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Spring BFF/bff/auth/serialisers/RedisSerialiser.kt

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+package com.example.bff.auth.serialisers
+
+import com.fasterxml.jackson.databind.ObjectMapper
+import org.springframework.beans.factory.BeanClassLoaderAware
+import org.springframework.context.annotation.Bean
+import org.springframework.context.annotation.Configuration
+import org.springframework.data.redis.connection.ReactiveRedisConnectionFactory
+import org.springframework.data.redis.core.ReactiveRedisTemplate
+import org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer
+import org.springframework.data.redis.serializer.RedisSerializationContext
+import org.springframework.data.redis.serializer.RedisSerializer
+import org.springframework.data.redis.serializer.StringRedisSerializer
+import org.springframework.security.jackson2.SecurityJackson2Modules
+import org.springframework.security.oauth2.core.endpoint.OAuth2AuthorizationRequest
+
+/**********************************************************************************************************************/
+/**************************************************** SERIALISERS *****************************************************/
+/**********************************************************************************************************************/
+
+// more here:
+// https://docs.spring.io/spring-session/reference/configuration/reactive-redis-indexed.html
+
+@Configuration
+internal class RedisSerialiser : BeanClassLoaderAware {
+
+    private var loader: ClassLoader? = null
+
+    /**
+     * Note that the bean name for this bean is intentionally
+     * {@code springSessionDefaultRedisSerializer}. It must be named this way to override
+     * the default {@link RedisSerializer} used by Spring Session.
+     */
+    @Bean
+    // setting a custom session serialiser for Redis
+    fun springSessionDefaultRedisSerializer(): RedisSerializer<Any> {
+        return object : GenericJackson2JsonRedisSerializer(objectMapper()) {
+            override fun serialize(value: Any?): ByteArray {
+                println("Serializing: $value")
+                return super.serialize(value)
+            }
+
+            override fun deserialize(bytes: ByteArray?): Any {
+                if (bytes !== null && bytes.isNotEmpty()) {
+                    val result = super.deserialize(bytes)
+                    return result
+                }
+                println("Deserialization: Received null or empty byte array")
+                return Any()
+            }
+        }
+    }
+
+    /**
+     * Customized {@link ObjectMapper} to add mix-in for class that doesn't have default
+     * constructors.
+     * @return the {@link ObjectMapper} to use
+     */
+    private fun objectMapper(): ObjectMapper {
+        val mapper = ObjectMapper()
+
+        // register modules for security if needed
+        mapper.registerModules(SecurityJackson2Modules.getModules(loader))
+
+        return mapper
+    }
+
+    /*
+     * @see
+     * org.springframework.beans.factory.BeanClassLoaderAware#setBeanClassLoader(java.lang.ClassLoader)
+     */
+    override fun setBeanClassLoader(classLoader: ClassLoader) {
+        this.loader = classLoader
+    }
+
+    @Bean
+    // setting a custom OAuth2AuthorizationRequest serializer for Redis
+    fun oauth2AuthorizationRequestRedisSerializer(objectMapper: ObjectMapper): RedisSerializer<OAuth2AuthorizationRequest> {
+        return object : RedisSerializer<OAuth2AuthorizationRequest> {
+            override fun serialize(value: OAuth2AuthorizationRequest?): ByteArray {
+                println("Serializing: $value")
+                val bytes = objectMapper.writeValueAsBytes(value)
+                return bytes
+            }
+
+            override fun deserialize(bytes: ByteArray?): OAuth2AuthorizationRequest? {
+                println("Deserializing bytes: ${bytes?.joinToString(", ") { String.format("%02X", it) }}")
+                if (bytes !== null && bytes.isNotEmpty()) {
+                    val result = objectMapper.readValue(bytes, OAuth2AuthorizationRequest::class.java)
+                    println("Deserialized OAuth2AuthorizationRequest: $result")
+                    return result
+                }
+                println("Deserialization: Received null or empty byte array")
+                return null
+            }
+        }
+    }
+
+}
+
+/**********************************************************************************************************************/
+/**************************************************** END OF KOTLIN ***************************************************/
+/**********************************************************************************************************************/