// ServeHTTP 处理 http 消息请求
// NOTE: 调用者保证所有参数有效
func ServeHTTP(w http.ResponseWriter, r *http.Request, queryValues url.Values, srv Server, errHandler mp.ErrorHandler) {
switch r.Method {
case "POST": // 消息处理
switch encryptType := queryValues.Get("encrypt_type"); encryptType {
case "aes":
msgSignature1 := queryValues.Get("msg_signature")
if msgSignature1 == "" {
errHandler.ServeError(w, r, errors.New("msg_signature is empty"))
return
}
timestampStr := queryValues.Get("timestamp")
if timestampStr == "" {
errHandler.ServeError(w, r, errors.New("timestamp is empty"))
return
}
timestamp, err := strconv.ParseInt(timestampStr, 10, 64)
if err != nil {
err = errors.New("can not parse timestamp to int64: " + timestampStr)
errHandler.ServeError(w, r, err)
return
}
nonce := queryValues.Get("nonce")
if nonce == "" {
errHandler.ServeError(w, r, errors.New("nonce is empty"))
return
}
var requestHttpBody RequestHttpBody
if err := xml.NewDecoder(r.Body).Decode(&requestHttpBody); err != nil {
errHandler.ServeError(w, r, err)
return
}
haveAppId := requestHttpBody.AppId
wantAppId := srv.AppId()
if wantAppId != "" && !security.SecureCompareString(haveAppId, wantAppId) {
err = fmt.Errorf("the RequestHttpBody's AppId mismatch, have: %s, want: %s", haveAppId, wantAppId)
errHandler.ServeError(w, r, err)
return
}
token := srv.Token()
// 验证签名
msgSignature2 := util.MsgSign(token, timestampStr, nonce, requestHttpBody.EncryptedMsg)
if !security.SecureCompareString(msgSignature1, msgSignature2) {
err = fmt.Errorf("check msg_signature failed, input: %s, local: %s", msgSignature1, msgSignature2)
errHandler.ServeError(w, r, err)
return
}
// 解密
encryptedMsgBytes, err := base64.StdEncoding.DecodeString(requestHttpBody.EncryptedMsg)
if err != nil {
errHandler.ServeError(w, r, err)
return
}
aesKey := srv.CurrentAESKey()
random, rawMsgXML, aesAppId, err := util.AESDecryptMsg(encryptedMsgBytes, aesKey)
if err != nil {
// 尝试用上一次的 AESKey 来解密
lastAESKey, isLastAESKeyValid := srv.LastAESKey()
if !isLastAESKeyValid {
errHandler.ServeError(w, r, err)
return
}
aesKey = lastAESKey // NOTE
random, rawMsgXML, aesAppId, err = util.AESDecryptMsg(encryptedMsgBytes, aesKey)
if err != nil {
errHandler.ServeError(w, r, err)
return
}
}
if haveAppId != string(aesAppId) {
err = fmt.Errorf("the RequestHttpBody's ToUserName(==%s) mismatch the AppId with aes encrypt(==%s)", haveAppId, aesAppId)
errHandler.ServeError(w, r, err)
return
}
// 解密成功, 解析 MixedMessage
var mixedMsg MixedMessage
if err := xml.Unmarshal(rawMsgXML, &mixedMsg); err != nil {
errHandler.ServeError(w, r, err)
return
}
// 安全考虑再次验证 AppId
if haveAppId != mixedMsg.AppId {
err = fmt.Errorf("the RequestHttpBody's AppId(==%s) mismatch the MixedMessage's AppId(==%s)", haveAppId, mixedMsg.AppId)
errHandler.ServeError(w, r, err)
return
}
// 成功, 交给 MessageHandler
req := &Request{
Token: token,
HttpRequest: r,
QueryValues: queryValues,
MsgSignature: msgSignature1,
EncryptType: encryptType,
Timestamp: timestamp,
Nonce: nonce,
RawMsgXML: rawMsgXML,
MixedMsg: &mixedMsg,
AESKey: aesKey,
Random: random,
AppId: haveAppId,
}
srv.MessageHandler().ServeMessage(w, req)
default: // 未知的加密类型
err := errors.New("unknown encrypt_type: " + encryptType)
errHandler.ServeError(w, r, err)
return
}
case "GET": // 首次验证
signature1 := queryValues.Get("signature")
if signature1 == "" {
errHandler.ServeError(w, r, errors.New("signature is empty"))
return
}
timestamp := queryValues.Get("timestamp")
if timestamp == "" {
errHandler.ServeError(w, r, errors.New("timestamp is empty"))
return
}
nonce := queryValues.Get("nonce")
if nonce == "" {
errHandler.ServeError(w, r, errors.New("nonce is empty"))
return
}
echostr := queryValues.Get("echostr")
if echostr == "" {
errHandler.ServeError(w, r, errors.New("echostr is empty"))
return
}
signature2 := util.Sign(srv.Token(), timestamp, nonce)
if !security.SecureCompareString(signature1, signature2) {
err := fmt.Errorf("check signature failed, input: %s, local: %s", signature1, signature2)
errHandler.ServeError(w, r, err)
return
}
io.WriteString(w, echostr)
}
}
// ServeHTTP 处理 http 消息请求
// NOTE: 调用者保证所有参数有效
func ServeHTTP(w http.ResponseWriter, r *http.Request, queryValues url.Values, srv Server, errHandler ErrorHandler) {
LogInfoln("[WECHAT_DEBUG] request uri:", r.RequestURI)
LogInfoln("[WECHAT_DEBUG] request remote-addr:", r.RemoteAddr)
LogInfoln("[WECHAT_DEBUG] request user-agent:", r.UserAgent())
switch r.Method {
case "POST": // 消息处理
switch encryptType := queryValues.Get("encrypt_type"); encryptType {
case "aes": // 安全模式, 兼容模式
signature := queryValues.Get("signature") // 只读取, 不做校验
msgSignature1 := queryValues.Get("msg_signature")
if msgSignature1 == "" {
errHandler.ServeError(w, r, errors.New("msg_signature is empty"))
return
}
timestampStr := queryValues.Get("timestamp")
if timestampStr == "" {
errHandler.ServeError(w, r, errors.New("timestamp is empty"))
return
}
timestamp, err := strconv.ParseInt(timestampStr, 10, 64)
if err != nil {
err = errors.New("can not parse timestamp to int64: " + timestampStr)
errHandler.ServeError(w, r, err)
return
}
nonce := queryValues.Get("nonce")
if nonce == "" {
errHandler.ServeError(w, r, errors.New("nonce is empty"))
return
}
reqBody, err := ioutil.ReadAll(r.Body)
if err != nil {
errHandler.ServeError(w, r, err)
return
}
LogInfoln("[WECHAT_DEBUG] request msg http body:\r\n", string(reqBody))
var requestHttpBody RequestHttpBody
if err := xml.Unmarshal(reqBody, &requestHttpBody); err != nil {
errHandler.ServeError(w, r, err)
return
}
// 安全考虑验证下 ToUserName
haveToUserName := requestHttpBody.ToUserName
wantToUserName := srv.OriId()
if wantToUserName != "" && !security.SecureCompareString(haveToUserName, wantToUserName) {
err := fmt.Errorf("the RequestHttpBody's ToUserName mismatch, have: %s, want: %s", haveToUserName, wantToUserName)
errHandler.ServeError(w, r, err)
return
}
token := srv.Token()
// 验证签名
msgSignature2 := util.MsgSign(token, timestampStr, nonce, requestHttpBody.EncryptedMsg)
if !security.SecureCompareString(msgSignature1, msgSignature2) {
err := fmt.Errorf("check msg_signature failed, input: %s, local: %s", msgSignature1, msgSignature2)
errHandler.ServeError(w, r, err)
return
}
// 解密
encryptedMsgBytes, err := base64.StdEncoding.DecodeString(requestHttpBody.EncryptedMsg)
if err != nil {
errHandler.ServeError(w, r, err)
return
}
aesKey := srv.CurrentAESKey()
random, rawMsgXML, haveAppIdBytes, err := util.AESDecryptMsg(encryptedMsgBytes, aesKey)
if err != nil {
// 尝试用上一次的 AESKey 来解密
lastAESKey, isLastAESKeyValid := srv.LastAESKey()
if !isLastAESKeyValid {
errHandler.ServeError(w, r, err)
return
}
aesKey = lastAESKey // NOTE
random, rawMsgXML, haveAppIdBytes, err = util.AESDecryptMsg(encryptedMsgBytes, aesKey)
if err != nil {
errHandler.ServeError(w, r, err)
return
}
}
haveAppId := string(haveAppIdBytes)
wantAppId := srv.AppId()
if wantAppId != "" && !security.SecureCompareString(haveAppId, wantAppId) {
err := fmt.Errorf("the message's appid mismatch, have: %s, want: %s", haveAppId, wantAppId)
errHandler.ServeError(w, r, err)
return
}
LogInfoln("[WECHAT_DEBUG] request msg raw xml:\r\n", string(rawMsgXML))
// 解密成功, 解析 MixedMessage
var mixedMsg MixedMessage
if err := xml.Unmarshal(rawMsgXML, &mixedMsg); err != nil {
errHandler.ServeError(w, r, err)
return
}
// 安全考虑再次验证 ToUserName
if haveToUserName != mixedMsg.ToUserName {
err := fmt.Errorf("the RequestHttpBody's ToUserName(==%s) mismatch the MixedMessage's ToUserName(==%s)", haveToUserName, mixedMsg.ToUserName)
errHandler.ServeError(w, r, err)
return
}
// 成功, 交给 MessageHandler
req := &Request{
Token: token,
HttpRequest: r,
QueryValues: queryValues,
Signature: signature,
Timestamp: timestamp,
Nonce: nonce,
EncryptType: encryptType,
RawMsgXML: rawMsgXML,
MixedMsg: &mixedMsg,
MsgSignature: msgSignature1,
AESKey: aesKey,
Random: random,
AppId: haveAppId,
}
srv.MessageHandler().ServeMessage(w, req)
case "", "raw": // 明文模式
signature1 := queryValues.Get("signature")
if signature1 == "" {
errHandler.ServeError(w, r, errors.New("signature is empty"))
return
}
timestampStr := queryValues.Get("timestamp")
if timestampStr == "" {
errHandler.ServeError(w, r, errors.New("timestamp is empty"))
return
}
timestamp, err := strconv.ParseInt(timestampStr, 10, 64)
if err != nil {
err = errors.New("can not parse timestamp to int64: " + timestampStr)
errHandler.ServeError(w, r, err)
return
}
nonce := queryValues.Get("nonce")
if nonce == "" {
errHandler.ServeError(w, r, errors.New("nonce is empty"))
return
}
token := srv.Token()
signature2 := util.Sign(token, timestampStr, nonce)
if !security.SecureCompareString(signature1, signature2) {
err := fmt.Errorf("check signature failed, input: %s, local: %s", signature1, signature2)
errHandler.ServeError(w, r, err)
return
}
// 验证签名成功, 解析 MixedMessage
rawMsgXML, err := ioutil.ReadAll(r.Body)
if err != nil {
errHandler.ServeError(w, r, err)
return
}
LogInfoln("[WECHAT_DEBUG] request msg raw xml:\r\n", string(rawMsgXML))
var mixedMsg MixedMessage
if err := xml.Unmarshal(rawMsgXML, &mixedMsg); err != nil {
errHandler.ServeError(w, r, err)
return
}
// 安全考虑验证 ToUserName
haveToUserName := mixedMsg.ToUserName
wantToUserName := srv.OriId()
if wantToUserName != "" && !security.SecureCompareString(haveToUserName, wantToUserName) {
err := fmt.Errorf("the Message's ToUserName mismatch, have: %s, want: %s", haveToUserName, wantToUserName)
errHandler.ServeError(w, r, err)
return
}
// 成功, 交给 MessageHandler
req := &Request{
Token: token,
HttpRequest: r,
QueryValues: queryValues,
Signature: signature1,
Timestamp: timestamp,
Nonce: nonce,
EncryptType: encryptType,
RawMsgXML: rawMsgXML,
MixedMsg: &mixedMsg,
}
srv.MessageHandler().ServeMessage(w, req)
default: // 未知的加密类型
err := errors.New("unknown encrypt_type: " + encryptType)
errHandler.ServeError(w, r, err)
return
}
case "GET": // 验证回调 url 有效性
signature1 := queryValues.Get("signature")
if signature1 == "" {
errHandler.ServeError(w, r, errors.New("signature is empty"))
return
}
timestamp := queryValues.Get("timestamp")
if timestamp == "" {
errHandler.ServeError(w, r, errors.New("timestamp is empty"))
return
}
nonce := queryValues.Get("nonce")
if nonce == "" {
errHandler.ServeError(w, r, errors.New("nonce is empty"))
return
}
echostr := queryValues.Get("echostr")
if echostr == "" {
errHandler.ServeError(w, r, errors.New("echostr is empty"))
return
}
signature2 := util.Sign(srv.Token(), timestamp, nonce)
if !security.SecureCompareString(signature1, signature2) {
err := fmt.Errorf("check signature failed, input: %s, local: %s", signature1, signature2)
errHandler.ServeError(w, r, err)
return
}
io.WriteString(w, echostr)
}
}