com.appslandia.plum.base.CorsPolicyHandler Maven / Gradle / Ivy

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// The MIT License (MIT)
// Copyright © 2015 AppsLandia. All rights reserved.

// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:

// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

package com.appslandia.plum.base;

import javax.enterprise.context.ApplicationScoped;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.appslandia.common.utils.AssertUtils;
import com.appslandia.plum.utils.ServletUtils;

/**
 *
 * @author Loc Ha
 *
 */
@ApplicationScoped
public class CorsPolicyHandler {

	public static final String HEADER_AC_ALLOW_ORIGIN = "Access-Control-Allow-Origin";
	public static final String HEADER_AC_ALLOW_METHODS = "Access-Control-Allow-Methods";
	public static final String HEADER_AC_ALLOW_HEADERS = "Access-Control-Allow-Headers";
	public static final String HEADER_AC_EXPOSE_HEADERS = "Access-Control-Expose-Headers";

	public static final String HEADER_AC_MAX_AGE = "Access-Control-Max-Age";
	public static final String HEADER_AC_ALLOW_CREDENTIALS = "Access-Control-Allow-Credentials";

	public static final String HEADER_ORIGIN = "Origin";
	public static final String HEADER_VARY = "Vary";

	public static final String HEADER_AC_REQUEST_METHOD = "Access-Control-Request-Method";
	public static final String HEADER_AC_REQUEST_HEADERS = "Access-Control-Request-Headers";

	public CorsResult handleCors(HttpServletRequest request, HttpServletResponse response, CorsPolicy corsPolicy) {
		// CORS Headers
		String origin = AssertUtils.assertNotNull(request.getHeader(HEADER_ORIGIN));

		// Origin
		if (!corsPolicy.allowOrigin(origin)) {
			return CorsResult.NOT_ALLOWED_ORIGIN;
		}

		// Allow-Origin
		response.setHeader(HEADER_AC_ALLOW_ORIGIN, corsPolicy.getAllowOrigin(origin));
		if (!corsPolicy.isAnyOrigin()) {
			response.addHeader(HEADER_VARY, HEADER_ORIGIN);
		}

		// Expose-Headers
		if (corsPolicy.getExposeHeadersString() != null) {
			response.setHeader(HEADER_AC_EXPOSE_HEADERS, corsPolicy.getExposeHeadersString());
		}
		return CorsResult.ALLOWED;
	}

	public CorsResult handlePreflight(HttpServletRequest request, HttpServletResponse response, CorsPolicy corsPolicy) {
		// CORS Headers
		String origin = AssertUtils.assertNotNull(request.getHeader(HEADER_ORIGIN));

		// Origin
		if (!corsPolicy.allowOrigin(origin)) {
			return CorsResult.NOT_ALLOWED_ORIGIN;
		}
		RequestContext requestContext = ServletUtils.getRequestContext(request);

		// Request Method
		String requestMethod = AssertUtils.assertNotNull(request.getHeader(HEADER_AC_REQUEST_METHOD));
		if (!requestContext.getActionDesc().getAllowMethods().contains(requestMethod)) {
			return CorsResult.NOT_ALLOWED_METHOD;
		}

		// Request Headers
		String requestHeaders = request.getHeader(HEADER_AC_REQUEST_HEADERS);
		if (requestHeaders != null) {
			if (!corsPolicy.allowHeaders(requestHeaders)) {
				return CorsResult.NOT_ALLOWED_HEADER;
			}
		}

		// Allow-Origin
		response.setHeader(HEADER_AC_ALLOW_ORIGIN, corsPolicy.getAllowOrigin(origin));
		if (!corsPolicy.isAnyOrigin()) {
			response.addHeader(HEADER_VARY, HEADER_ORIGIN);
		}

		// Allow-Methods
		response.setHeader(HEADER_AC_ALLOW_METHODS, requestContext.getActionDesc().getAllowMethodsString());

		// Allow-Headers
		if (corsPolicy.getAllowHeadersString() != null) {
			response.setHeader(HEADER_AC_ALLOW_HEADERS, corsPolicy.getAllowHeadersString());
		}

		// Allow-Credentials
		if (corsPolicy.isAllowCredentials()) {
			response.setHeader(HEADER_AC_ALLOW_CREDENTIALS, Boolean.toString(corsPolicy.isAllowCredentials()));
		}

		// Max-Age
		response.setHeader(HEADER_AC_MAX_AGE, Integer.toString(corsPolicy.getMaxAge()));
		return CorsResult.ALLOWED;
	}

	public static enum CorsResult {
		ALLOWED, NOT_ALLOWED_ORIGIN, NOT_ALLOWED_METHOD, NOT_ALLOWED_HEADER, NOT_ALLOWED_CORS
	}
}