/*
* Copyright 2002-2017 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.http.codec;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import org.springframework.core.ResolvableType;
import org.springframework.core.codec.Decoder;
import org.springframework.http.HttpMessage;
import org.springframework.http.MediaType;
import org.springframework.http.ReactiveHttpInputMessage;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.util.Assert;
/**
* {@code HttpMessageReader} that wraps and delegates to a {@link Decoder}.
*
* <p>Also a {@code HttpMessageReader} that pre-resolves decoding hints
* from the extra information available on the server side such as the request
* or controller method parameter annotations.
*
* @author Arjen Poutsma
* @author Sebastien Deleuze
* @author Rossen Stoyanchev
* @since 5.0
*/
public class DecoderHttpMessageReader<T> implements HttpMessageReader<T> {
private final Decoder<T> decoder;
private final List<MediaType> mediaTypes;
/**
* Create an instance wrapping the given {@link Decoder}.
*/
public DecoderHttpMessageReader(Decoder<T> decoder) {
Assert.notNull(decoder, "Decoder is required");
this.decoder = decoder;
this.mediaTypes = MediaType.asMediaTypes(decoder.getDecodableMimeTypes());
}
/**
* Return the {@link Decoder} of this reader.
*/
public Decoder<T> getDecoder() {
return this.decoder;
}
@Override
public List<MediaType> getReadableMediaTypes() {
return this.mediaTypes;
}
@Override
public boolean canRead(ResolvableType elementType, MediaType mediaType) {
return this.decoder.canDecode(elementType, mediaType);
}
@Override
public Flux<T> read(ResolvableType elementType, ReactiveHttpInputMessage message, Map<String, Object> hints) {
MediaType contentType = getContentType(message);
return this.decoder.decode(message.getBody(), elementType, contentType, hints);
}
@Override
public Mono<T> readMono(ResolvableType elementType, ReactiveHttpInputMessage message, Map<String, Object> hints) {
MediaType contentType = getContentType(message);
return this.decoder.decodeToMono(message.getBody(), elementType, contentType, hints);
}
private MediaType getContentType(HttpMessage inputMessage) {
MediaType contentType = inputMessage.getHeaders().getContentType();
return (contentType != null ? contentType : MediaType.APPLICATION_OCTET_STREAM);
}
// Server-side only...
@Override
public Flux<T> read(ResolvableType actualType, ResolvableType elementType,
ServerHttpRequest request, ServerHttpResponse response, Map<String, Object> hints) {
Map<String, Object> allHints = new HashMap<>(4);
allHints.putAll(getReadHints(actualType, elementType, request, response));
allHints.putAll(hints);
return read(elementType, request, allHints);
}
@Override
public Mono<T> readMono(ResolvableType actualType, ResolvableType elementType,
ServerHttpRequest request, ServerHttpResponse response, Map<String, Object> hints) {
Map<String, Object> allHints = new HashMap<>(4);
allHints.putAll(getReadHints(actualType, elementType, request, response));
allHints.putAll(hints);
return readMono(elementType, request, allHints);
}
/**
* Get additional hints for decoding for example based on the server request
* or annotations from controller method parameters. By default, delegate to
* the decoder if it is an instance of {@link HttpMessageDecoder}.
*/
protected Map<String, Object> getReadHints(ResolvableType streamType,
ResolvableType elementType, ServerHttpRequest request, ServerHttpResponse response) {
if (this.decoder instanceof HttpMessageDecoder) {
HttpMessageDecoder<?> httpDecoder = (HttpMessageDecoder<?>) this.decoder;
return httpDecoder.getDecodeHints(streamType, elementType, request, response);
}
return Collections.emptyMap();
}
}