// DownloadToWriter 下载多媒体到 io.Writer.
// 对于视频素材, 先通过 GetVideo 得到 Video 信息, 然后通过 Video.DownloadURL 来下载
func DownloadToWriter(clt *core.Client, mediaId string, writer io.Writer) (written int64, err error) {
httpClient := clt.HttpClient
if httpClient == nil {
httpClient = http.DefaultClient
}
var request = struct {
MediaId string `json:"media_id"`
}{
MediaId: mediaId,
}
requestBodyBytes, err := json.Marshal(&request)
if err != nil {
return
}
var errorResult core.Error
// 先读取 64bytes 内容来判断返回的是不是错误信息
// {"errcode":40007,"errmsg":"invalid media_id"}
var buf = make([]byte, 64)
token, err := clt.Token()
if err != nil {
return
}
hasRetried := false
RETRY:
finalURL := "https://api.weixin.qq.com/cgi-bin/material/get_material?access_token=" + url.QueryEscape(token)
written, err = httpDownloadToWriter(httpClient, finalURL, requestBodyBytes, buf, writer, &errorResult)
if err != nil {
return
}
if written > 0 {
return
}
switch errorResult.ErrCode {
case core.ErrCodeOK:
return // 基本不会出现
case core.ErrCodeInvalidCredential, core.ErrCodeAccessTokenExpired:
retry.DebugPrintError(errorResult.ErrCode, errorResult.ErrMsg, token)
if !hasRetried {
hasRetried = true
errorResult = core.Error{}
if token, err = clt.RefreshToken(token); err != nil {
return
}
retry.DebugPrintNewToken(token)
goto RETRY
}
retry.DebugPrintFallthrough(token)
fallthrough
default:
err = &errorResult
return
}
}
// PostJSON 用 encoding/json 把 request marshal 为 JSON, HTTP 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. 一般不需要调用这个方法, 请直接调用高层次的封装函数;
// 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) {
ErrorStructValue, ErrorErrCodeValue := checkResponse(response)
bodyBuf := textBufferPool.Get().(*bytes.Buffer)
bodyBuf.Reset()
defer textBufferPool.Put(bodyBuf)
if err = json.NewEncoder(bodyBuf).Encode(request); err != nil {
return
}
requestBodyBytes := bodyBuf.Bytes()
if i := len(requestBodyBytes) - 1; i >= 0 && requestBodyBytes[i] == '\n' {
requestBodyBytes = requestBodyBytes[:i] // 去掉最后的 '\n', 这样能统一log格式, 不然可能多一个空白行
}
httpClient := clt.HttpClient
if httpClient == nil {
httpClient = http.DefaultClient
}
token, err := clt.Token()
if err != nil {
return
}
hasRetried := false
RETRY:
finalURL := incompleteURL + url.QueryEscape(token)
if err = httpPostJSON(httpClient, finalURL, requestBodyBytes, response); err != nil {
return
}
switch errCode := ErrorErrCodeValue.Int(); errCode {
case ErrCodeOK:
return
case ErrCodeInvalidCredential, ErrCodeAccessTokenExpired:
errMsg := ErrorStructValue.Field(errorErrMsgIndex).String()
retry.DebugPrintError(errCode, errMsg, token)
if !hasRetried {
hasRetried = true
ErrorStructValue.Set(errorZeroValue)
if token, err = clt.RefreshToken(token); err != nil {
return
}
retry.DebugPrintNewToken(token)
goto RETRY
}
retry.DebugPrintFallthrough(token)
fallthrough
default:
return
}
}
// DownloadToWriter 下载多媒体到 io.Writer.
// 请注意, 视频文件不支持下载
func DownloadToWriter(clt *core.Client, mediaId string, writer io.Writer) (written int64, err error) {
httpClient := clt.HttpClient
if httpClient == nil {
httpClient = http.DefaultClient
}
var incompleteURL = "https://api.weixin.qq.com/cgi-bin/media/get?media_id=" + url.QueryEscape(mediaId) + "&access_token="
var errorResult core.Error
token, err := clt.Token()
if err != nil {
return
}
hasRetried := false
RETRY:
finalURL := incompleteURL + url.QueryEscape(token)
written, err = httpDownloadToWriter(httpClient, finalURL, writer, &errorResult)
if err != nil {
return
}
if written > 0 {
return
}
switch errorResult.ErrCode {
case core.ErrCodeOK:
return // 基本不会出现
case core.ErrCodeInvalidCredential, core.ErrCodeAccessTokenExpired:
retry.DebugPrintError(errorResult.ErrCode, errorResult.ErrMsg, token)
if !hasRetried {
hasRetried = true
errorResult = core.Error{}
if token, err = clt.RefreshToken(token); err != nil {
return
}
retry.DebugPrintNewToken(token)
goto RETRY
}
retry.DebugPrintFallthrough(token)
fallthrough
default:
err = &errorResult
return
}
}
// GetJSON HTTP 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. 一般不需要调用这个方法, 请直接调用高层次的封装函数;
// 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) {
ErrorStructValue, ErrorErrCodeValue := checkResponse(response)
httpClient := clt.HttpClient
if httpClient == nil {
httpClient = http.DefaultClient
}
token, err := clt.Token()
if err != nil {
return
}
hasRetried := false
RETRY:
finalURL := incompleteURL + url.QueryEscape(token)
if err = httpGetJSON(httpClient, finalURL, response); err != nil {
return
}
switch errCode := ErrorErrCodeValue.Int(); errCode {
case ErrCodeOK:
return
case ErrCodeInvalidCredential, ErrCodeAccessTokenExpired:
errMsg := ErrorStructValue.Field(errorErrMsgIndex).String()
retry.DebugPrintError(errCode, errMsg, token)
if !hasRetried {
hasRetried = true
ErrorStructValue.Set(errorZeroValue)
if token, err = clt.RefreshToken(token); err != nil {
return
}
retry.DebugPrintNewToken(token)
goto RETRY
}
retry.DebugPrintFallthrough(token)
fallthrough
default:
return
}
}
// PostMultipartForm 通用上传接口.
//
// --BOUNDARY
// Content-Disposition: form-data; name="FIELDNAME"; filename="FILENAME"
// Content-Type: application/octet-stream
//
// FILE-CONTENT
// --BOUNDARY
// Content-Disposition: form-data; name="FIELDNAME"
//
// JSON-DESCRIPTION
// --BOUNDARY--
//
//
// NOTE:
// 1. 一般不需要调用这个方法, 请直接调用高层次的封装函数;
// 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) PostMultipartForm(incompleteURL string, fields []MultipartFormField, response interface{}) (err error) {
ErrorStructValue, ErrorErrCodeValue := checkResponse(response)
bodyBuf := mediaBufferPool.Get().(*bytes.Buffer)
bodyBuf.Reset()
defer mediaBufferPool.Put(bodyBuf)
multipartWriter := multipart.NewWriter(bodyBuf)
for i := 0; i < len(fields); i++ {
if field := &fields[i]; field.IsFile {
partWriter, err3 := multipartWriter.CreateFormFile(field.Name, field.FileName)
if err3 != nil {
return err3
}
if _, err3 = io.Copy(partWriter, field.Value); err3 != nil {
return err3
}
} else {
partWriter, err3 := multipartWriter.CreateFormField(field.Name)
if err3 != nil {
return err3
}
if _, err3 = io.Copy(partWriter, field.Value); err3 != nil {
return err3
}
}
}
if err = multipartWriter.Close(); err != nil {
return
}
requestBodyBytes := bodyBuf.Bytes()
requestBodyType := multipartWriter.FormDataContentType()
httpClient := clt.HttpClient
if httpClient == nil {
httpClient = http.DefaultClient
}
token, err := clt.Token()
if err != nil {
return
}
hasRetried := false
RETRY:
finalURL := incompleteURL + url.QueryEscape(token)
if err = httpPostMultipartForm(httpClient, finalURL, requestBodyType, requestBodyBytes, response); err != nil {
return
}
switch errCode := ErrorErrCodeValue.Int(); errCode {
case ErrCodeOK:
return
case ErrCodeInvalidCredential, ErrCodeAccessTokenExpired:
errMsg := ErrorStructValue.Field(errorErrMsgIndex).String()
retry.DebugPrintError(errCode, errMsg, token)
if !hasRetried {
hasRetried = true
ErrorStructValue.Set(errorZeroValue)
if token, err = clt.RefreshToken(token); err != nil {
return
}
retry.DebugPrintNewToken(token)
goto RETRY
}
retry.DebugPrintFallthrough(token)
fallthrough
default:
return
}
}