolean isWildcardMatch(String path)
    {
        // For a spec of "/foo/*" match "/foo" , "/foo/..." but not "/foobar"
        int cpl = _specLength - 2;
        if ((_group == PathSpecGroup.PREFIX_GLOB) && (path.regionMatches(0, getDeclaration(), 0, cpl)))
            return (path.length() == cpl) || ('/' == path.charAt(cpl));
        return false;
    }

    @Override
    public boolean matches(String path)
    {
        switch (_group)
        {
            case EXACT:
                return getDeclaration().equals(path);
            case PREFIX_GLOB:
                return isWildcardMatch(path);
            case SUFFIX_GLOB:
                return path.regionMatches((path.length() - _specLength) + 1, getDeclaration(), 1, _specLength - 1);
            case ROOT:
                // Only "/" matches
                return ("/".equals(path));
            case DEFAULT:
                // If we reached this point, then everything matches
                return true;
            default:
                return false;
        }
    }
}