router/router.go
2018-12-03 13:19:57 +01:00

196 lines
5.0 KiB
Go

package router
import (
"net/http"
"reflect"
"github.com/julienschmidt/httprouter"
)
type route struct {
Method string
Path string
Handle interface{}
Middleware []Middleware
}
// Handle handles a request
type Handle = func(*Context) error
// ErrorHandle handles a request
type ErrorHandle func(*Context, interface{})
// Middleware is a function that runs before your route, it gets the next handler as a parameter
type Middleware func(Handle) Handle
// Reader reads input to dst, returns true if successful
type Reader func(c *Context, dst interface{}) (bool, error)
// Router is the router itself
type Router struct {
routes []route
Reader Reader
Renderer Renderer
middleware []Middleware
NotFoundHandler Handle
MethodNotAllowedHandler Handle
ErrorHandler ErrorHandle
}
// New returns a new Router
func New() *Router {
return &Router{Reader: defaultReader, NotFoundHandler: defaultNotFoundHandler, MethodNotAllowedHandler: defaultMethodNotAllowedHandler, ErrorHandler: defaultErrorHandler}
}
// Use adds a global middleware
func (r *Router) Use(m ...Middleware) {
r.middleware = append(r.middleware, m...)
}
// Group creates a new router group with a shared prefix and set of middlewares
func (r *Router) Group(prefix string, middleware ...Middleware) *Group {
return &Group{prefix: prefix, router: r, middleware: middleware}
}
// GET adds a GET route
func (r *Router) GET(path string, handle Handle, middleware ...Middleware) {
r.routes = append(r.routes, route{`GET`, path, handle, middleware})
}
// POST adds a POST route
func (r *Router) POST(path string, handle interface{}, middleware ...Middleware) {
checkInterfaceHandle(handle)
r.routes = append(r.routes, route{`POST`, path, handle, middleware})
}
// DELETE adds a DELETE route
func (r *Router) DELETE(path string, handle Handle, middleware ...Middleware) {
r.routes = append(r.routes, route{`DELETE`, path, handle, middleware})
}
// PUT adds a PUT route
func (r *Router) PUT(path string, handle interface{}, middleware ...Middleware) {
checkInterfaceHandle(handle)
r.routes = append(r.routes, route{`PUT`, path, handle, middleware})
}
// PATCH adds a PATCH route
func (r *Router) PATCH(path string, handle interface{}, middleware ...Middleware) {
checkInterfaceHandle(handle)
r.routes = append(r.routes, route{`PATCH`, path, handle, middleware})
}
// HEAD adds a HEAD route
func (r *Router) HEAD(path string, handle Handle, middleware ...Middleware) {
r.routes = append(r.routes, route{`HEAD`, path, handle, middleware})
}
// OPTIONS adds a OPTIONS route
func (r *Router) OPTIONS(path string, handle Handle, middleware ...Middleware) {
r.routes = append(r.routes, route{`OPTIONS`, path, handle, middleware})
}
// Start starts the web server and binds to the given address
func (r *Router) Start(addr string) error {
httpr := r.getHttpr()
return http.ListenAndServe(addr, httpr)
}
func (r *Router) getHttpr() *httprouter.Router {
httpr := httprouter.New()
for _, v := range r.routes {
handle, ok := v.Handle.(Handle)
if !ok {
handle = handlePOST(r, v.Handle)
}
httpr.Handle(v.Method, v.Path, handleReq(r, handle, append(r.middleware, v.Middleware...)))
}
httpr.NotFound = http.HandlerFunc(func(res http.ResponseWriter, req *http.Request) {
handleReq(r, r.NotFoundHandler, r.middleware)(res, req, nil)
})
httpr.MethodNotAllowed = http.HandlerFunc(func(res http.ResponseWriter, req *http.Request) {
handleReq(r, r.MethodNotAllowedHandler, r.middleware)(res, req, nil)
})
httpr.PanicHandler = func(res http.ResponseWriter, req *http.Request, err interface{}) {
c := newContext(r, res, req, nil)
r.ErrorHandler(c, err)
}
return httpr
}
func checkInterfaceHandle(f interface{}) {
if _, ok := f.(Handle); ok {
return
}
rt := reflect.TypeOf(f)
if rt.Kind() != reflect.Func {
panic(`non-func handle`)
}
if rt.NumIn() != 2 {
panic(`handle should take 2 arguments`)
}
if rt.NumOut() != 1 || rt.Out(0).Name() != `error` {
panic(`handle should return only error`)
}
if rt.In(0) != reflect.TypeOf(&Context{}) {
panic(`handle should accept Context as first argument`)
}
return
}
func handlePOST(r *Router, f interface{}) Handle {
funcRv, inputRt := reflect.ValueOf(f), reflect.TypeOf(f).In(1)
return func(c *Context) error {
data := reflect.New(inputRt)
if r.Reader != nil {
ok, err := r.Reader(c, data.Interface())
_ = c.Request.Body.Close()
if err != nil {
return err
}
if !ok {
return nil
}
}
out := funcRv.Call([]reflect.Value{reflect.ValueOf(c), data.Elem()})
if out[0].IsNil() {
return nil
}
return out[0].Interface().(error)
}
}
func handleReq(r *Router, handle Handle, m []Middleware) httprouter.Handle {
return func(res http.ResponseWriter, req *http.Request, param httprouter.Params) {
c := newContext(r, res, req, param)
f := handle
for i := len(m) - 1; i >= 0; i-- { // TODO: 1,2,3 of 3,2,1
f = m[i](f)
}
err := f(c)
if err != nil {
r.ErrorHandler(c, err)
}
}
}