org.springframework.http.server.ServletServerHttpResponse Maven / Gradle / Ivy
/*
* Copyright 2002-2022 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.Collections;
import java.util.List;
import jakarta.servlet.http.HttpServletResponse;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatusCode;
import org.springframework.http.MediaType;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
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 {
private final HttpServletResponse servletResponse;
private final HttpHeaders headers;
private boolean headersWritten = false;
private boolean bodyUsed = false;
@Nullable
private HttpHeaders readOnlyHeaders;
/**
* 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 = new ServletResponseHttpHeaders();
}
/**
* Return the {@code HttpServletResponse} this object is based on.
*/
public HttpServletResponse getServletResponse() {
return this.servletResponse;
}
@Override
public void setStatusCode(HttpStatusCode status) {
Assert.notNull(status, "HttpStatusCode must not be null");
this.servletResponse.setStatus(status.value());
}
@Override
public HttpHeaders getHeaders() {
if (this.readOnlyHeaders != null) {
return this.readOnlyHeaders;
}
else if (this.headersWritten) {
this.readOnlyHeaders = HttpHeaders.readOnlyHttpHeaders(this.headers);
return this.readOnlyHeaders;
}
else {
return 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) {
getHeaders().forEach((headerName, headerValues) -> {
for (String headerValue : headerValues) {
this.servletResponse.addHeader(headerName, headerValue);
}
});
// HttpServletResponse exposes some headers as properties: we should include those if not already present
MediaType contentTypeHeader = this.headers.getContentType();
if (this.servletResponse.getContentType() == null && contentTypeHeader != null) {
this.servletResponse.setContentType(contentTypeHeader.toString());
}
if (this.servletResponse.getCharacterEncoding() == null && contentTypeHeader != null &&
contentTypeHeader.getCharset() != null) {
this.servletResponse.setCharacterEncoding(contentTypeHeader.getCharset().name());
}
long contentLength = getHeaders().getContentLength();
if (contentLength != -1) {
this.servletResponse.setContentLengthLong(contentLength);
}
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 (for example, 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
@Nullable
public String getFirst(String headerName) {
if (headerName.equalsIgnoreCase(CONTENT_TYPE)) {
// Content-Type is written as an override so check super first
String value = super.getFirst(headerName);
return (value != null ? value : servletResponse.getContentType());
}
else {
String value = servletResponse.getHeader(headerName);
return (value != null ? value : super.getFirst(headerName));
}
}
@Override
@Nullable
public List get(Object key) {
Assert.isInstanceOf(String.class, key, "Key must be a String-based header name");
String headerName = (String) key;
if (headerName.equalsIgnoreCase(CONTENT_TYPE)) {
// Content-Type is written as an override so don't merge
String value = getFirst(headerName);
return (value != null ? Collections.singletonList(value) : null);
}
Collection values1 = servletResponse.getHeaders(headerName);
if (headersWritten) {
return new ArrayList<>(values1);
}
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;
}
}
}