org.springframework.http.client.MultipartBodyBuilder Maven / Gradle / Ivy
/*
* Copyright 2002-2023 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.client;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.function.Consumer;
import org.reactivestreams.Publisher;
import org.springframework.core.ParameterizedTypeReference;
import org.springframework.core.ResolvableType;
import org.springframework.core.ResolvableTypeProvider;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.codec.multipart.Part;
import org.springframework.lang.NonNull;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;
/**
* Prepare the body of a multipart request, resulting in a
* {@code MultiValueMap}. Parts may be concrete values or
* via asynchronous types such as Reactor {@code Mono}, {@code Flux}, and
* others registered in the
* {@link org.springframework.core.ReactiveAdapterRegistry ReactiveAdapterRegistry}.
*
* This builder is intended to POST {@code multipart/form-data} using the reactive
* {@link org.springframework.web.reactive.function.client.WebClient WebClient}.
* For multipart requests with the {@code RestTemplate}, simply create and
* populate a {@code MultiValueMap} as shown in the Javadoc for
* {@link org.springframework.http.converter.FormHttpMessageConverter FormHttpMessageConverter}
* and in the
* reference docs.
*
* Below are examples of using this builder:
*
*
* // Add form field
* MultipartBodyBuilder builder = new MultipartBodyBuilder();
* builder.part("form field", "form value").header("foo", "bar");
*
* // Add file part
* Resource image = new ClassPathResource("image.jpg");
* builder.part("image", image).header("foo", "bar");
*
* // Add content (e.g. JSON)
* Account account = ...
* builder.part("account", account).header("foo", "bar");
*
* // Add content from Publisher
* Mono<Account> accountMono = ...
* builder.asyncPart("account", accountMono).header("foo", "bar");
*
* // Build and use
* MultiValueMap<String, HttpEntity<?>> multipartBody = builder.build();
*
* Mono<Void> result = webClient.post()
* .uri("...")
* .bodyValue(multipartBody)
* .retrieve()
* .bodyToMono(Void.class)
*
*
* @author Arjen Poutsma
* @author Rossen Stoyanchev
* @author Sam Brannen
* @since 5.0.2
* @see RFC 7578
*/
public final class MultipartBodyBuilder {
private final LinkedMultiValueMap parts = new LinkedMultiValueMap<>();
/**
* Creates a new, empty instance of the {@code MultipartBodyBuilder}.
*/
public MultipartBodyBuilder() {
}
/**
* Add a part where the Object may be:
*
* - String -- form field
*
- {@link org.springframework.core.io.Resource Resource} -- file part
*
- Object -- content to be encoded (e.g. to JSON)
*
- {@link HttpEntity} -- part content and headers although generally it's
* easier to add headers through the returned builder
*
- {@link Part} -- a part from a server request
*
* @param name the name of the part to add
* @param part the part data
* @return builder that allows for further customization of part headers
*/
public PartBuilder part(String name, Object part) {
return part(name, part, null);
}
/**
* Variant of {@link #part(String, Object)} that also accepts a MediaType.
* @param name the name of the part to add
* @param part the part data
* @param contentType the media type to help with encoding the part
* @return builder that allows for further customization of part headers
*/
public PartBuilder part(String name, Object part, @Nullable MediaType contentType) {
Assert.hasLength(name, "'name' must not be empty");
Assert.notNull(part, "'part' must not be null");
if (part instanceof Part partObject) {
PartBuilder builder = asyncPart(name, partObject.content(), DataBuffer.class);
if (!partObject.headers().isEmpty()) {
builder.headers(headers -> {
headers.putAll(partObject.headers());
String filename = headers.getContentDisposition().getFilename();
// reset to parameter name
headers.setContentDispositionFormData(name, filename);
});
}
if (contentType != null) {
builder.contentType(contentType);
}
return builder;
}
if (part instanceof PublisherEntity publisherEntity) {
PublisherPartBuilder builder = new PublisherPartBuilder<>(name, publisherEntity);
if (contentType != null) {
builder.contentType(contentType);
}
this.parts.add(name, builder);
return builder;
}
Object partBody;
HttpHeaders partHeaders = null;
if (part instanceof HttpEntity httpEntity) {
partBody = httpEntity.getBody();
partHeaders = new HttpHeaders();
partHeaders.putAll(httpEntity.getHeaders());
}
else {
partBody = part;
}
if (partBody instanceof Publisher) {
throw new IllegalArgumentException("""
Use asyncPart(String, Publisher, Class) \
or asyncPart(String, Publisher, ParameterizedTypeReference) \
or MultipartBodyBuilder.PublisherEntity""");
}
DefaultPartBuilder builder = new DefaultPartBuilder(name, partHeaders, partBody);
if (contentType != null) {
builder.contentType(contentType);
}
this.parts.add(name, builder);
return builder;
}
/**
* Add a part from {@link Publisher} content.
* @param name the name of the part to add
* @param publisher a Publisher of content for the part
* @param elementClass the type of elements contained in the publisher
* @return builder that allows for further customization of part headers
*/
public > PartBuilder asyncPart(String name, P publisher, Class elementClass) {
Assert.hasLength(name, "'name' must not be empty");
Assert.notNull(publisher, "'publisher' must not be null");
Assert.notNull(elementClass, "'elementClass' must not be null");
PublisherPartBuilder builder = new PublisherPartBuilder<>(name, null, publisher, elementClass);
this.parts.add(name, builder);
return builder;
}
/**
* Variant of {@link #asyncPart(String, Publisher, Class)} with a
* {@link ParameterizedTypeReference} for the element type information.
* @param name the name of the part to add
* @param publisher the part contents
* @param typeReference the type of elements contained in the publisher
* @return builder that allows for further customization of part headers
*/
public > PartBuilder asyncPart(
String name, P publisher, ParameterizedTypeReference typeReference) {
Assert.hasLength(name, "'name' must not be empty");
Assert.notNull(publisher, "'publisher' must not be null");
Assert.notNull(typeReference, "'typeReference' must not be null");
PublisherPartBuilder builder = new PublisherPartBuilder<>(name, null, publisher, typeReference);
this.parts.add(name, builder);
return builder;
}
/**
* Return a {@code MultiValueMap} with the configured parts.
*/
public MultiValueMap> build() {
MultiValueMap> result = new LinkedMultiValueMap<>(this.parts.size());
for (Map.Entry> entry : this.parts.entrySet()) {
for (DefaultPartBuilder builder : entry.getValue()) {
HttpEntity entity = builder.build();
result.add(entry.getKey(), entity);
}
}
return result;
}
/**
* Builder that allows for further customization of part headers.
*/
public interface PartBuilder {
/**
* Set the {@linkplain MediaType media type} of the part.
* @param contentType the content type
* @since 5.2
* @see HttpHeaders#setContentType(MediaType)
*/
PartBuilder contentType(MediaType contentType);
/**
* Set the filename parameter for a file part. This should not be
* necessary with {@link org.springframework.core.io.Resource Resource}
* based parts that expose a filename but may be useful for
* {@link Publisher} parts.
* @param filename the filename to set on the Content-Disposition
* @since 5.2
*/
PartBuilder filename(String filename);
/**
* Add part header values.
* @param headerName the part header name
* @param headerValues the part header value(s)
* @return this builder
* @see HttpHeaders#addAll(String, List)
*/
PartBuilder header(String headerName, String... headerValues);
/**
* Manipulate the part headers through the given consumer.
* @param headersConsumer consumer to manipulate the part headers with
* @return this builder
*/
PartBuilder headers(Consumer headersConsumer);
}
private static class DefaultPartBuilder implements PartBuilder {
private final String name;
@Nullable
protected HttpHeaders headers;
@Nullable
protected final Object body;
public DefaultPartBuilder(String name, @Nullable HttpHeaders headers, @Nullable Object body) {
this.name = name;
this.headers = headers;
this.body = body;
}
@Override
public PartBuilder contentType(MediaType contentType) {
initHeadersIfNecessary().setContentType(contentType);
return this;
}
@Override
public PartBuilder filename(String filename) {
initHeadersIfNecessary().setContentDispositionFormData(this.name, filename);
return this;
}
@Override
public PartBuilder header(String headerName, String... headerValues) {
initHeadersIfNecessary().addAll(headerName, Arrays.asList(headerValues));
return this;
}
@Override
public PartBuilder headers(Consumer headersConsumer) {
headersConsumer.accept(initHeadersIfNecessary());
return this;
}
private HttpHeaders initHeadersIfNecessary() {
if (this.headers == null) {
this.headers = new HttpHeaders();
}
return this.headers;
}
public HttpEntity build() {
return new HttpEntity<>(this.body, this.headers);
}
}
private static class PublisherPartBuilder> extends DefaultPartBuilder {
private final ResolvableType resolvableType;
public PublisherPartBuilder(String name, @Nullable HttpHeaders headers, P body, Class elementClass) {
super(name, headers, body);
this.resolvableType = ResolvableType.forClass(elementClass);
}
public PublisherPartBuilder(String name, @Nullable HttpHeaders headers, P body,
ParameterizedTypeReference typeRef) {
super(name, headers, body);
this.resolvableType = ResolvableType.forType(typeRef);
}
public PublisherPartBuilder(String name, PublisherEntity other) {
super(name, other.getHeaders(), other.getBody());
this.resolvableType = other.getResolvableType();
}
@Override
@SuppressWarnings("unchecked")
public HttpEntity build() {
P publisher = (P) this.body;
Assert.state(publisher != null, "Publisher must not be null");
return new PublisherEntity<>(this.headers, publisher, this.resolvableType);
}
}
/**
* Specialization of {@link HttpEntity} for use with a
* {@link Publisher}-based body, for which we also need to keep track of
* the element type.
* @param the type contained in the publisher
* @param the publisher
*/
static final class PublisherEntity> extends HttpEntity
implements ResolvableTypeProvider {
private final ResolvableType resolvableType;
PublisherEntity(
@Nullable MultiValueMap headers, P publisher, ResolvableType resolvableType) {
super(publisher, headers);
Assert.notNull(publisher, "'publisher' must not be null");
Assert.notNull(resolvableType, "'resolvableType' must not be null");
this.resolvableType = resolvableType;
}
/**
* Return the element type for the {@code Publisher} body.
*/
@Override
@NonNull
public ResolvableType getResolvableType() {
return this.resolvableType;
}
}
}