Initial 007Pay Go SDK

sign.go

@@ -0,0 +1,55 @@
+package pay007
+
+import (
+	"crypto/md5"
+	"encoding/hex"
+	"sort"
+	"strings"
+)
+
+var ignoredSignKeys = map[string]struct{}{
+	"sign":      {},
+	"sign_type": {},
+}
+
+// BuildSign creates the 007Pay merchant MD5 signature.
+//
+// Empty values, sign, and sign_type are ignored. The remaining params are
+// sorted by key, joined as "a=1&b=2", appended with the app secret, then MD5
+// hashed and upper-cased.
+func BuildSign(params map[string]string, secret string) string {
+	keys := make([]string, 0, len(params))
+	for k, v := range params {
+		if v == "" {
+			continue
+		}
+		if _, ok := ignoredSignKeys[k]; ok {
+			continue
+		}
+		keys = append(keys, k)
+	}
+	sort.Strings(keys)
+
+	var b strings.Builder
+	for i, k := range keys {
+		if i > 0 {
+			b.WriteByte('&')
+		}
+		b.WriteString(k)
+		b.WriteByte('=')
+		b.WriteString(params[k])
+	}
+	b.WriteString(secret)
+
+	sum := md5.Sum([]byte(b.String()))
+	return strings.ToUpper(hex.EncodeToString(sum[:]))
+}
+
+// VerifySign checks params["sign"] with the 007Pay signing rule.
+func VerifySign(params map[string]string, secret string) bool {
+	sign := params["sign"]
+	if sign == "" {
+		return false
+	}
+	return strings.EqualFold(BuildSign(params, secret), sign)
+}