feat: add support for creating entity with content in a single request

spring-content-rest/src/main/asciidoc/rest-entitycontent.adoc

@@ -0,0 +1,17 @@
+== Entity & Content
+
+=== The Collection Resource
+Spring Data REST exposes a collection resource named after the uncapitalized, pluralized version of the domain class the exported repository is handling.
+
+Spring Content REST extends this collection resource with a handler that consumes `multipart/form-data`.  This handler allows the creation of an entity
+and association of content in a single request.
+
+==== POST
+The POST method creates a new entity populating its properties from the form's parameters and associates content from the form's multipart files.
+
+Form parameters may include relationships.
+
+Multipart file names will be used to determine the content property to use in the set content operation.
+
+===== Support Media Types
+This POST method supports the `multipart/form-data` media type.

spring-content-rest/src/main/asciidoc/rest-index.adoc

@@ -25,6 +25,7 @@ include::rest-store.adoc[]
 
 include::rest-repository.adoc[]
 
+include::rest-entitycontent.adoc[leveloffset=+1]
 include::{spring-content-solr-docs}/solr-rest.adoc[leveloffset=+1]
 
 == Locking and Versioning

spring-content-rest/src/main/java/internal/org/springframework/content/rest/utils/ControllerUtils.java

@@ -3,14 +3,19 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Optional;
 
 import org.springframework.data.domain.Page;
 import org.springframework.data.rest.webmvc.PersistentEntityResourceAssembler;
 import org.springframework.data.web.PagedResourcesAssembler;
 import org.springframework.hateoas.CollectionModel;
 import org.springframework.hateoas.EntityModel;
 import org.springframework.hateoas.Link;
+import org.springframework.hateoas.RepresentationModel;
 import org.springframework.hateoas.server.core.EmbeddedWrappers;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
 import org.springframework.web.servlet.support.ServletUriComponentsBuilder;
 
 public final class ControllerUtils {
@@ -19,6 +24,15 @@ public final class ControllerUtils {
 
     private ControllerUtils() {}
 
+    public static <R extends RepresentationModel<?>> ResponseEntity<RepresentationModel<?>> toResponseEntity(HttpStatus status, HttpHeaders headers, Optional<R> resource) {
+        HttpHeaders hdrs = new HttpHeaders();
+        if (headers != null) {
+            hdrs.putAll(headers);
+        }
+
+        return new ResponseEntity((RepresentationModel)resource.orElse(null), hdrs, status);
+    }
+
     protected static CollectionModel<?> entitiesToResources(Page<Object> page,
             PagedResourcesAssembler<Object> prAssembler,
             PersistentEntityResourceAssembler assembler,

spring-content-rest/src/main/java/org/springframework/content/rest/config/HypermediaConfiguration.java

@@ -12,7 +12,7 @@
 import org.springframework.hateoas.server.RepresentationModelProcessor;
 
 @Configuration
-@Import(RestConfiguration.class)
+@Import({RestConfiguration.class})
 public class HypermediaConfiguration {
 
 	@Bean

spring-content-rest/src/main/java/org/springframework/data/rest/extensions/entitycontent/RepositoryEntityMultipartConfiguration.java

@@ -0,0 +1,22 @@
+package org.springframework.data.rest.extensions.entitycontent;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.data.rest.webmvc.config.RepositoryRestConfigurer;
+import org.springframework.http.converter.HttpMessageConverter;
+
+import java.util.List;
+
+@Configuration
+public class RepositoryEntityMultipartConfiguration {
+
+    @Bean
+    public RepositoryRestConfigurer entityMultipartHttpMessageConverterConfigurer() {
+        return new RepositoryRestConfigurer() {
+            public void configureHttpMessageConverters(List<HttpMessageConverter<?>> messageConverters) {
+                // Add your custom message converter to the list
+                messageConverters.add(new RepositoryEntityMultipartHttpMessageConverter(messageConverters));
+            }
+        };
+    }
+}

spring-content-rest/src/main/java/org/springframework/data/rest/extensions/entitycontent/RepositoryEntityMultipartController.java

@@ -0,0 +1,272 @@
+package org.springframework.data.rest.extensions.entitycontent;
+
+import internal.org.springframework.content.rest.contentservice.ContentStoreContentService;
+import internal.org.springframework.content.rest.controllers.BadRequestException;
+import internal.org.springframework.content.rest.controllers.MethodNotAllowedException;
+import internal.org.springframework.content.rest.controllers.resolvers.AssociativeStoreResourceResolver;
+import internal.org.springframework.content.rest.mappingcontext.ContentPropertyToExportedContext;
+import internal.org.springframework.content.rest.mappings.StoreByteRangeHttpRequestHandler;
+import internal.org.springframework.content.rest.utils.ControllerUtils;
+import internal.org.springframework.content.rest.utils.StoreUtils;
+import jakarta.servlet.http.HttpServletResponse;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.content.commons.mappingcontext.MappingContext;
+import org.springframework.content.commons.property.PropertyPath;
+import org.springframework.content.commons.repository.Store;
+import org.springframework.content.commons.storeservice.StoreInfo;
+import org.springframework.content.commons.storeservice.Stores;
+import org.springframework.content.rest.config.RestConfiguration;
+import org.springframework.core.io.InputStreamResource;
+import org.springframework.core.io.Resource;
+import org.springframework.data.repository.support.RepositoryInvokerFactory;
+import org.springframework.data.rest.core.mapping.ResourceType;
+import org.springframework.data.rest.core.support.SelfLinkProvider;
+import org.springframework.data.rest.webmvc.PersistentEntityResource;
+import org.springframework.data.rest.webmvc.PersistentEntityResourceAssembler;
+import org.springframework.data.rest.webmvc.RepositoryRestController;
+import org.springframework.data.rest.webmvc.RootResourceInformation;
+import org.springframework.data.rest.webmvc.config.RepositoryRestConfigurer;
+import org.springframework.hateoas.RepresentationModel;
+import org.springframework.hateoas.UriTemplate;
+import org.springframework.http.*;
+import org.springframework.util.MultiValueMap;
+import org.springframework.web.HttpRequestMethodNotSupportedException;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestHeader;
+import org.springframework.web.bind.annotation.ResponseBody;
+import org.springframework.web.context.request.NativeWebRequest;
+import org.springframework.web.multipart.MultipartFile;
+import org.springframework.web.multipart.MultipartHttpServletRequest;
+import org.springframework.web.util.UrlPathHelper;
+
+import java.io.IOException;
+import java.lang.reflect.InvocationTargetException;
+import java.security.Principal;
+import java.util.*;
+
+@RepositoryRestController
+public class RepositoryEntityMultipartController {
+
+    private static final String ENTITY_POST_MAPPING = "/{repository}";
+
+    private RestConfiguration restConfig;
+    private RepositoryInvokerFactory repoInvokerFactory;
+    private MappingContext mappingContext;
+    private ContentPropertyToExportedContext exportedMappingContext;
+    private StoreByteRangeHttpRequestHandler byteRangeRestRequestHandler;
+    private Stores stores;
+    private SelfLinkProvider selfLinkProvider;
+
+    @Autowired
+    public RepositoryEntityMultipartController(RestConfiguration restConfig, RepositoryInvokerFactory repoInvokerFactory, SelfLinkProvider selfLinkProvider, Stores stores, MappingContext mappingContext, ContentPropertyToExportedContext exportedMappingContext, StoreByteRangeHttpRequestHandler byteRangeRestRequestHandler, @Qualifier("entityMultipartHttpMessageConverterConfigurer") RepositoryRestConfigurer configurer) {
+        this.restConfig = restConfig;
+        this.repoInvokerFactory = repoInvokerFactory;
+        this.selfLinkProvider = selfLinkProvider;
+        this.stores = stores;
+        this.mappingContext = mappingContext;
+        this.exportedMappingContext = exportedMappingContext;
+        this.byteRangeRestRequestHandler = byteRangeRestRequestHandler;
+    }
+
+    @SuppressWarnings({ "rawtypes", "unchecked" })
+    @ResponseBody
+    @PostMapping(value = ENTITY_POST_MAPPING, consumes = "multipart/form-data")
+    public ResponseEntity<RepresentationModel<?>> createEntityAndContent(RootResourceInformation repoInfo, PersistentEntityResource payload, PersistentEntityResourceAssembler assembler, @PathVariable("repository") String repository, @RequestHeader HttpHeaders headers, MultipartHttpServletRequest req, HttpServletResponse resp)
+            throws IOException, MethodNotAllowedException, HttpRequestMethodNotSupportedException {
+
+        repoInfo.verifySupportedMethod(HttpMethod.POST, ResourceType.COLLECTION);
+
+        Class<?> domainType = repoInfo.getDomainType();
+
+        Object savedEntity = payload.getContent();
+
+        String pathInfo = new UrlPathHelper().getPathWithinApplication(req);
+        pathInfo = StoreUtils.storeLookupPath(pathInfo, restConfig.getBaseUri());
+
+        String[] pathSegments = pathInfo.split("/");
+        if (pathSegments.length < 2) {
+            throw new BadRequestException();
+        }
+
+        String store = pathSegments[1];
+
+        StoreInfo info = this.stores.getStore(Store.class, StoreUtils.withStorePath(store));
+        if (info != null) {
+            ContentStoreContentService service = new ContentStoreContentService(restConfig, info, repoInvokerFactory.getInvokerFor(domainType), mappingContext, exportedMappingContext, byteRangeRestRequestHandler);
+            MultiValueMap<String, MultipartFile> files = req.getMultiFileMap();
+            for (String path : files.keySet()) {
+                MultipartFile file = files.get(path).get(0);
+
+                Resource storeResource = new AssociativeStoreResourceResolver(mappingContext).resolve(new InternalWebRequest(req, resp), info, savedEntity, PropertyPath.from(file.getName()));
+
+                service.setContent(req, resp, headers, new InputStreamResource(file.getInputStream()), MediaType.parseMediaType(file.getContentType()), storeResource);
+            }
+        }
+
+        Optional<PersistentEntityResource> resource = Optional.ofNullable(assembler.toFullResource(savedEntity));
+        headers.setContentType(new MediaType("application", "hal+json"));
+
+        String selfLink = selfLinkProvider.createSelfLinkFor(savedEntity).withSelfRel().expand(new Object[0]).getHref();
+        resp.setHeader("Location", UriTemplate.of(selfLink).expand(new Object[0]).toString());
+
+        return ControllerUtils.toResponseEntity(HttpStatus.CREATED, headers, resource);
+    }
+
+    private static class InternalWebRequest implements NativeWebRequest {
+
+        private final MultipartHttpServletRequest req;
+        private final HttpServletResponse resp;
+
+        public InternalWebRequest(MultipartHttpServletRequest req, HttpServletResponse resp) {
+            this.req = req;
+            this.resp = resp;
+        }
+
+        @Override
+        public Object getNativeRequest() {
+            return req;
+        }
+
+        @Override
+        public Object getNativeResponse() {
+            return resp;
+        }
+
+        @Override
+        public <T> T getNativeRequest(Class<T> requiredType) {
+            return (T) req;
+        }
+
+        @Override
+        public <T> T getNativeResponse(Class<T> requiredType) {
+            return (T) resp;
+        }
+
+        @Override
+        public String getHeader(String headerName) {
+            return req.getHeader(headerName);
+        }
+
+        @Override
+        public String[] getHeaderValues(String headerName) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public Iterator<String> getHeaderNames() {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public String getParameter(String paramName) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public String[] getParameterValues(String paramName) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public Iterator<String> getParameterNames() {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public Map<String, String[]> getParameterMap() {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public Locale getLocale() {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public String getContextPath() {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public String getRemoteUser() {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public Principal getUserPrincipal() {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public boolean isUserInRole(String role) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public boolean isSecure() {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public boolean checkNotModified(long lastModifiedTimestamp) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public boolean checkNotModified(String etag) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public boolean checkNotModified(String etag, long lastModifiedTimestamp) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public String getDescription(boolean includeClientInfo) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public Object getAttribute(String name, int scope) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public void setAttribute(String name, Object value, int scope) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public void removeAttribute(String name, int scope) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public String[] getAttributeNames(int scope) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public void registerDestructionCallback(String name, Runnable callback, int scope) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public Object resolveReference(String key) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public String getSessionId() {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public Object getSessionMutex() {
+            throw new UnsupportedOperationException();
+        }
+    }
+}