org.raml.parser.loader.FileResourceLoader Maven / Gradle / Ivy

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Java implementation of the raml parser taken from https://github.com/raml-org/raml-java-parser and adjusted
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/*
 * Copyright 2013 (c) MuleSoft, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the License.
 */
package org.raml.parser.loader;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;
import java.nio.file.Path;
import java.nio.file.Paths;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


public class FileResourceLoader implements ResourceLoader
{

	private static final Logger LOG = LoggerFactory.getLogger(FileResourceLoader.class);

	private final File parentPath;

	protected final Logger logger = LoggerFactory.getLogger(getClass());

	public FileResourceLoader(final String path)
	{
		this(new File(path));
	}

	public FileResourceLoader(final File path)
	{
		this.parentPath = path;
	}

	@Override
	public InputStream fetchResource(final String resourceName)
	{
		final File includedFile = new File(parentPath, resourceName);
    	if (!includedFile.exists())
    	{
    		return null;
    	}
		
		sanitizePath(Paths.get(parentPath.getAbsolutePath()), Paths.get(resourceName));

		final FileInputStream inputStream = null;
		if (logger.isDebugEnabled())
		{
			logger.debug(String.format("Looking for resource: %s on directory: %s...", resourceName, parentPath));
		}
		try
		{
			return new FileInputStream(includedFile);
		}
		catch (final FileNotFoundException e)
		{
			// ignore
		}
		return inputStream;
	}

	/**
	 * Method to sanitize given path accordingly to allowed root application folder.
	 *
	 * @param rootPath a top level accessible folder path
	 * @param requestedPath the requested relative path
	 * @throws IllegalArgumentException throw in case the given requestedPath is
	 *            
	 *            absolute path
	 *            can not be represented in canonical way
	 *            is traverses up the the folder structure out of the rootPath bounds
	 *            
	 */
	private void sanitizePath(final Path rootPath, final Path requestedPath)//
	{
		if (requestedPath.isAbsolute())
		{
			LOG.error("Not allowed to access directly absolute path " + requestedPath);
			throw new IllegalArgumentException("Not allowed to access directly absolute paths.");
		}

		final Path normalizedRequestedPath = rootPath.resolve(requestedPath).normalize();
		final Path normalizedServletRootPath = rootPath.normalize();

		if (!normalizedRequestedPath.startsWith(normalizedServletRootPath))
		{
			LOG.error("Requested resource " + requestedPath + " is not relatively located inside the allowed web application "
					+ "root folder " + rootPath);
			throw new IllegalArgumentException("Requested resource is not relatively located inside the allowed web application "
					+ "root folder.");
		}

	}
}