Extend CorsDsl with CorsConfigurationSource property

Issue: gh-9314

config/src/main/kotlin/org/springframework/security/config/web/servlet/CorsDsl.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -18,15 +18,19 @@ package org.springframework.security.config.web.servlet
 
 import org.springframework.security.config.annotation.web.builders.HttpSecurity
 import org.springframework.security.config.annotation.web.configurers.CorsConfigurer
+import org.springframework.web.cors.CorsConfigurationSource
 
 /**
  * A Kotlin DSL to configure [HttpSecurity] CORS using idiomatic Kotlin code.
  *
  * @author Eleftheria Stein
  * @since 5.3
+ * @property configurationSource the [CorsConfigurationSource] to use.
  */
 @SecurityMarker
 class CorsDsl {
+    var configurationSource: CorsConfigurationSource? = null
+
     private var disabled = false
 
     /**
@@ -38,6 +42,7 @@ class CorsDsl {
 
     internal fun get(): (CorsConfigurer<HttpSecurity>) -> Unit {
         return { cors ->
+            configurationSource?.also { cors.configurationSource(configurationSource) }
             if (disabled) {
                 cors.disable()
             }

config/src/test/kotlin/org/springframework/security/config/web/servlet/CorsDslTests.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -67,7 +67,7 @@ class CorsDslTests {
 
     @Test
     fun `CORS when CORS configuration source bean then responds with CORS header`() {
-        this.spring.register(CorsCrossOriginConfig::class.java).autowire()
+        this.spring.register(CorsCrossOriginBeanConfig::class.java).autowire()
 
         this.mockMvc.get("/")
         {
@@ -79,7 +79,7 @@ class CorsDslTests {
 
     @EnableWebMvc
     @EnableWebSecurity
-    open class CorsCrossOriginConfig : WebSecurityConfigurerAdapter() {
+    open class CorsCrossOriginBeanConfig : WebSecurityConfigurerAdapter() {
         override fun configure(http: HttpSecurity) {
             http {
                 cors { }
@@ -135,4 +135,35 @@ class CorsDslTests {
             return source
         }
     }
+
+    @Test
+    fun `CORS when CORS configuration source dsl then responds with CORS header`() {
+        this.spring.register(CorsCrossOriginBeanConfig::class.java).autowire()
+
+        this.mockMvc.get("/")
+        {
+            header(HttpHeaders.ORIGIN, "https://example.com")
+        }.andExpect {
+            header { exists("Access-Control-Allow-Origin") }
+        }
+    }
+
+    @EnableWebMvc
+    @EnableWebSecurity
+    open class CorsCrossOriginSourceConfig : WebSecurityConfigurerAdapter() {
+        override fun configure(http: HttpSecurity) {
+            val source = UrlBasedCorsConfigurationSource()
+            val corsConfiguration = CorsConfiguration()
+            corsConfiguration.allowedOrigins = listOf("*")
+            corsConfiguration.allowedMethods = listOf(
+                    RequestMethod.GET.name,
+                    RequestMethod.POST.name)
+            source.registerCorsConfiguration("/**", corsConfiguration)
+            http {
+                cors {
+                    configurationSource = source
+                }
+            }
+        }
+    }
 }