apigen/test/demo/api/apigen.go

package api

import (
	"context"
	"encoding/json"
	"errors"
	"net/http"
	"reflect"
	"strconv"
	"strings"
)

func handleTag(s string, r *http.Request) string {
	parts := strings.Split(s, ":")
	where := "Q"
	key := ""
	if len(parts) == 1 {
		key = parts[0]
	} else {
		where = parts[0]
		key = parts[1]
	}

	switch where {
	case "Q":
		return r.URL.Query().Get(key)
	case "H":
		return r.Header.Get(key)
	case "P":
		switch key {
		case "*":
			return r.URL.Path
		case "last":
			pps := strings.Split(r.URL.Path, "/")
			return pps[len(pps)-1]
		case "len":
			pps := strings.Split(r.URL.Path, "/")
			return strconv.Itoa(len(pps))
		default:
			pps := strings.Split(r.URL.Path, "/")
			n, _ := strconv.Atoi(key)
			if n < len(pps) {
				return pps[n]
			}
			return ""
		}
	}
	return ""
}

func convert(s string, tpname string) interface{} {
	switch tpname {
	case "string":
		return s

	case "int":
		v, _ := strconv.Atoi(s)
		return v
	case "int8":
		v, _ := strconv.Atoi(s)
		return int8(v)
	case "int16":
		v, _ := strconv.Atoi(s)
		return int16(v)
	case "int32":
		v, _ := strconv.Atoi(s)
		return int32(v)
	case "int64":
		v, _ := strconv.Atoi(s)
		return int64(v)
	case "uint":
		v, _ := strconv.Atoi(s)
		return uint(v)
	case "float32":
		v, _ := strconv.Atoi(s)
		return float32(v)
	case "float64":
		v, _ := strconv.Atoi(s)
		return float64(v)
	case "bool":
		return s == "true" || s == "1" || s == "Y"
	}
	return nil
}

func Map(r *http.Request, in interface{}) error {

	tp := reflect.TypeOf(in)
	vl := reflect.ValueOf(in)
	if tp.Kind() == reflect.Ptr {
		tp = tp.Elem()
		vl = vl.Elem()
	}
	if tp.Kind() != reflect.Struct {
		return errors.New("Type is not struct")
	}

	for i := 0; i < tp.NumField(); i++ {
		k, ok := tp.Field(i).Tag.Lookup("in")
		if ok {
			str := handleTag(k, r)
			v := convert(str, tp.Field(i).Type.Name())
			strv := reflect.ValueOf(v)
			vl.Field(i).Set(strv)
		}
	}
	return nil
}

type API struct {
	Mux   *http.ServeMux
	Perms map[string]string
}

func (a *API) GetPerm(r *http.Request) string {
	return a.Perms[r.Method+"_"+strings.Split(r.RequestURI, "?")[0]]
}

func h_Dosome(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()
	ctx = context.WithValue(r.Context(), "REQ", r)
	ctx = context.WithValue(ctx, "RES", w)
	req := &SomeReq{}
	err := Map(r, req)
	if err != nil {
		http.Error(w, err.Error(), 500)
		return
	}
	if r.Method != http.MethodGet && r.Method != http.MethodHead {
		err := json.NewDecoder(r.Body).Decode(req)
		if err != nil {
			http.Error(w, err.Error(), 500)
			return
		}
	}
	res, err := Dosome(ctx, req)
	if err != nil {
		http.Error(w, err.Error(), 500)
		return
	}
	w.Header().Add("Content-Type", "Application/json")
	err = json.NewEncoder(w).Encode(res)
	if err != nil {
		http.Error(w, err.Error(), 500)
		return
	}
}
func h_Dosome2(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()
	ctx = context.WithValue(r.Context(), "REQ", r)
	ctx = context.WithValue(ctx, "RES", w)
	req := &SomeReq2{}
	err := Map(r, req)
	if err != nil {
		http.Error(w, err.Error(), 500)
		return
	}
	if r.Method != http.MethodGet && r.Method != http.MethodHead {
		err := json.NewDecoder(r.Body).Decode(req)
		if err != nil {
			http.Error(w, err.Error(), 500)
			return
		}
	}
	res, err := Dosome2(ctx, req)
	if err != nil {
		http.Error(w, err.Error(), 500)
		return
	}
	w.Header().Add("Content-Type", "Application/json")
	err = json.NewEncoder(w).Encode(res)
	if err != nil {
		http.Error(w, err.Error(), 500)
		return
	}
}
func Init() *API {
	mux := &http.ServeMux{}

	ret := &API{
		Mux:   mux,
		Perms: make(map[string]string),
	}
	mux.HandleFunc("/some", func(w http.ResponseWriter, r *http.Request) {
		switch r.Method {
		case "POST":
			h_Dosome(w, r)
		default:
			http.Error(w, "Method not allowed", 500)
		}
	})
	mux.HandleFunc("/some2", func(w http.ResponseWriter, r *http.Request) {
		switch r.Method {
		case "POST":
			h_Dosome2(w, r)
		default:
			http.Error(w, "Method not allowed", 500)
		}
	})
	return ret
}