org.springframework.web.client.IntrospectingClientHttpResponse 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.web.client;
import java.io.IOException;
import java.io.InputStream;
import java.io.PushbackInputStream;
import org.springframework.http.HttpStatus;
import org.springframework.http.HttpStatusCode;
import org.springframework.http.client.ClientHttpResponse;
import org.springframework.lang.Nullable;
/**
* Implementation of {@link ClientHttpResponse} that can not only check if
* the response has a message body, but also if its length is 0 (i.e. empty)
* by actually reading the input stream.
*
* @author Brian Clozel
* @author Rossen Stoyanchev
* @since 4.1.5
* @see RFC 7230 Section 3.3.3
*/
class IntrospectingClientHttpResponse extends ClientHttpResponseDecorator {
@Nullable
private PushbackInputStream pushbackInputStream;
public IntrospectingClientHttpResponse(ClientHttpResponse response) {
super(response);
}
/**
* Indicates whether the response has a message body.
* Implementation returns {@code false} for:
*
* - a response status of {@code 1XX}, {@code 204} or {@code 304}
* - a {@code Content-Length} header of {@code 0}
*
* @return {@code true} if the response has a message body, {@code false} otherwise
* @throws IOException in case of I/O errors
*/
public boolean hasMessageBody() throws IOException {
HttpStatusCode statusCode = getStatusCode();
if (statusCode.is1xxInformational() || statusCode == HttpStatus.NO_CONTENT ||
statusCode == HttpStatus.NOT_MODIFIED) {
return false;
}
if (getHeaders().getContentLength() == 0) {
return false;
}
return true;
}
/**
* Indicates whether the response has an empty message body.
* Implementation tries to read the first bytes of the response stream:
*
* - if no bytes are available, the message body is empty
* - otherwise it is not empty and the stream is reset to its start for further reading
*
* @return {@code true} if the response has a zero-length message body, {@code false} otherwise
* @throws IOException in case of I/O errors
*/
@SuppressWarnings("ConstantConditions")
public boolean hasEmptyMessageBody() throws IOException {
InputStream body = getDelegate().getBody();
// Per contract body shouldn't be null, but check anyway..
if (body == null) {
return true;
}
if (body.markSupported()) {
body.mark(1);
if (body.read() == -1) {
return true;
}
else {
body.reset();
return false;
}
}
else {
this.pushbackInputStream = new PushbackInputStream(body);
int b = this.pushbackInputStream.read();
if (b == -1) {
return true;
}
else {
this.pushbackInputStream.unread(b);
return false;
}
}
}
@Override
public InputStream getBody() throws IOException {
return (this.pushbackInputStream != null ? this.pushbackInputStream : getDelegate().getBody());
}
}