/*
 * Copyright 2002-2018 the original author or authors.
 *
 * 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.springframework.web.filter;

import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Enumeration;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import javax.servlet.http.HttpServletResponse;

import org.springframework.http.HttpInputMessage;
import org.springframework.http.MediaType;
import org.springframework.http.converter.FormHttpMessageConverter;
import org.springframework.http.converter.support.AllEncompassingFormHttpMessageConverter;
import org.springframework.http.server.ServletServerHttpRequest;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.MultiValueMap;
import org.springframework.util.StringUtils;

Filter that makes form encoded data available through the ServletRequest.getParameter*() family of methods during HTTP PUT or PATCH requests. 
The Servlet spec requires form data to be available for HTTP POST but not for HTTP PUT or PATCH requests. This filter intercepts HTTP PUT and PATCH requests where content type is 'application/x-www-form-urlencoded', reads form encoded content from the body of the request, and wraps the ServletRequest in order to make the form data available as request parameters just like it is for HTTP POST requests. 
Author:
Rossen Stoyanchev
Since:
3.1
Deprecated:
as of 5.1 in favor of FormContentFilter which is the same but also handles DELETE./**
 * {@link javax.servlet.Filter} that makes form encoded data available through
 * the {@code ServletRequest.getParameter*()} family of methods during HTTP PUT
 * or PATCH requests.
 *
 * <p>The Servlet spec requires form data to be available for HTTP POST but
 * not for HTTP PUT or PATCH requests. This filter intercepts HTTP PUT and PATCH
 * requests where content type is {@code 'application/x-www-form-urlencoded'},
 * reads form encoded content from the body of the request, and wraps the ServletRequest
 * in order to make the form data available as request parameters just like
 * it is for HTTP POST requests.
 *
 * @author Rossen Stoyanchev
 * @since 3.1
 * @deprecated as of 5.1 in favor of {@link FormContentFilter} which is the same
 * but also handles DELETE.
 */
@Deprecated
public class HttpPutFormContentFilter extends OncePerRequestFilter {

	private FormHttpMessageConverter formConverter = new AllEncompassingFormHttpMessageConverter();


	
Set the converter to use for parsing form content.
By default this is an instance of AllEncompassingFormHttpMessageConverter. /**
	 * Set the converter to use for parsing form content.
	 * <p>By default this is an instance of {@link AllEncompassingFormHttpMessageConverter}.
	 */
	public void setFormConverter(FormHttpMessageConverter converter) {
		Assert.notNull(converter, "FormHttpMessageConverter is required.");
		this.formConverter = converter;
	}

	public FormHttpMessageConverter getFormConverter() {
		return this.formConverter;
	}

	
The default character set to use for reading form data.
This is a shortcut for:
 getFormConverter.setCharset(charset). /**
	 * The default character set to use for reading form data.
	 * This is a shortcut for:<br>
	 * {@code getFormConverter.setCharset(charset)}.
	 */
	public void setCharset(Charset charset) {
		this.formConverter.setCharset(charset);
	}


	@Override
	protected void doFilterInternal(final HttpServletRequest request, HttpServletResponse response,
			FilterChain filterChain) throws ServletException, IOException {

		if (("PUT".equals(request.getMethod()) || "PATCH".equals(request.getMethod())) && isFormContentType(request)) {
			HttpInputMessage inputMessage = new ServletServerHttpRequest(request) {
				@Override
				public InputStream getBody() throws IOException {
					return request.getInputStream();
				}
			};
			MultiValueMap<String, String> formParameters = this.formConverter.read(null, inputMessage);
			if (!formParameters.isEmpty()) {
				HttpServletRequest wrapper = new HttpPutFormContentRequestWrapper(request, formParameters);
				filterChain.doFilter(wrapper, response);
				return;
			}
		}

		filterChain.doFilter(request, response);
	}

	private boolean isFormContentType(HttpServletRequest request) {
		String contentType = request.getContentType();
		if (contentType != null) {
			try {
				MediaType mediaType = MediaType.parseMediaType(contentType);
				return (MediaType.APPLICATION_FORM_URLENCODED.includes(mediaType));
			}
			catch (IllegalArgumentException ex) {
				return false;
			}
		}
		else {
			return false;
		}
	}


	private static class HttpPutFormContentRequestWrapper extends HttpServletRequestWrapper {

		private MultiValueMap<String, String> formParameters;

		public HttpPutFormContentRequestWrapper(HttpServletRequest request, MultiValueMap<String, String> parameters) {
			super(request);
			this.formParameters = parameters;
		}

		@Override
		@Nullable
		public String getParameter(String name) {
			String queryStringValue = super.getParameter(name);
			String formValue = this.formParameters.getFirst(name);
			return (queryStringValue != null ? queryStringValue : formValue);
		}

		@Override
		public Map<String, String[]> getParameterMap() {
			Map<String, String[]> result = new LinkedHashMap<>();
			Enumeration<String> names = getParameterNames();
			while (names.hasMoreElements()) {
				String name = names.nextElement();
				result.put(name, getParameterValues(name));
			}
			return result;
		}

		@Override
		public Enumeration<String> getParameterNames() {
			Set<String> names = new LinkedHashSet<>();
			names.addAll(Collections.list(super.getParameterNames()));
			names.addAll(this.formParameters.keySet());
			return Collections.enumeration(names);
		}

		@Override
		@Nullable
		public String[] getParameterValues(String name) {
			String[] parameterValues = super.getParameterValues(name);
			List<String> formParam = this.formParameters.get(name);
			if (formParam == null) {
				return parameterValues;
			}
			if (parameterValues == null || getQueryString() == null) {
				return StringUtils.toStringArray(formParam);
			}
			else {
				List<String> result = new ArrayList<>(parameterValues.length + formParam.size());
				result.addAll(Arrays.asList(parameterValues));
				result.addAll(formParam);
				return StringUtils.toStringArray(result);
			}
		}
	}

}