Added test for setting headers through extensions and DgsExecutionResult

graphql-dgs-spring-graphql/src/main/kotlin/com/netflix/graphql/dgs/springgraphql/autoconfig/DgsSpringGraphQLAutoConfiguration.kt

@@ -512,7 +512,17 @@ open class DgsSpringGraphQLAutoConfiguration(
             graphQLContextContributors,
         )
 
+    /**
+     * Backward compatibility for setting response headers through a "dgs-response-headers" field in extensions, or using DgsExecutionResult.
+     * While this can easily be done through a custom WebGraphQlInterceptor, this bean provides backward compatibility with older code.
+     */
     @Bean
+    @ConditionalOnProperty(
+        prefix = "${AUTO_CONF_PREFIX}.dgs-response-headers",
+        name = ["enabled"],
+        havingValue = "true",
+        matchIfMissing = true,
+    )
     open fun dgsHeadersInterceptor(): WebGraphQlInterceptor =
         WebGraphQlInterceptor { request, chain ->
             chain.next(request).doOnNext { response: WebGraphQlResponse ->

graphql-dgs-spring-graphql/src/test/kotlin/com/netflix/graphql/dgs/springgraphql/autoconfig/DgsHeadersSmokeTest.kt

@@ -0,0 +1,123 @@
+/*
+ * Copyright 2025 Netflix, Inc.
+ *
+ * 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
+ *
+ *    http://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 com.netflix.graphql.dgs.springgraphql.autoconfig
+
+import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
+import com.netflix.graphql.dgs.DgsComponent
+import com.netflix.graphql.dgs.DgsExecutionResult
+import com.netflix.graphql.dgs.DgsQuery
+import graphql.ExecutionResult
+import graphql.execution.instrumentation.InstrumentationState
+import graphql.execution.instrumentation.SimplePerformantInstrumentation
+import graphql.execution.instrumentation.parameters.InstrumentationExecutionParameters
+import org.junit.jupiter.api.Test
+import org.springframework.beans.factory.annotation.Autowired
+import org.springframework.boot.autoconfigure.graphql.GraphQlAutoConfiguration
+import org.springframework.boot.autoconfigure.graphql.servlet.GraphQlWebMvcAutoConfiguration
+import org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration
+import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc
+import org.springframework.boot.test.context.SpringBootTest
+import org.springframework.boot.test.context.TestConfiguration
+import org.springframework.http.HttpHeaders
+import org.springframework.http.MediaType
+import org.springframework.stereotype.Component
+import org.springframework.test.web.servlet.MockMvc
+import org.springframework.test.web.servlet.post
+import java.util.concurrent.CompletableFuture
+
+@SpringBootTest(
+    classes = [
+        DgsHeadersSmokeTest.TestApp::class,
+        DgsSpringGraphQLAutoConfiguration::class,
+        GraphQlAutoConfiguration::class,
+        GraphQlWebMvcAutoConfiguration::class,
+        WebMvcAutoConfiguration::class,
+    ],
+    properties = [
+        "dgs.graphql.schema-locations=classpath:/dgs-spring-graphql-smoke-test.graphqls"]
+)
+@AutoConfigureMockMvc
+class DgsHeadersSmokeTest {
+
+    @Autowired
+    lateinit var mockMvc: MockMvc
+
+    @Test
+    fun `Response headers can be set by using DgsExecutionResult`() {
+        val query =
+            """
+            query {
+                dgsField
+            }
+            """.trimIndent()
+
+        data class GraphQlRequest(
+            val query: String,
+        )
+
+        mockMvc
+            .post("/graphql") {
+                content = jacksonObjectMapper().writeValueAsString(GraphQlRequest(query))
+                accept = MediaType.APPLICATION_JSON
+                contentType = MediaType.APPLICATION_JSON
+            }.andExpect {
+                status { isOk() }
+                header { string("dgsexecutionresultheader", "set from DgsExecutionResult") }
+                header { string("extensionheader", "set from extensions") }
+            }
+    }
+
+    @TestConfiguration
+    open class TestApp {
+        @DgsComponent
+        open class DgsTestDatafetcher {
+            @DgsQuery
+            fun dgsField(): String = "test from DGS"
+
+            @Component
+            open class MyIntrospection : SimplePerformantInstrumentation() {
+                override fun instrumentExecutionResult(
+                    executionResult: ExecutionResult,
+                    parameters: InstrumentationExecutionParameters,
+                    state: InstrumentationState?
+                ): CompletableFuture<ExecutionResult> {
+                    val headers = HttpHeaders()
+                    headers.add("dgsexecutionresultheader", "set from DgsExecutionResult")
+
+
+                    val extensionHeaders = HttpHeaders()
+                    extensionHeaders.add("extensionheader", "set from extensions")
+                    val updatedExecutionResult = executionResult.transform { r ->
+                        r.extensions(
+                            mapOf(
+                                Pair(
+                                    "dgs-response-headers",
+                                    extensionHeaders
+                                )
+                            )
+                        )
+                    }
+
+                    return CompletableFuture.completedFuture(
+                        DgsExecutionResult.builder().executionResult(updatedExecutionResult).headers(headers).build()
+                    )
+                }
+            }
+        }
+    }
+
+}

graphql-dgs/src/main/kotlin/com/netflix/graphql/dgs/DgsExecutionResult.kt

@@ -24,7 +24,7 @@ import org.springframework.http.HttpStatus
 class DgsExecutionResult(
     private val executionResult: ExecutionResult,
     val headers: HttpHeaders,
-    val status: HttpStatus,
+    val status: HttpStatus = HttpStatus.OK,
 ) : ExecutionResult by executionResult {
     /**
      * Facilitate the construction of a [DgsExecutionResult] instance.