Go语言实现APPID登录

package thirdparty

import (
	"crypto/rsa"
	"fmt"
	"github.com/dgrijalva/jwt-go"
	"github.com/lestrrat-go/jwx/jwk"
	"github.com/pkg/errors"
	"github.com/wonderivan/logger"
	"math/big"
	"net/http"
)

func bigFromByte(s []uint8) *big.Int {
	ret := new(big.Int)
	ret.SetBytes(s)
	return ret
}

// 解析token
func AppleParseToken(appleToken string) (string, error) {
	set, err := jwk.FetchHTTP("https://appleid.apple.com/auth/keys",
		jwk.WithHTTPClient(http.DefaultClient))
	if err != nil {
		return "", err
	}
	var isSuccess bool
	var token *jwt.Token //要对每一个公钥都去进行解析，有一个成功了就行，全失败才算失败
	for _, key := range set.Keys {
		fmt.Println(key)
		NIface, _ := key.Get("n")
		NStr := NIface.([]uint8)
		EIface, _ := key.Get("e")
		EStr := EIface.([]uint8)
		pubKey := &rsa.PublicKey{N: bigFromByte(NStr), E: int(bigFromByte(EStr).Int64())}
		token, err = jwt.Parse(appleToken, func(token *jwt.Token) (interface{}, error) {
			if _, ok := token.Method.(*jwt.SigningMethodRSA); !ok {
				logger.Error("Unexpected signing method: %v", token.Header["alg"])
			}
			return pubKey, nil
		})
		if err != nil {
			logger.Error("Token Parse error:", err)
			continue
		}
		if !token.Valid {
			logger.Error("Token is invalid")
			continue
		}
		isSuccess = true
		break
	}
	if isSuccess == false {
		return "", errors.New("Token is invalid")
	}
	claims := token.Claims.(jwt.MapClaims)
	sub, ok := claims["sub"].(string)
	if !ok || sub == "" {
		return "", errors.New("Token abnormal")
	}
	logger.Info("Token verification success")
	return sub, nil
}