fix some bugs (#277)

* fix payRequset xml marshal: root element should be xml

* support HMAC-SHA256 for unifiedorder api

* support HMAC-SHA256 for PaidVerifySign

* fix SignType is nil

* fix code style

* constantize SignType

* add comments

* fix code style

util/param.go

@@ -3,65 +3,31 @@ package util
 import (
 	"bytes"
 	"sort"
-	"strconv"
 )
 
 // OrderParam order params
-func OrderParam(source interface{}, bizKey string) (returnStr string) {
-	switch v := source.(type) {
-	case map[string]string:
-		keys := make([]string, 0, len(v))
-		for k := range v {
-			if k == "sign" {
-				continue
-			}
-			keys = append(keys, k)
+func OrderParam(p map[string]string, bizKey string) (returnStr string) {
+	keys := make([]string, 0, len(p))
+	for k := range p {
+		if k == "sign" {
+			continue
 		}
-		sort.Strings(keys)
-		var buf bytes.Buffer
-		for _, k := range keys {
-			if v[k] == "" {
-				continue
-			}
-			if buf.Len() > 0 {
-				buf.WriteByte('&')
-			}
-			buf.WriteString(k)
-			buf.WriteByte('=')
-			buf.WriteString(v[k])
-		}
-		buf.WriteString(bizKey)
-		returnStr = buf.String()
-	case map[string]interface{}:
-		keys := make([]string, 0, len(v))
-		for k := range v {
-			if k == "sign" {
-				continue
-			}
-			keys = append(keys, k)
-		}
-		sort.Strings(keys)
-		var buf bytes.Buffer
-		for _, k := range keys {
-			if v[k] == "" {
-				continue
-			}
-			if buf.Len() > 0 {
-				buf.WriteByte('&')
-			}
-			buf.WriteString(k)
-			buf.WriteByte('=')
-			switch vv := v[k].(type) {
-			case string:
-				buf.WriteString(vv)
-			case int:
-				buf.WriteString(strconv.FormatInt(int64(vv), 10))
-			default:
-				panic("params type not supported")
-			}
-		}
-		buf.WriteString(bizKey)
-		returnStr = buf.String()
+		keys = append(keys, k)
 	}
+	sort.Strings(keys)
+	var buf bytes.Buffer
+	for _, k := range keys {
+		if p[k] == "" {
+			continue
+		}
+		if buf.Len() > 0 {
+			buf.WriteByte('&')
+		}
+		buf.WriteString(k)
+		buf.WriteByte('=')
+		buf.WriteString(p[k])
+	}
+	buf.WriteString(bizKey)
+	returnStr = buf.String()
 	return
 }