From 7b90887257e4500d9ced1901e98cce65d49936ce Mon Sep 17 00:00:00 2001
From: Lars Vierbergen <lars@vbgn.be>
Date: Tue, 5 Nov 2024 16:22:11 +0100
Subject: [PATCH] Make RepositoryEntityMultipartHttpMessageConverter resolve
 json HttpMessageConverter when it is being used.

In spring-data-rest 4.3.5, the logic has changed and now the entity
class is being passed to `canRead()` and `read()` instead of
`PersistentEntityResource`.

This means that a different converter can be triggered based on which
entity is being passed, so we need to select the correct HttpMessageConverter
at the point when we know the class that is being read.
This also allows users to configure their own specific
HttpMessageConverters for their entities.
---
 ...ryEntityMultipartHttpMessageConverter.java | 39 ++++++++++---------
 1 file changed, 20 insertions(+), 19 deletions(-)

diff --git a/spring-content-rest/src/main/java/org/springframework/data/rest/extensions/entitycontent/RepositoryEntityMultipartHttpMessageConverter.java b/spring-content-rest/src/main/java/org/springframework/data/rest/extensions/entitycontent/RepositoryEntityMultipartHttpMessageConverter.java
index 644d38d5d..f3ce8131a 100644
--- a/spring-content-rest/src/main/java/org/springframework/data/rest/extensions/entitycontent/RepositoryEntityMultipartHttpMessageConverter.java
+++ b/spring-content-rest/src/main/java/org/springframework/data/rest/extensions/entitycontent/RepositoryEntityMultipartHttpMessageConverter.java
@@ -1,13 +1,10 @@
 package org.springframework.data.rest.extensions.entitycontent;
 
 import com.fasterxml.jackson.annotation.JsonProperty;
-import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import org.springframework.beans.BeanWrapper;
 import org.springframework.beans.BeanWrapperImpl;
 import org.springframework.beans.InvalidPropertyException;
-import org.springframework.data.rest.webmvc.PersistentEntityResource;
-import org.springframework.hateoas.RepresentationModel;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpInputMessage;
 import org.springframework.http.HttpOutputMessage;
@@ -27,24 +24,28 @@
 
 public class RepositoryEntityMultipartHttpMessageConverter implements HttpMessageConverter<Object> {
 
-    private HttpMessageConverter converter = null;
+    private final List<HttpMessageConverter<?>> converters;
 
     public RepositoryEntityMultipartHttpMessageConverter(List<HttpMessageConverter<?>> messageConverters) {
-        for (HttpMessageConverter converter : messageConverters) {
-            if (converter.canRead(RepresentationModel.class, MediaType.APPLICATION_JSON)) {
-                this.converter = converter;
-                break;
+        this.converters = messageConverters;
+    }
+
+    private HttpMessageConverter<?> findReadConverter(Class clazz) {
+        for (HttpMessageConverter<?> converter : converters) {
+            if(converter.canRead(clazz, MediaType.APPLICATION_JSON)) {
+                return converter;
             }
         }
-        if (this.converter == null) {
-            throw new IllegalStateException("unable to resolve persistent entity resource message converter");
-        }
+        return null;
     }
 
     @Override
     public boolean canRead(Class clazz, MediaType mediaType) {
-        return PersistentEntityResource.class.equals(clazz) && mediaType != null
-                && mediaType.includes(MediaType.MULTIPART_FORM_DATA);
+        if(mediaType == null || !mediaType.includes(MediaType.MULTIPART_FORM_DATA)) {
+            return false;
+        }
+
+        return findReadConverter(clazz) != null;
     }
 
     @Override
@@ -57,11 +58,6 @@ public List<MediaType> getSupportedMediaTypes() {
         return Collections.singletonList(MediaType.MULTIPART_FORM_DATA);
     }
 
-    @Override
-    public List<MediaType> getSupportedMediaTypes(Class clazz) {
-        return HttpMessageConverter.super.getSupportedMediaTypes(clazz);
-    }
-
     @Override
     public Object read(Class clazz, HttpInputMessage inputMessage) throws IOException, HttpMessageNotReadableException {
         if (inputMessage instanceof ServletServerHttpRequest == false) {
@@ -93,7 +89,12 @@ public Object read(Class clazz, HttpInputMessage inputMessage) throws IOExceptio
         HttpHeaders headers = new HttpHeaders(inputMessage.getHeaders());
         headers.setContentType(MediaType.APPLICATION_JSON);
 
-        return this.converter.read(clazz, new HttpInputMessage() {
+        var converter = findReadConverter(clazz);
+        if(converter == null) {
+            throw new HttpMessageNotReadableException("No converter found for reading", inputMessage);
+        }
+
+        return converter.read(clazz, new HttpInputMessage() {
             @Override
             public InputStream getBody() throws IOException {
                 ObjectMapper mapper = new ObjectMapper();