001/* 002 * Copyright 2002-2018 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.http.server; 018 019import java.io.IOException; 020import java.io.OutputStream; 021import java.util.ArrayList; 022import java.util.Collection; 023import java.util.List; 024 025import javax.servlet.http.HttpServletResponse; 026 027import org.springframework.http.HttpHeaders; 028import org.springframework.http.HttpStatus; 029import org.springframework.lang.Nullable; 030import org.springframework.util.Assert; 031import org.springframework.util.CollectionUtils; 032 033/** 034 * {@link ServerHttpResponse} implementation that is based on a {@link HttpServletResponse}. 035 * 036 * @author Arjen Poutsma 037 * @author Rossen Stoyanchev 038 * @since 3.0 039 */ 040public class ServletServerHttpResponse implements ServerHttpResponse { 041 042 private final HttpServletResponse servletResponse; 043 044 private final HttpHeaders headers; 045 046 private boolean headersWritten = false; 047 048 private boolean bodyUsed = false; 049 050 051 /** 052 * Construct a new instance of the ServletServerHttpResponse based on the given {@link HttpServletResponse}. 053 * @param servletResponse the servlet response 054 */ 055 public ServletServerHttpResponse(HttpServletResponse servletResponse) { 056 Assert.notNull(servletResponse, "HttpServletResponse must not be null"); 057 this.servletResponse = servletResponse; 058 this.headers = new ServletResponseHttpHeaders(); 059 } 060 061 062 /** 063 * Return the {@code HttpServletResponse} this object is based on. 064 */ 065 public HttpServletResponse getServletResponse() { 066 return this.servletResponse; 067 } 068 069 @Override 070 public void setStatusCode(HttpStatus status) { 071 Assert.notNull(status, "HttpStatus must not be null"); 072 this.servletResponse.setStatus(status.value()); 073 } 074 075 @Override 076 public HttpHeaders getHeaders() { 077 return (this.headersWritten ? HttpHeaders.readOnlyHttpHeaders(this.headers) : this.headers); 078 } 079 080 @Override 081 public OutputStream getBody() throws IOException { 082 this.bodyUsed = true; 083 writeHeaders(); 084 return this.servletResponse.getOutputStream(); 085 } 086 087 @Override 088 public void flush() throws IOException { 089 writeHeaders(); 090 if (this.bodyUsed) { 091 this.servletResponse.flushBuffer(); 092 } 093 } 094 095 @Override 096 public void close() { 097 writeHeaders(); 098 } 099 100 private void writeHeaders() { 101 if (!this.headersWritten) { 102 getHeaders().forEach((headerName, headerValues) -> { 103 for (String headerValue : headerValues) { 104 this.servletResponse.addHeader(headerName, headerValue); 105 } 106 }); 107 // HttpServletResponse exposes some headers as properties: we should include those if not already present 108 if (this.servletResponse.getContentType() == null && this.headers.getContentType() != null) { 109 this.servletResponse.setContentType(this.headers.getContentType().toString()); 110 } 111 if (this.servletResponse.getCharacterEncoding() == null && this.headers.getContentType() != null && 112 this.headers.getContentType().getCharset() != null) { 113 this.servletResponse.setCharacterEncoding(this.headers.getContentType().getCharset().name()); 114 } 115 this.headersWritten = true; 116 } 117 } 118 119 120 /** 121 * Extends HttpHeaders with the ability to look up headers already present in 122 * the underlying HttpServletResponse. 123 * 124 * <p>The intent is merely to expose what is available through the HttpServletResponse 125 * i.e. the ability to look up specific header values by name. All other 126 * map-related operations (e.g. iteration, removal, etc) apply only to values 127 * added directly through HttpHeaders methods. 128 * 129 * @since 4.0.3 130 */ 131 private class ServletResponseHttpHeaders extends HttpHeaders { 132 133 private static final long serialVersionUID = 3410708522401046302L; 134 135 @Override 136 public boolean containsKey(Object key) { 137 return (super.containsKey(key) || (get(key) != null)); 138 } 139 140 @Override 141 @Nullable 142 public String getFirst(String headerName) { 143 String value = servletResponse.getHeader(headerName); 144 if (value != null) { 145 return value; 146 } 147 else { 148 return super.getFirst(headerName); 149 } 150 } 151 152 @Override 153 public List<String> get(Object key) { 154 Assert.isInstanceOf(String.class, key, "Key must be a String-based header name"); 155 156 Collection<String> values1 = servletResponse.getHeaders((String) key); 157 if (headersWritten) { 158 return new ArrayList<>(values1); 159 } 160 boolean isEmpty1 = CollectionUtils.isEmpty(values1); 161 162 List<String> values2 = super.get(key); 163 boolean isEmpty2 = CollectionUtils.isEmpty(values2); 164 165 if (isEmpty1 && isEmpty2) { 166 return null; 167 } 168 169 List<String> values = new ArrayList<>(); 170 if (!isEmpty1) { 171 values.addAll(values1); 172 } 173 if (!isEmpty2) { 174 values.addAll(values2); 175 } 176 return values; 177 } 178 } 179 180}