gowechat/mch/pay/simple.go

package pay

import (
	"bytes"
	"crypto/md5"
	"encoding/hex"
	"fmt"
	"hash"
	"sort"
	"time"
	"unicode/utf8"

	"github.com/yaotian/gowechat/util"
)

//Order 下单
//https://pay.weixin.qq.com/wiki/doc/api/jsapi.php?chapter=9_1
type Order struct {
	OpenID      string //trade_type=JSAPI时（即公众号支付），此参数必传，此参数为微信用户在商户对应appid下的唯一标识
	Body        string //String(128)
	OutTradeNum string //String(32) 20150806125346 商户系统内部订单号，要求32个字符内，只能是数字、大小写字母_-|*@ ，且在同一个商户号下唯一。
	TotalFee    int    //分为单位
	IP          string
	NotifyURL   string //异步接收微信支付结果通知的回调地址，通知url必须为外网可访问的url，不能携带参数
	TradeType   string //JSAPI，NATIVE，APP
	ProductID   string //trade_type=NATIVE时（即扫码支付），此参数必传
}

//GetPrepayMap 支付页面需要的信息，map格式
func (c *Pay) GetPrepayMap(order Order) (result map[string]string, err error) {
	err = c.checkOrder(order)
	if err != nil {
		return
	}
	var prepayID string
	prepayID, err = c.getPrepayID(order)
	if err != nil {
		return
	}

	nocestr := util.RandomStr(8)
	timestamp := fmt.Sprint(time.Now().Unix())

	result = make(map[string]string)
	result["appId"] = c.AppID
	result["timeStamp"] = timestamp
	result["nonceStr"] = nocestr
	result["package"] = "prepay_id=" + prepayID
	result["signType"] = "MD5"

	sign := sign(result, c.MchAPIKey, nil)
	result["paySign"] = sign
	return
}

// 调用 UnifiedOrder 获得 prepayID
func (c *Pay) getPrepayID(order Order) (prepayID string, err error) {
	input := c.createUnifiedOrderMap(order)
	var result map[string]string
	if result, err = c.UnifiedOrder(input); err == nil { //有prepay_id
		prepayID := result["prepay_id"]
		if prepayID != "" {
			return prepayID, nil
		}
		err = fmt.Errorf("prepayID is empty")
	}
	return
}

func (c *Pay) createUnifiedOrderMap(order Order) (input map[string]string) {
	input = make(map[string]string)
	input["appid"] = c.AppID               //设置微信分配的公众账号ID
	input["mch_id"] = c.MchID              //设置微信支付分配的商户号
	input["nonce_str"] = util.RandomStr(5) //设置随机字符串，不长于32位。推荐随机数生成算法
	input["body"] = order.Body             //获取商品或支付单简要描述的值

	input["out_trade_no"] = order.OutTradeNum       //设置商户系统内部的订单号,32个字符内、可包含字母, 其他说明见商户订单号
	input["total_fee"] = util.ToStr(order.TotalFee) //设置订单总金额，只能为整数，详见支付金额
	input["spbill_create_ip"] = order.IP            //设置APP和网页支付提交用户端ip，Native支付填调用微信支付API的机器IP。
	input["notify_url"] = order.NotifyURL           //设置接收微信支付异步通知回调地址

	input["trade_type"] = order.TradeType
	//设置取值如下：JSAPI，NATIVE，APP，详细说明见参数规定

	if order.ProductID != "" {
		input["product_id"] = order.ProductID //这个
	}

	input["openid"] = order.OpenID //设置trade_type=JSAPI，此参数必传，用户在商户appid下的唯一标识。下单前需要调用【网页授权获取用户信息】接口获取到用户的Openid

	//sign
	sign := sign(input, c.MchAPIKey, nil)
	input["sign"] = sign
	return
}

// 微信支付签名.
//  parameters: 待签名的参数集合
//  apiKey:     API密钥
//  fn:         func() hash.Hash, 如果 fn == nil 则默认用 md5.New
func sign(parameters map[string]string, apiKey string, fn func() hash.Hash) string {
	ks := make([]string, 0, len(parameters))
	for k := range parameters {
		if k == "sign" {
			continue
		}
		ks = append(ks, k)
	}
	sort.Strings(ks)

	if fn == nil {
		fn = md5.New
	}
	h := fn()

	buf := make([]byte, 256)
	for _, k := range ks {
		v := parameters[k]
		if v == "" {
			continue
		}

		buf = buf[:0]
		buf = append(buf, k...)
		buf = append(buf, '=')
		buf = append(buf, v...)
		buf = append(buf, '&')
		h.Write(buf)
	}
	buf = buf[:0]
	buf = append(buf, "key="...)
	buf = append(buf, apiKey...)
	h.Write(buf)

	signature := make([]byte, h.Size()*2)
	hex.Encode(signature, h.Sum(nil))
	return string(bytes.ToUpper(signature))
}

func (c *Pay) checkOrder(order Order) (err error) {
	tradeType := order.TradeType
	if tradeType != "JSAPI" && tradeType != "APP" && tradeType != "NATIVE" {
		return fmt.Errorf("tradeType is invalid")
	}
	if tradeType == "NATIVE" {
		if order.ProductID == "" {
			err = fmt.Errorf("Native TradeType need ProductID")
			return
		}
	}
	if tradeType == "JSAPI" {
		if order.OpenID == "" {
			err = fmt.Errorf("OpenID can not be empty when pay mode is JSAPI")
			return
		}
	}
	if utf8.RuneCountInString(order.Body) > 128 || order.Body == "" {
		err = fmt.Errorf("Body is invalid. Size can not exceed 128.")
		return
	}
	if utf8.RuneCountInString(order.OutTradeNum) > 32 || order.OutTradeNum == "" {
		err = fmt.Errorf("OutTradeNum is invalid. Size can not exceed 128.")
		return
	}
	if order.TotalFee <= 0 {
		err = fmt.Errorf("Order TotalFee is invalid.")
		return
	}
	if order.IP == "" {
		err = fmt.Errorf("Order IP is invalid.")
		return
	}
	if order.NotifyURL == "" {
		err = fmt.Errorf("Notify URL is invalid.")
		return
	}

	return

}