org.springframework.http.server.ServletServerHttpResponse Maven / Gradle / Ivy
/*
* Copyright 2002-2016 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
*
* https://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.http.server;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import javax.servlet.http.HttpServletResponse;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
import org.springframework.util.CollectionUtils;
/**
* {@link ServerHttpResponse} implementation that is based on a {@link HttpServletResponse}.
*
* @author Arjen Poutsma
* @author Rossen Stoyanchev
* @since 3.0
*/
public class ServletServerHttpResponse implements ServerHttpResponse {
/** Checking for Servlet 3.0+ HttpServletResponse.getHeader(String) */
private static final boolean servlet3Present =
ClassUtils.hasMethod(HttpServletResponse.class, "getHeader", String.class);
private final HttpServletResponse servletResponse;
private final HttpHeaders headers;
private boolean headersWritten = false;
private boolean bodyUsed = false;
/**
* Construct a new instance of the ServletServerHttpResponse based on the given {@link HttpServletResponse}.
* @param servletResponse the servlet response
*/
public ServletServerHttpResponse(HttpServletResponse servletResponse) {
Assert.notNull(servletResponse, "HttpServletResponse must not be null");
this.servletResponse = servletResponse;
this.headers = (servlet3Present ? new ServletResponseHttpHeaders() : new HttpHeaders());
}
/**
* Return the {@code HttpServletResponse} this object is based on.
*/
public HttpServletResponse getServletResponse() {
return this.servletResponse;
}
@Override
public void setStatusCode(HttpStatus status) {
Assert.notNull(status, "HttpStatus must not be null");
this.servletResponse.setStatus(status.value());
}
@Override
public HttpHeaders getHeaders() {
return (this.headersWritten ? HttpHeaders.readOnlyHttpHeaders(this.headers) : this.headers);
}
@Override
public OutputStream getBody() throws IOException {
this.bodyUsed = true;
writeHeaders();
return this.servletResponse.getOutputStream();
}
@Override
public void flush() throws IOException {
writeHeaders();
if (this.bodyUsed) {
this.servletResponse.flushBuffer();
}
}
@Override
public void close() {
writeHeaders();
}
private void writeHeaders() {
if (!this.headersWritten) {
for (Map.Entry> entry : this.headers.entrySet()) {
String headerName = entry.getKey();
for (String headerValue : entry.getValue()) {
this.servletResponse.addHeader(headerName, headerValue);
}
}
// HttpServletResponse exposes some headers as properties: we should include those if not already present
if (this.servletResponse.getContentType() == null && this.headers.getContentType() != null) {
this.servletResponse.setContentType(this.headers.getContentType().toString());
}
if (this.servletResponse.getCharacterEncoding() == null && this.headers.getContentType() != null &&
this.headers.getContentType().getCharset() != null) {
this.servletResponse.setCharacterEncoding(this.headers.getContentType().getCharset().name());
}
this.headersWritten = true;
}
}
/**
* Extends HttpHeaders with the ability to look up headers already present in
* the underlying HttpServletResponse.
*
* The intent is merely to expose what is available through the HttpServletResponse
* i.e. the ability to look up specific header values by name. All other
* map-related operations (e.g. iteration, removal, etc) apply only to values
* added directly through HttpHeaders methods.
*
* @since 4.0.3
*/
private class ServletResponseHttpHeaders extends HttpHeaders {
private static final long serialVersionUID = 3410708522401046302L;
@Override
public boolean containsKey(Object key) {
return (super.containsKey(key) || (get(key) != null));
}
@Override
public String getFirst(String headerName) {
String value = servletResponse.getHeader(headerName);
if (value != null) {
return value;
}
else {
return super.getFirst(headerName);
}
}
@Override
public List get(Object key) {
Assert.isInstanceOf(String.class, key, "Key must be a String-based header name");
Collection values1 = servletResponse.getHeaders((String) key);
boolean isEmpty1 = CollectionUtils.isEmpty(values1);
List values2 = super.get(key);
boolean isEmpty2 = CollectionUtils.isEmpty(values2);
if (isEmpty1 && isEmpty2) {
return null;
}
List values = new ArrayList();
if (!isEmpty1) {
values.addAll(values1);
}
if (!isEmpty2) {
values.addAll(values2);
}
return values;
}
}
}