Ktor Pipeline, PipelinePhase

Pipeline을 갖는 component는 Engine, Application, Routing, Route가 있다.

각 component의 기본 phase는 다음이 있다:

Engine	EnginePipeline	before
		call
		after
	ApplicationReceivePipeline	Before
		Transform
		After
	ApplicationSendPipeline	Before
		Transform
		Render
		ContentEncoding
		TransferEncoding
		After
		Engine
Application	ApplicationCallPipeline	Setup
		Monitoring
		Plugins
		Call
		Fallback
	ApplicationReceivePipeline	Before
		Transform
		AfterTransform
		After
	ApplicationSendPipeline	Before
		Transform
		Render
		BodyTransformationCheckPostRender
		ContentEncoding
		TransferEncoding
		After
		Engine
Routing	ApplicationCallPipeline	Setup
		Monitoring
		Plugins
		Call
		Fallback
	ApplicationReceivePipeline	Before
		Transform
		After
	ApplicationSendPipeline	Before
		Transform
		Render
		ContentEncoding
		TransferEncoding
		After
		Engine
Route	ApplicationCallPipeline	Setup
		Monitoring
		Plugins
		Call
		Fallback
	ApplicationReceivePipeline	Before
		Transform
		After
	ApplicationSendPipeline	Before
		Transform
		Render
		ContentEncoding
		TransferEncoding
		After
		Engine

요청이 들어왔을 때 실행 순서는 다음과 같다:

before: Engine
Setup: Application
Monitoring: Application
Plugins: Application
Call: Application
Setup: Routing > Route
Monitoring: Routing > Route
Plugins: Routing > Route
Call: Routing > Route
// Route body 시작

Route body에서 receive를 호출하면 ApplicationReceivePipeline이 실행된다.

Before: Engine > Application > Routing > Route
Transform: Engine > (DefaultTransform) > Application > (ContentNegotiation) > Routing > Route
AfterTransform: Application
After: Engine > Application > Routing > Route
// receive 끝

respond를 호출하면 ApplicationSendPipeline이 실행된다.

Before: Engine > Application > Routing > Route
Transform: Engine > Application > Routing > Route
Render: Engine > Application > Routing > Route
BodyTransformationCheckPostRender: Application
ContentEncoding: Engine > Application > Routing > Route
TransferEncoding: Engine > Application > Routing > Route
After: Engine > Application > Routing > Route
Engine: Engine > Application > Routing > Route

- ApplicationSendPipeline은 finish를 호출하거나 respond없이 route body가 종료될 때에도 호출된다.

 

Route body가 종료되면 ApplicationCallPipeline.Fallback이 실행된다.

Fallback: Routing > Route > Application

한 요청 처리가 모두 완료될 때 EnginePipeline의 나머지 phase가 실행된다.

Engine: call > After
// 요청 끝