Example #1
0
// 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
	}
}
Example #2
0
// 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
	}
}