mirror of
https://codeberg.org/forgejo/forgejo
synced 2024-08-22 23:51:36 +02:00
1. The "web" package shouldn't depends on "modules/context" package, instead, let each "web context" register themselves to the "web" package. 2. The old Init/Free doesn't make sense, so simplify it * The ctx in "Init(ctx)" is never used, and shouldn't be used that way * The "Free" is never called and shouldn't be called because the SSPI instance is shared --------- Co-authored-by: Giteabot <teabot@gitea.io>
184 lines
5.6 KiB
Go
184 lines
5.6 KiB
Go
// Copyright 2023 The Gitea Authors. All rights reserved.
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// SPDX-License-Identifier: MIT
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package web
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import (
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goctx "context"
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"fmt"
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"net/http"
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"reflect"
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"code.gitea.io/gitea/modules/log"
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"code.gitea.io/gitea/modules/web/routing"
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"code.gitea.io/gitea/modules/web/types"
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)
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var responseStatusProviders = map[reflect.Type]func(req *http.Request) types.ResponseStatusProvider{}
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func RegisterResponseStatusProvider[T any](fn func(req *http.Request) types.ResponseStatusProvider) {
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responseStatusProviders[reflect.TypeOf((*T)(nil)).Elem()] = fn
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}
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// responseWriter is a wrapper of http.ResponseWriter, to check whether the response has been written
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type responseWriter struct {
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respWriter http.ResponseWriter
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status int
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}
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var _ types.ResponseStatusProvider = (*responseWriter)(nil)
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func (r *responseWriter) WrittenStatus() int {
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return r.status
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}
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func (r *responseWriter) Header() http.Header {
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return r.respWriter.Header()
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}
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func (r *responseWriter) Write(bytes []byte) (int, error) {
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if r.status == 0 {
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r.status = http.StatusOK
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}
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return r.respWriter.Write(bytes)
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}
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func (r *responseWriter) WriteHeader(statusCode int) {
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r.status = statusCode
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r.respWriter.WriteHeader(statusCode)
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}
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var (
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httpReqType = reflect.TypeOf((*http.Request)(nil))
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respWriterType = reflect.TypeOf((*http.ResponseWriter)(nil)).Elem()
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cancelFuncType = reflect.TypeOf((*goctx.CancelFunc)(nil)).Elem()
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)
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// preCheckHandler checks whether the handler is valid, developers could get first-time feedback, all mistakes could be found at startup
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func preCheckHandler(fn reflect.Value, argsIn []reflect.Value) {
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hasStatusProvider := false
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for _, argIn := range argsIn {
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if _, hasStatusProvider = argIn.Interface().(types.ResponseStatusProvider); hasStatusProvider {
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break
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}
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}
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if !hasStatusProvider {
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panic(fmt.Sprintf("handler should have at least one ResponseStatusProvider argument, but got %s", fn.Type()))
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}
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if fn.Type().NumOut() != 0 && fn.Type().NumIn() != 1 {
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panic(fmt.Sprintf("handler should have no return value or only one argument, but got %s", fn.Type()))
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}
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if fn.Type().NumOut() == 1 && fn.Type().Out(0) != cancelFuncType {
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panic(fmt.Sprintf("handler should return a cancel function, but got %s", fn.Type()))
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}
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}
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func prepareHandleArgsIn(resp http.ResponseWriter, req *http.Request, fn reflect.Value, fnInfo *routing.FuncInfo) []reflect.Value {
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defer func() {
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if err := recover(); err != nil {
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log.Error("unable to prepare handler arguments for %s: %v", fnInfo.String(), err)
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panic(err)
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}
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}()
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isPreCheck := req == nil
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argsIn := make([]reflect.Value, fn.Type().NumIn())
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for i := 0; i < fn.Type().NumIn(); i++ {
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argTyp := fn.Type().In(i)
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switch argTyp {
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case respWriterType:
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argsIn[i] = reflect.ValueOf(resp)
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case httpReqType:
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argsIn[i] = reflect.ValueOf(req)
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default:
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if argFn, ok := responseStatusProviders[argTyp]; ok {
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if isPreCheck {
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argsIn[i] = reflect.ValueOf(&responseWriter{})
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} else {
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argsIn[i] = reflect.ValueOf(argFn(req))
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}
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} else {
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panic(fmt.Sprintf("unsupported argument type: %s", argTyp))
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}
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}
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}
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return argsIn
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}
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func handleResponse(fn reflect.Value, ret []reflect.Value) goctx.CancelFunc {
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if len(ret) == 1 {
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if cancelFunc, ok := ret[0].Interface().(goctx.CancelFunc); ok {
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return cancelFunc
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}
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panic(fmt.Sprintf("unsupported return type: %s", ret[0].Type()))
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} else if len(ret) > 1 {
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panic(fmt.Sprintf("unsupported return values: %s", fn.Type()))
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}
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return nil
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}
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func hasResponseBeenWritten(argsIn []reflect.Value) bool {
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for _, argIn := range argsIn {
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if statusProvider, ok := argIn.Interface().(types.ResponseStatusProvider); ok {
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if statusProvider.WrittenStatus() != 0 {
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return true
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}
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}
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}
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return false
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}
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// toHandlerProvider converts a handler to a handler provider
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// A handler provider is a function that takes a "next" http.Handler, it can be used as a middleware
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func toHandlerProvider(handler any) func(next http.Handler) http.Handler {
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funcInfo := routing.GetFuncInfo(handler)
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fn := reflect.ValueOf(handler)
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if fn.Type().Kind() != reflect.Func {
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panic(fmt.Sprintf("handler must be a function, but got %s", fn.Type()))
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}
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if hp, ok := handler.(func(next http.Handler) http.Handler); ok {
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return func(next http.Handler) http.Handler {
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h := hp(next) // this handle could be dynamically generated, so we can't use it for debug info
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return http.HandlerFunc(func(resp http.ResponseWriter, req *http.Request) {
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routing.UpdateFuncInfo(req.Context(), funcInfo)
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h.ServeHTTP(resp, req)
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})
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}
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}
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provider := func(next http.Handler) http.Handler {
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return http.HandlerFunc(func(respOrig http.ResponseWriter, req *http.Request) {
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// wrap the response writer to check whether the response has been written
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resp := respOrig
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if _, ok := resp.(types.ResponseStatusProvider); !ok {
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resp = &responseWriter{respWriter: resp}
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}
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// prepare the arguments for the handler and do pre-check
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argsIn := prepareHandleArgsIn(resp, req, fn, funcInfo)
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if req == nil {
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preCheckHandler(fn, argsIn)
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return // it's doing pre-check, just return
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}
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routing.UpdateFuncInfo(req.Context(), funcInfo)
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ret := fn.Call(argsIn)
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// handle the return value, and defer the cancel function if there is one
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cancelFunc := handleResponse(fn, ret)
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if cancelFunc != nil {
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defer cancelFunc()
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}
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// if the response has not been written, call the next handler
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if next != nil && !hasResponseBeenWritten(argsIn) {
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next.ServeHTTP(resp, req)
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}
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})
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}
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provider(nil).ServeHTTP(nil, nil) // do a pre-check to make sure all arguments and return values are supported
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return provider
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}
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