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Adjust WebFlux behavior for @RequestPart List<T>

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List<T> support was added relatively late, incorrectly decoding each
part to T which means no way to decode a single part to List<T> and
thatis the most common case (vs multipart parts with the same name).
This behavior was further misaligned with Spring MVC as well as with
the behavior for T[].

Closes gh-22973
This commit is contained in:
Rossen Stoyanchev
2020-06-20 08:33:26 +01:00
parent 01fa923e96
commit ff9daa9377
2 changed files with 94 additions and 84 deletions
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119
spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/RequestPartMethodArgumentResolver.java
View File

@@ -1,5 +1,5 @@
/*
* Copyright 2002-2019 the original author or authors.
* Copyright 2002-2020 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.
@@ -16,6 +16,7 @@
package org.springframework.web.reactive.result.method.annotation;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
@@ -33,6 +34,7 @@ import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpRequestDecorator;
import org.springframework.lang.Nullable;
import org.springframework.util.CollectionUtils;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.RequestPart;
import org.springframework.web.reactive.BindingContext;
import org.springframework.web.server.ServerWebExchange;
@@ -69,77 +71,86 @@ public class RequestPartMethodArgumentResolver extends AbstractMessageReaderArgu
RequestPart requestPart = parameter.getParameterAnnotation(RequestPart.class);
boolean isRequired = (requestPart == null || requestPart.required());
String name = getPartName(parameter, requestPart);
Class<?> paramType = parameter.getParameterType();
Flux<Part> partValues = getPartValues(parameter, requestPart, isRequired, exchange);
Flux<Part> parts = exchange.getMultipartData()
if (Part.class.isAssignableFrom(paramType)) {
return partValues.next().cast(Object.class);
}
if (Collection.class.isAssignableFrom(paramType) || List.class.isAssignableFrom(paramType)) {
MethodParameter elementType = parameter.nested();
if (Part.class.isAssignableFrom(elementType.getNestedParameterType())) {
return partValues.collectList().cast(Object.class);
}
else {
return partValues.next()
.flatMap(part -> decode(part, parameter, bindingContext, exchange, isRequired))
.defaultIfEmpty(Collections.emptyList());
}
}
ReactiveAdapter adapter = getAdapterRegistry().getAdapter(paramType);
if (adapter == null) {
return partValues.next().flatMap(part ->
decode(part, parameter, bindingContext, exchange, isRequired));
}
MethodParameter elementType = parameter.nested();
if (Part.class.isAssignableFrom(elementType.getNestedParameterType())) {
return Mono.just(adapter.fromPublisher(partValues));
}
Flux<?> flux = partValues.flatMap(part -> decode(part, elementType, bindingContext, exchange, isRequired));
return Mono.just(adapter.fromPublisher(flux));
}
public Flux<Part> getPartValues(
MethodParameter parameter, @Nullable RequestPart requestPart, boolean isRequired,
ServerWebExchange exchange) {
String name = getPartName(parameter, requestPart);
return exchange.getMultipartData()
.flatMapIterable(map -> {
List<Part> list = map.get(name);
if (CollectionUtils.isEmpty(list)) {
if (isRequired) {
throw getMissingPartException(name, parameter);
String reason = "Required request part '" + name + "' is not present";
throw new ServerWebInputException(reason, parameter);
}
return Collections.emptyList();
}
return list;
});
if (Part.class.isAssignableFrom(parameter.getParameterType())) {
return parts.next().cast(Object.class);
}
if (List.class.isAssignableFrom(parameter.getParameterType())) {
MethodParameter elementType = parameter.nested();
if (Part.class.isAssignableFrom(elementType.getNestedParameterType())) {
return parts.collectList().cast(Object.class);
}
else {
return decodePartValues(parts, elementType, bindingContext, exchange, isRequired)
.collectList().cast(Object.class);
}
}
ReactiveAdapter adapter = getAdapterRegistry().getAdapter(parameter.getParameterType());
if (adapter != null) {
MethodParameter elementType = parameter.nested();
return Mono.just(adapter.fromPublisher(
Part.class.isAssignableFrom(elementType.getNestedParameterType()) ?
parts : decodePartValues(parts, elementType, bindingContext, exchange, isRequired)));
}
return decodePartValues(parts, parameter, bindingContext, exchange, isRequired)
.next().cast(Object.class);
}
private String getPartName(MethodParameter methodParam, @Nullable RequestPart requestPart) {
String partName = (requestPart != null ? requestPart.name() : "");
if (partName.isEmpty()) {
partName = methodParam.getParameterName();
if (partName == null) {
throw new IllegalArgumentException("Request part name for argument type [" +
methodParam.getNestedParameterType().getName() +
"] not specified, and parameter name information not found in class file either.");
}
String name = null;
if (requestPart != null) {
name = requestPart.name();
}
return partName;
if (StringUtils.isEmpty(name)) {
name = methodParam.getParameterName();
}
if (StringUtils.isEmpty(name)) {
throw new IllegalArgumentException("Request part name for argument type [" +
methodParam.getNestedParameterType().getName() +
"] not specified, and parameter name information not found in class file either.");
}
return name;
}
private ServerWebInputException getMissingPartException(String name, MethodParameter param) {
String reason = "Required request part '" + name + "' is not present";
return new ServerWebInputException(reason, param);
}
private Flux<?> decodePartValues(Flux<Part> parts, MethodParameter elementType, BindingContext bindingContext,
@SuppressWarnings("unchecked")
private <T> Mono<T> decode(
Part part, MethodParameter elementType, BindingContext bindingContext,
ServerWebExchange exchange, boolean isRequired) {
return parts.flatMap(part -> {
ServerHttpRequest partRequest = new PartServerHttpRequest(exchange.getRequest(), part);
ServerWebExchange partExchange = exchange.mutate().request(partRequest).build();
if (logger.isDebugEnabled()) {
logger.debug(exchange.getLogPrefix() + "Decoding part '" + part.name() + "'");
}
return readBody(elementType, isRequired, bindingContext, partExchange);
});
ServerHttpRequest partRequest = new PartServerHttpRequest(exchange.getRequest(), part);
ServerWebExchange partExchange = exchange.mutate().request(partRequest).build();
if (logger.isDebugEnabled()) {
logger.debug(exchange.getLogPrefix() + "Decoding part '" + part.name() + "'");
}
return (Mono<T>) readBody(elementType, isRequired, bindingContext, partExchange);
}