Support http forward

mirai-api-http/src/main/kotlin/net/mamoe/mirai/api/http/adapter/http/support/HttpForward.kt

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2023 Mamoe Technologies and contributors.
+ *
+ * 此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
+ * Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
+ *
+ * https://github.com/mamoe/mirai/blob/master/LICENSE
+ */
+
+package net.mamoe.mirai.api.http.adapter.http.support
+
+import io.ktor.http.*
+import io.ktor.server.application.*
+import io.ktor.server.request.*
+import io.ktor.util.pipeline.*
+
+suspend fun ApplicationCall.forward(forward: String) {
+    application.execute(ApplicationForwardCall(this, forward))
+}
+
+suspend fun ApplicationCall.forward(forward: String, body: Any) {
+    application.execute(ApplicationForwardCall(this, forward, body))
+}
+
+internal fun forwardReceivePipeline(body: Any): ApplicationReceivePipeline = ApplicationReceivePipeline().apply {
+    intercept(ApplicationReceivePipeline.Transform) { proceedWith(body) }
+}
+
+internal class ApplicationForwardCall(
+    val call: ApplicationCall, forward: String, body: Any? = null
+) : ApplicationCall by call {
+    override val request: ApplicationRequest = DelegateApplicationRequest(call.request, forward, body)
+}
+
+internal class DelegateApplicationRequest(
+    private val delegate: ApplicationRequest, forward: String, body: Any?
+) : ApplicationRequest by delegate {
+    private val _pipeline by lazy { body?.let { forwardReceivePipeline(it) } ?: delegate.pipeline }
+    override val local = DelegateRequestConnectionPoint(delegate.local, forward)
+    override val pipeline: ApplicationReceivePipeline = _pipeline
+}
+
+internal class DelegateRequestConnectionPoint(
+    private val delegate: RequestConnectionPoint, override val uri: String
+) : RequestConnectionPoint by delegate

mirai-api-http/src/test/kotlin/net/mamoe/mirai/api/http/adapter/http/plugin/HttpForwardTest.kt

@@ -0,0 +1,130 @@
+/*
+ * Copyright 2023 Mamoe Technologies and contributors.
+ *
+ * 此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
+ * Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
+ *
+ * https://github.com/mamoe/mirai/blob/master/LICENSE
+ */
+package net.mamoe.mirai.api.http.adapter.http.plugin
+
+import io.ktor.client.request.*
+import io.ktor.client.statement.*
+import io.ktor.http.*
+import io.ktor.serialization.kotlinx.json.*
+import io.ktor.server.application.*
+import io.ktor.server.plugins.contentnegotiation.*
+import io.ktor.server.plugins.doublereceive.*
+import io.ktor.server.request.*
+import io.ktor.server.response.*
+import io.ktor.server.routing.*
+import io.ktor.server.testing.*
+import net.mamoe.mirai.api.http.adapter.http.support.forward
+import net.mamoe.mirai.api.http.adapter.internal.dto.parameter.LongTargetDTO
+import net.mamoe.mirai.api.http.adapter.internal.dto.parameter.NudgeDTO
+import net.mamoe.mirai.api.http.adapter.internal.serializer.BuiltinJsonSerializer
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class HttpForwardTest {
+
+    @Test
+    fun testGetRequestForward() = testApplication {
+        routing {
+            get("/test") {
+                call.forward("/forward")
+            }
+
+            get("/forward") {
+                call.respondText(call.parameters["key"] ?: "null")
+            }
+        }
+
+        client.get("/test") {
+            parameter("key", "value")
+        }.also {
+            assertEquals(HttpStatusCode.OK, it.status)
+            assertEquals("value", it.bodyAsText())
+        }
+    }
+
+    @Test
+    fun testPostRequestForwardReceiveBody() = testApplication {
+        install(ContentNegotiation) { json(json=BuiltinJsonSerializer.buildJson()) }
+
+        routing {
+            post("/test") {
+                call.forward("/forward")
+            }
+
+            post("/forward") {
+                val receive = call.receive<LongTargetDTO>()
+                call.respondText(receive.target.toString())
+            }
+        }
+
+        client.post("/test") {
+            contentType(ContentType.Application.Json)
+            setBody("""{"target":123}""")
+        }.also {
+            assertEquals(HttpStatusCode.OK, it.status)
+            assertEquals("123", it.bodyAsText())
+        }
+    }
+
+    @Test
+    fun testPostRequestForwardDoubleReceiveBody() = testApplication {
+        install(DoubleReceive)
+        install(ContentNegotiation) { json(json=BuiltinJsonSerializer.buildJson()) }
+
+        routing {
+            post("/test") {
+                val receive = call.receive<LongTargetDTO>()
+                assertEquals(123, receive.target)
+                call.forward("/forward")
+            }
+
+            post("/forward") {
+                val receive = call.receive<LongTargetDTO>()
+                call.respondText(receive.target.toString())
+            }
+        }
+
+        client.post("/test") {
+            contentType(ContentType.Application.Json)
+            setBody("""{"target":123}""")
+        }.also {
+            assertEquals(HttpStatusCode.OK, it.status)
+            assertEquals("123", it.bodyAsText())
+        }
+    }
+
+    @Test
+    fun testPostRequestForwardResetBody() = testApplication {
+        // No need for DoubleReceive
+        install(DoubleReceive)
+        install(HttpRouterMonitor)
+        install(ContentNegotiation) { json(json=BuiltinJsonSerializer.buildJson()) }
+
+        routing {
+            post("/test") {
+                val receive = call.receive<LongTargetDTO>()
+                assertEquals(123, receive.target)
+                call.forward("/forward", NudgeDTO(321, 321, "kind"))
+            }
+
+            post("/forward") {
+                val receive = call.receive<NudgeDTO>()
+                call.respondText(receive.target.toString())
+            }
+        }
+
+        client.post("/test") {
+            contentType(ContentType.Application.Json)
+            setBody("""{"target":123}""")
+        }.also {
+            assertEquals(HttpStatusCode.OK, it.status)
+            assertEquals("321", it.bodyAsText())
+        }
+    }
+}