Move ServerWebExchange Kotlin extensions

This commit moves ServerWebExchange Kotlin extensions
where they belong: in the spring-web module with the
org.springframework.web.server package, like
ServerWebExchange itself.

The extensions in the wrong location are deprecated
and semi-automated migration to the new variants is
made possible via @Deprecated + ReplaceWith(...).

Some tests have been added as well.

Closes gh-31046

spring-web/src/main/kotlin/org/springframework/web/server/ServerWebExchangeExtensions.kt

@@ -0,0 +1,69 @@
+/*
+ * Copyright 2002-2023 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://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 org.springframework.web.server
+
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.reactive.awaitSingle
+import kotlinx.coroutines.reactor.mono
+import org.springframework.http.codec.multipart.Part
+import org.springframework.util.MultiValueMap
+import java.security.Principal
+
+/**
+ * Coroutines variant of [ServerWebExchange.getFormData].
+ *
+ * @author Sebastien Deleuze
+ * @since 6.1
+ */
+suspend fun ServerWebExchange.awaitFormData(): MultiValueMap<String, String> =
+		this.formData.awaitSingle()
+
+/**
+ * Coroutines variant of [ServerWebExchange.getMultipartData].
+ *
+ * @author Sebastien Deleuze
+ * @since 6.1
+ */
+suspend fun ServerWebExchange.awaitMultipartData(): MultiValueMap<String, Part> =
+		this.multipartData.awaitSingle()
+
+/**
+ * Coroutines variant of [ServerWebExchange.getPrincipal].
+ *
+ * @author Sebastien Deleuze
+ * @since 6.1
+ */
+suspend fun <T : Principal> ServerWebExchange.awaitPrincipal(): T =
+		this.getPrincipal<T>().awaitSingle()
+
+/**
+ * Coroutines variant of [ServerWebExchange.getSession].
+ *
+ * @author Sebastien Deleuze
+ * @since 6.1
+ */
+suspend fun ServerWebExchange.awaitSession(): WebSession =
+		this.session.awaitSingle()
+
+/**
+ * Coroutines variant of [ServerWebExchange.Builder.principal].
+ *
+ * @author Sebastien Deleuze
+ * @since 6.1
+ */
+fun ServerWebExchange.Builder.principal(supplier: suspend () -> Principal): ServerWebExchange.Builder
+        = principal(mono(Dispatchers.Unconfined) { supplier.invoke() })

spring-web/src/test/kotlin/org/springframework/web/server/ServerWebExchangeExtensionsTest.kt

@@ -0,0 +1,89 @@
+/*
+ * Copyright 2002-2023 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://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 org.springframework.web.server
+
+import io.mockk.every
+import io.mockk.mockk
+import io.mockk.verify
+import kotlinx.coroutines.runBlocking
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Test
+import org.springframework.http.codec.multipart.Part
+import org.springframework.util.MultiValueMap
+import reactor.core.publisher.Mono
+import java.security.Principal
+
+/**
+ * Mock object based tests for [ServerWebExchange] Kotlin extensions
+ *
+ * @author Sebastien Deleuze
+ */
+class ServerWebExchangeExtensionsTest {
+
+	@Test
+	fun `awaitFormData extension`() {
+		val exchange = mockk<ServerWebExchange>()
+		val multiMap = mockk<MultiValueMap<String, String>>()
+		every { exchange.formData } returns Mono.just(multiMap)
+		runBlocking {
+			assertThat(exchange.awaitFormData()).isEqualTo(multiMap)
+		}
+	}
+
+	@Test
+	fun `awaitMultipartData extension`() {
+		val exchange = mockk<ServerWebExchange>()
+		val multiMap = mockk<MultiValueMap<String, Part>>()
+		every { exchange.multipartData } returns Mono.just(multiMap)
+		runBlocking {
+			assertThat(exchange.awaitMultipartData()).isEqualTo(multiMap)
+		}
+	}
+
+	@Test
+	fun `awaitPrincipal extension`() {
+		val exchange = mockk<ServerWebExchange>()
+		val principal = mockk<Principal>()
+		every { exchange.getPrincipal<Principal>() } returns Mono.just(principal)
+		runBlocking {
+			assertThat(exchange.awaitPrincipal<Principal>()).isEqualTo(principal)
+		}
+		verify { exchange.getPrincipal<Principal>() }
+	}
+
+	@Test
+	fun `awaitSession extension`() {
+		val exchange = mockk<ServerWebExchange>()
+		val session = mockk<WebSession>()
+		every { exchange.session } returns Mono.just(session)
+		runBlocking {
+			assertThat(exchange.awaitSession()).isEqualTo(session)
+		}
+	}
+
+	@Test
+	fun `principal builder extension`() {
+		val builder = mockk<ServerWebExchange.Builder>()
+		val principal = mockk<Principal>()
+		every { builder.principal(any<Mono<Principal>>()) } returns builder
+		runBlocking {
+			assertThat(builder.principal { principal }).isEqualTo(builder)
+		}
+		verify { builder.principal(any<Mono<Principal>>()) }
+	}
+
+}

spring-webflux/src/main/kotlin/org/springframework/web/reactive/server/ServerWebExchangeExtensions.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -31,6 +31,10 @@ import java.security.Principal
  * @author Sebastien Deleuze
  * @since 5.2
  */
+@Deprecated(
+	message = "Use the variant with the org.springframework.web.server package instead.",
+	ReplaceWith("awaitFormData()", "org.springframework.web.server.awaitFormData"),
+)
 suspend fun ServerWebExchange.awaitFormData(): MultiValueMap<String, String> =
 		this.formData.awaitSingle()
 
@@ -40,6 +44,10 @@ suspend fun ServerWebExchange.awaitFormData(): MultiValueMap<String, String> =
  * @author Sebastien Deleuze
  * @since 5.2
  */
+@Deprecated(
+	message = "Use the variant with the org.springframework.web.server package instead.",
+	ReplaceWith("awaitMultipartData()", "org.springframework.web.server.awaitMultipartData"),
+)
 suspend fun ServerWebExchange.awaitMultipartData(): MultiValueMap<String, Part> =
 		this.multipartData.awaitSingle()
 
@@ -49,6 +57,10 @@ suspend fun ServerWebExchange.awaitMultipartData(): MultiValueMap<String, Part>
  * @author Sebastien Deleuze
  * @since 5.2
  */
+@Deprecated(
+	message = "Use the variant with the org.springframework.web.server package instead.",
+	ReplaceWith("awaitPrincipal<T>()", "org.springframework.web.server.awaitPrincipal"),
+)
 suspend fun <T : Principal> ServerWebExchange.awaitPrincipal(): T =
 		this.getPrincipal<T>().awaitSingle()
 
@@ -58,6 +70,10 @@ suspend fun <T : Principal> ServerWebExchange.awaitPrincipal(): T =
  * @author Sebastien Deleuze
  * @since 5.2
  */
+@Deprecated(
+	message = "Use the variant with the org.springframework.web.server package instead.",
+	ReplaceWith("awaitSession()", "org.springframework.web.server.awaitSession"),
+)
 suspend fun ServerWebExchange.awaitSession(): WebSession =
 		this.session.awaitSingle()
 
@@ -67,5 +83,9 @@ suspend fun ServerWebExchange.awaitSession(): WebSession =
  * @author Sebastien Deleuze
  * @since 5.2
  */
+@Deprecated(
+	message = "Use the variant with the org.springframework.web.server package instead.",
+	ReplaceWith("principal(supplier)", "org.springframework.web.server.principal"),
+)
 fun ServerWebExchange.Builder.principal(supplier: suspend () -> Principal): ServerWebExchange.Builder
         = principal(mono(Dispatchers.Unconfined) { supplier.invoke() })