// GET 微信资源, 然后将微信服务器返回的 JSON 用 encoding/json 解析到 response.
//
// NOTE:
// 1. 一般不用调用这个方法, 请直接调用高层次的封装方法;
// 2. 最终的 URL == incompleteURL + access_token;
// 3. response 格式有要求, 要么是 *Error, 要么是下面结构体的指针(注意 Error 必须是第一个 Field):
// struct {
// Error
// ...
// }
func (clt *Client) GetJSON(incompleteURL string, response interface{}) (err error) {
token, err := clt.Token()
if err != nil {
return
}
hasRetried := false
RETRY:
finalURL := incompleteURL + url.QueryEscape(token)
httpResp, err := clt.HttpClient.Get(finalURL)
if err != nil {
return
}
defer httpResp.Body.Close()
if httpResp.StatusCode != http.StatusOK {
return fmt.Errorf("http.Status: %s", httpResp.Status)
}
if err = json.NewDecoder(httpResp.Body).Decode(response); err != nil {
return
}
var ErrorStructValue reflect.Value // Error
// 下面的代码对 response 有特定要求, 见此函数 NOTE
responseStructValue := reflect.ValueOf(response).Elem()
if v := responseStructValue.Field(0); v.Kind() == reflect.Struct {
ErrorStructValue = v
} else {
ErrorStructValue = responseStructValue
}
switch ErrCode := ErrorStructValue.Field(0).Int(); ErrCode {
case ErrCodeOK:
return
case ErrCodeAccessTokenExpired:
ErrMsg := ErrorStructValue.Field(1).String()
LogInfoln("[WECHAT_RETRY] err_code:", ErrCode, ", err_msg:", ErrMsg)
LogInfoln("[WECHAT_RETRY] current token:", token)
if !hasRetried {
hasRetried = true
if token, err = clt.TokenRefresh(); err != nil {
return
}
LogInfoln("[WECHAT_RETRY] new token:", token)
responseStructValue.Set(reflect.New(responseStructValue.Type()).Elem())
goto RETRY
}
LogInfoln("[WECHAT_RETRY] fallthrough, current token:", token)
fallthrough
default:
return
}
}
// 下载多媒体到 io.Writer.
func (clt *Client) downloadMediaToWriter(mediaId string, writer io.Writer) (written int64, err error) {
token, err := clt.Token()
if err != nil {
return
}
hasRetried := false
RETRY:
finalURL := "https://api.weixin.qq.com/cgi-bin/media/get?media_id=" + url.QueryEscape(mediaId) +
"&access_token=" + url.QueryEscape(token)
httpResp, err := clt.HttpClient.Get(finalURL)
if err != nil {
return
}
defer httpResp.Body.Close()
if httpResp.StatusCode != http.StatusOK {
err = fmt.Errorf("http.Status: %s", httpResp.Status)
return
}
ContentType, _, _ := mime.ParseMediaType(httpResp.Header.Get("Content-Type"))
if ContentType != "text/plain" && ContentType != "application/json" { // 返回的是媒体流
return io.Copy(writer, httpResp.Body)
}
// 返回的是错误信息
var result mp.Error
if err = json.NewDecoder(httpResp.Body).Decode(&result); err != nil {
return
}
switch result.ErrCode {
case mp.ErrCodeOK:
return // 基本不会出现
case mp.ErrCodeInvalidCredential, mp.ErrCodeAccessTokenExpired: // 失效(过期)重试一次
mp.LogInfoln("[WECHAT_RETRY] err_code:", result.ErrCode, ", err_msg:", result.ErrMsg)
mp.LogInfoln("[WECHAT_RETRY] current token:", token)
if !hasRetried {
hasRetried = true
if token, err = clt.TokenRefresh(); err != nil {
return
}
mp.LogInfoln("[WECHAT_RETRY] new token:", token)
result = mp.Error{}
goto RETRY
}
mp.LogInfoln("[WECHAT_RETRY] fallthrough, current token:", token)
fallthrough
default:
err = &result
return
}
}
func (clt *Client) getJSON(url string, response interface{}) (err error) {
httpResp, err := clt.httpClient().Get(url)
if err != nil {
return
}
defer httpResp.Body.Close()
if httpResp.StatusCode != http.StatusOK {
return fmt.Errorf("http.Status: %s", httpResp.Status)
}
return json.NewDecoder(httpResp.Body).Decode(response)
}
// 从微信服务器获取 access_token.
// 同一时刻只能一个 goroutine 进入, 防止没必要的重复获取.
func (srv *DefaultAccessTokenServer) getToken() (token accessTokenInfo, cached bool, err error) {
srv.tokenGet.Lock()
defer srv.tokenGet.Unlock()
timeNowUnix := time.Now().Unix()
// 在收敛周期内直接返回最近一次获取的 access_token,
// 这里的收敛时间设定为2秒, 因为在同一个进程内, 收敛周期为2个http周期
if n := srv.tokenGet.LastTimestamp; n <= timeNowUnix && timeNowUnix < n+2 {
// 因为只有成功获取后才会更新 srv.tokenGet.LastTimestamp, 所以这些都是有效数据
token = accessTokenInfo{
Token: srv.tokenGet.LastTokenInfo.Token,
ExpiresIn: srv.tokenGet.LastTokenInfo.ExpiresIn - timeNowUnix + n,
}
cached = true
return
}
_url := "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=" + url.QueryEscape(srv.appId) +
"&secret=" + url.QueryEscape(srv.appSecret)
httpResp, err := srv.httpClient.Get(_url)
if err != nil {
srv.tokenCache.Lock()
srv.tokenCache.Token = ""
srv.tokenCache.Unlock()
return
}
defer httpResp.Body.Close()
if httpResp.StatusCode != http.StatusOK {
srv.tokenCache.Lock()
srv.tokenCache.Token = ""
srv.tokenCache.Unlock()
err = fmt.Errorf("http.Status: %s", httpResp.Status)
return
}
var result struct {
Error
accessTokenInfo
}
if err = json.NewDecoder(httpResp.Body).Decode(&result); err != nil {
srv.tokenCache.Lock()
srv.tokenCache.Token = ""
srv.tokenCache.Unlock()
return
}
if result.ErrCode != ErrCodeOK {
srv.tokenCache.Lock()
srv.tokenCache.Token = ""
srv.tokenCache.Unlock()
err = &result.Error
return
}
// 由于网络的延时, access_token 过期时间留了一个缓冲区
switch {
case result.ExpiresIn > 31556952: // 60*60*24*365.2425
srv.tokenCache.Lock()
srv.tokenCache.Token = ""
srv.tokenCache.Unlock()
err = errors.New("expires_in too large: " + strconv.FormatInt(result.ExpiresIn, 10))
return
case result.ExpiresIn > 60*60:
result.ExpiresIn -= 60 * 10
case result.ExpiresIn > 60*30:
result.ExpiresIn -= 60 * 5
case result.ExpiresIn > 60*5:
result.ExpiresIn -= 60
case result.ExpiresIn > 60:
result.ExpiresIn -= 10
default:
srv.tokenCache.Lock()
srv.tokenCache.Token = ""
srv.tokenCache.Unlock()
err = errors.New("expires_in too small: " + strconv.FormatInt(result.ExpiresIn, 10))
return
}
// 更新 tokenGet 信息
srv.tokenGet.LastTokenInfo = result.accessTokenInfo
srv.tokenGet.LastTimestamp = timeNowUnix
// 更新缓存
srv.tokenCache.Lock()
srv.tokenCache.Token = result.accessTokenInfo.Token
srv.tokenCache.Unlock()
token = result.accessTokenInfo
return
}
// 用 encoding/json 把 request marshal 为 JSON, 放入 http 请求的 body 中,
// POST 到微信服务器, 然后将微信服务器返回的 JSON 用 encoding/json 解析到 response.
//
// NOTE:
// 1. 一般不用调用这个方法, 请直接调用高层次的封装方法;
// 2. 最终的 URL == incompleteURL + access_token;
// 3. response 格式有要求, 要么是 *Error, 要么是下面结构体的指针(注意 Error 必须是第一个 Field):
// struct {
// Error
// ...
// }
func (clt *Client) PostJSON(incompleteURL string, request interface{}, response interface{}) (err error) {
buf := textBufferPool.Get().(*bytes.Buffer)
buf.Reset()
defer textBufferPool.Put(buf)
if err = json.NewEncoder(buf).Encode(request); err != nil {
return
}
requestBytes := buf.Bytes()
token, err := clt.Token()
if err != nil {
return
}
hasRetried := false
RETRY:
finalURL := incompleteURL + url.QueryEscape(token)
httpResp, err := clt.HttpClient.Post(finalURL, "application/json; charset=utf-8", bytes.NewReader(requestBytes))
if err != nil {
return
}
defer httpResp.Body.Close()
if httpResp.StatusCode != http.StatusOK {
return fmt.Errorf("http.Status: %s", httpResp.Status)
}
if err = json.NewDecoder(httpResp.Body).Decode(response); err != nil {
return
}
var ErrorStructValue reflect.Value // Error
// 下面的代码对 response 有特定要求, 见此函数 NOTE
responseStructValue := reflect.ValueOf(response).Elem()
if v := responseStructValue.Field(0); v.Kind() == reflect.Struct {
ErrorStructValue = v
} else {
ErrorStructValue = responseStructValue
}
switch ErrCode := ErrorStructValue.Field(0).Int(); ErrCode {
case ErrCodeOK:
return
case ErrCodeInvalidCredential, ErrCodeAccessTokenExpired:
ErrMsg := ErrorStructValue.Field(1).String()
LogInfoln("[WECHAT_RETRY] err_code:", ErrCode, ", err_msg:", ErrMsg)
LogInfoln("[WECHAT_RETRY] current token:", token)
if !hasRetried {
hasRetried = true
if token, err = clt.TokenRefresh(); err != nil {
return
}
LogInfoln("[WECHAT_RETRY] new token:", token)
responseStructValue.Set(reflect.New(responseStructValue.Type()).Elem())
goto RETRY
}
LogInfoln("[WECHAT_RETRY] fallthrough, current token:", token)
fallthrough
default:
return
}
}
// 从微信服务器获取 component_access_token.
// 同一时刻只能一个 goroutine 进入, 防止没必要的重复获取.
func (srv *DefaultAccessTokenServer) getToken() (token accessTokenInfo, cached bool, err error) {
srv.tokenGet.Lock()
defer srv.tokenGet.Unlock()
timeNowUnix := time.Now().Unix()
// 在收敛周期内直接返回最近一次获取的 component_access_token, 这里的收敛时间设定为4秒.
if n := srv.tokenGet.LastTimestamp; n <= timeNowUnix && timeNowUnix < n+4 {
// 因为只有成功获取后才会更新 srv.tokenGet.LastTimestamp, 所以这些都是有效数据
token = accessTokenInfo{
Token: srv.tokenGet.LastTokenInfo.Token,
ExpiresIn: srv.tokenGet.LastTokenInfo.ExpiresIn - timeNowUnix + n,
}
cached = true
return
}
verifyTicket, err := srv.verifyTicketGetter.GetComponentVerifyTicket(srv.appId)
if err != nil {
srv.tokenCache.Lock()
srv.tokenCache.Token = ""
srv.tokenCache.Unlock()
return
}
request := struct {
AppId string `json:"component_appid"`
AppSecret string `json:"component_appsecret"`
VerifyTicket string `json:"component_verify_ticket"`
}{
AppId: srv.appId,
AppSecret: srv.appSecret,
VerifyTicket: verifyTicket,
}
requestBuf := textBufferPool.Get().(*bytes.Buffer)
requestBuf.Reset()
defer textBufferPool.Put(requestBuf)
if err = json.NewEncoder(requestBuf).Encode(&request); err != nil {
srv.tokenCache.Lock()
srv.tokenCache.Token = ""
srv.tokenCache.Unlock()
return
}
url := "https://api.weixin.qq.com/cgi-bin/component/api_component_token"
httpResp, err := srv.httpClient.Post(url, "application/json; charset=utf-8", requestBuf)
if err != nil {
srv.tokenCache.Lock()
srv.tokenCache.Token = ""
srv.tokenCache.Unlock()
return
}
defer httpResp.Body.Close()
if httpResp.StatusCode != http.StatusOK {
srv.tokenCache.Lock()
srv.tokenCache.Token = ""
srv.tokenCache.Unlock()
err = fmt.Errorf("http.Status: %s", httpResp.Status)
return
}
var result struct {
mp.Error
accessTokenInfo
}
if err = json.NewDecoder(httpResp.Body).Decode(&result); err != nil {
srv.tokenCache.Lock()
srv.tokenCache.Token = ""
srv.tokenCache.Unlock()
return
}
if result.ErrCode != mp.ErrCodeOK {
srv.tokenCache.Lock()
srv.tokenCache.Token = ""
srv.tokenCache.Unlock()
err = &result.Error
return
}
// 由于网络的延时, component_access_token 过期时间留了一个缓冲区
switch {
case result.ExpiresIn > 31556952: // 60*60*24*365.2425
srv.tokenCache.Lock()
srv.tokenCache.Token = ""
srv.tokenCache.Unlock()
err = errors.New("expires_in too large: " + strconv.FormatInt(result.ExpiresIn, 10))
return
case result.ExpiresIn > 60*60:
result.ExpiresIn -= 60 * 10
case result.ExpiresIn > 60*30:
result.ExpiresIn -= 60 * 5
case result.ExpiresIn > 60*5:
result.ExpiresIn -= 60
case result.ExpiresIn > 60:
result.ExpiresIn -= 10
default:
srv.tokenCache.Lock()
srv.tokenCache.Token = ""
srv.tokenCache.Unlock()
err = errors.New("expires_in too small: " + strconv.FormatInt(result.ExpiresIn, 10))
return
}
// 更新 tokenGet 信息
srv.tokenGet.LastTokenInfo = result.accessTokenInfo
srv.tokenGet.LastTimestamp = timeNowUnix
// 更新缓存
srv.tokenCache.Lock()
srv.tokenCache.Token = result.accessTokenInfo.Token
srv.tokenCache.Unlock()
token = result.accessTokenInfo
return
}
