001/*
002 * Copyright 2002-2013 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.web.servlet.support;
018
019import java.util.Map;
020import javax.servlet.http.HttpServletRequest;
021
022/**
023 * A contract for inspecting and potentially modifying request data values such
024 * as URL query parameters or form field values before they are rendered by a
025 * view or before a redirect.
026 *
027 * <p>Implementations may use this contract for example as part of a solution
028 * to provide data integrity, confidentiality, protection against cross-site
029 * request forgery (CSRF), and others or for other tasks such as automatically
030 * adding a hidden field to all forms and URLs.
031 *
032 * <p>View technologies that support this contract can obtain an instance to
033 * delegate to via {@link RequestContext#getRequestDataValueProcessor()}.
034 *
035 * @author Rossen Stoyanchev
036 * @since 3.1
037 */
038public interface RequestDataValueProcessor {
039
040        /**
041         * Invoked when a new form action is rendered.
042         * @param request the current request
043         * @param action the form action
044         * @param httpMethod the form HTTP method
045         * @return the action to use, possibly modified
046         */
047        String processAction(HttpServletRequest request, String action, String httpMethod);
048
049        /**
050         * Invoked when a form field value is rendered.
051         * @param request the current request
052         * @param name the form field name
053         * @param value the form field value
054         * @param type the form field type ("text", "hidden", etc.)
055         * @return the form field value to use, possibly modified
056         */
057        String processFormFieldValue(HttpServletRequest request, String name, String value, String type);
058
059        /**
060         * Invoked after all form fields have been rendered.
061         * @param request the current request
062         * @return additional hidden form fields to be added, or {@code null}
063         */
064        Map<String, String> getExtraHiddenFields(HttpServletRequest request);
065
066        /**
067         * Invoked when a URL is about to be rendered or redirected to.
068         * @param request the current request
069         * @param url the URL value
070         * @return the URL to use, possibly modified
071         */
072        String processUrl(HttpServletRequest request, String url);
073
074}