gitea/modules/web/route.go
wxiaoguang b9a97ccd0e
Refactor web route (#24080)
The old code is unnecessarily complex, and has many misuses.

Old code "wraps" a lot, wrap wrap wrap, it's difficult to understand
which kind of handler is used.

The new code uses a general approach, we do not need to write all kinds
of handlers into the "wrapper", do not need to wrap them again and
again.

New code, there are only 2 concepts:

1. HandlerProvider: `func (h any) (handlerProvider func (next)
http.Handler)`, it can be used as middleware
2. Use HandlerProvider to get the final HandlerFunc, and use it for
`r.Get()`


And we can decouple the route package from context package (see the
TODO).

# FAQ

## Is `reflect` safe?

Yes, all handlers are checked during startup, see the `preCheckHandler`
comment. If any handler is wrong, developers could know it in the first
time.

## Does `reflect` affect performance?

No. https://github.com/go-gitea/gitea/pull/24080#discussion_r1164825901

1. This reflect code only runs for each web handler call, handler is far
more slower: 10ms-50ms
2. The reflect is pretty fast (comparing to other code): 0.000265ms
3. XORM has more reflect operations already
2023-04-20 14:49:06 -04:00

227 lines
6.1 KiB
Go

// Copyright 2020 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package web
import (
"net/http"
"strings"
"code.gitea.io/gitea/modules/context"
"code.gitea.io/gitea/modules/web/middleware"
"gitea.com/go-chi/binding"
chi "github.com/go-chi/chi/v5"
)
// Bind binding an obj to a handler
func Bind[T any](_ T) any {
return func(ctx *context.Context) {
theObj := new(T) // create a new form obj for every request but not use obj directly
binding.Bind(ctx.Req, theObj)
SetForm(ctx, theObj)
middleware.AssignForm(theObj, ctx.Data)
}
}
// SetForm set the form object
func SetForm(data middleware.DataStore, obj interface{}) {
data.GetData()["__form"] = obj
}
// GetForm returns the validate form information
func GetForm(data middleware.DataStore) interface{} {
return data.GetData()["__form"]
}
// Route defines a route based on chi's router
type Route struct {
R chi.Router
curGroupPrefix string
curMiddlewares []interface{}
}
// NewRoute creates a new route
func NewRoute() *Route {
r := chi.NewRouter()
return &Route{
R: r,
curGroupPrefix: "",
curMiddlewares: []interface{}{},
}
}
// Use supports two middlewares
func (r *Route) Use(middlewares ...interface{}) {
if r.curGroupPrefix != "" {
// FIXME: this behavior is incorrect, should use "With" instead
r.curMiddlewares = append(r.curMiddlewares, middlewares...)
} else {
// FIXME: another misuse, the "Use" with empty middlewares is called after "Mount"
for _, m := range middlewares {
r.R.Use(toHandlerProvider(m))
}
}
}
// Group mounts a sub-Router along a `pattern` string.
func (r *Route) Group(pattern string, fn func(), middlewares ...interface{}) {
previousGroupPrefix := r.curGroupPrefix
previousMiddlewares := r.curMiddlewares
r.curGroupPrefix += pattern
r.curMiddlewares = append(r.curMiddlewares, middlewares...)
fn()
r.curGroupPrefix = previousGroupPrefix
r.curMiddlewares = previousMiddlewares
}
func (r *Route) getPattern(pattern string) string {
newPattern := r.curGroupPrefix + pattern
if !strings.HasPrefix(newPattern, "/") {
newPattern = "/" + newPattern
}
if newPattern == "/" {
return newPattern
}
return strings.TrimSuffix(newPattern, "/")
}
func (r *Route) wrapMiddlewareAndHandler(h []any) ([]func(http.Handler) http.Handler, http.HandlerFunc) {
handlerProviders := make([]func(http.Handler) http.Handler, 0, len(r.curMiddlewares)+len(h))
for _, m := range r.curMiddlewares {
handlerProviders = append(handlerProviders, toHandlerProvider(m))
}
for _, m := range h {
handlerProviders = append(handlerProviders, toHandlerProvider(m))
}
middlewares := handlerProviders[:len(handlerProviders)-1]
handlerFunc := handlerProviders[len(handlerProviders)-1](nil).ServeHTTP
return middlewares, handlerFunc
}
func (r *Route) Methods(method, pattern string, h []any) {
middlewares, handlerFunc := r.wrapMiddlewareAndHandler(h)
fullPattern := r.getPattern(pattern)
if strings.Contains(method, ",") {
methods := strings.Split(method, ",")
for _, method := range methods {
r.R.With(middlewares...).Method(strings.TrimSpace(method), fullPattern, handlerFunc)
}
} else {
r.R.With(middlewares...).Method(method, fullPattern, handlerFunc)
}
}
// Mount attaches another Route along ./pattern/*
func (r *Route) Mount(pattern string, subR *Route) {
middlewares := make([]interface{}, len(r.curMiddlewares))
copy(middlewares, r.curMiddlewares)
subR.Use(middlewares...)
r.R.Mount(r.getPattern(pattern), subR.R)
}
// Any delegate requests for all methods
func (r *Route) Any(pattern string, h ...interface{}) {
middlewares, handlerFunc := r.wrapMiddlewareAndHandler(h)
r.R.With(middlewares...).HandleFunc(r.getPattern(pattern), handlerFunc)
}
// RouteMethods delegate special methods, it is an alias of "Methods", while the "pattern" is the first parameter
func (r *Route) RouteMethods(pattern, methods string, h ...interface{}) {
r.Methods(methods, pattern, h)
}
// Delete delegate delete method
func (r *Route) Delete(pattern string, h ...interface{}) {
r.Methods("DELETE", pattern, h)
}
// Get delegate get method
func (r *Route) Get(pattern string, h ...interface{}) {
r.Methods("GET", pattern, h)
}
// GetOptions delegate get and options method
func (r *Route) GetOptions(pattern string, h ...interface{}) {
r.Methods("GET,OPTIONS", pattern, h)
}
// PostOptions delegate post and options method
func (r *Route) PostOptions(pattern string, h ...interface{}) {
r.Methods("POST,OPTIONS", pattern, h)
}
// Head delegate head method
func (r *Route) Head(pattern string, h ...interface{}) {
r.Methods("HEAD", pattern, h)
}
// Post delegate post method
func (r *Route) Post(pattern string, h ...interface{}) {
r.Methods("POST", pattern, h)
}
// Put delegate put method
func (r *Route) Put(pattern string, h ...interface{}) {
r.Methods("PUT", pattern, h)
}
// Patch delegate patch method
func (r *Route) Patch(pattern string, h ...interface{}) {
r.Methods("PATCH", pattern, h)
}
// ServeHTTP implements http.Handler
func (r *Route) ServeHTTP(w http.ResponseWriter, req *http.Request) {
r.R.ServeHTTP(w, req)
}
// NotFound defines a handler to respond whenever a route could not be found.
func (r *Route) NotFound(h http.HandlerFunc) {
r.R.NotFound(h)
}
// Combo delegates requests to Combo
func (r *Route) Combo(pattern string, h ...interface{}) *Combo {
return &Combo{r, pattern, h}
}
// Combo represents a tiny group routes with same pattern
type Combo struct {
r *Route
pattern string
h []interface{}
}
// Get delegates Get method
func (c *Combo) Get(h ...interface{}) *Combo {
c.r.Get(c.pattern, append(c.h, h...)...)
return c
}
// Post delegates Post method
func (c *Combo) Post(h ...interface{}) *Combo {
c.r.Post(c.pattern, append(c.h, h...)...)
return c
}
// Delete delegates Delete method
func (c *Combo) Delete(h ...interface{}) *Combo {
c.r.Delete(c.pattern, append(c.h, h...)...)
return c
}
// Put delegates Put method
func (c *Combo) Put(h ...interface{}) *Combo {
c.r.Put(c.pattern, append(c.h, h...)...)
return c
}
// Patch delegates Patch method
func (c *Combo) Patch(h ...interface{}) *Combo {
c.r.Patch(c.pattern, append(c.h, h...)...)
return c
}