使用HTTP请求将电子邮件发送到Gmail API时出错

Question

我正在尝试使用带有HTTP请求的Gmail API发送电子邮件。 参考链接：https://developers.google.com/gmail/api/v1/reference/users/messages/send

我调用API的示例代码：-

/*HTTP Request*/
POST https://www.googleapis.com/gmail/v1/users/{userId}/messages/send

/*Headers:*/
Authorization: Bearer {accesstoken}
Content-Type: message/rfc822

/*Request body*/
{"raw":"RnJvbTogamhvbndpbHNvbi5lY3Npb25AZ21haWwuY29tIApUbzogaW1yYWFuQGVjc2lvbi5jb20gClN1YmplY3Q6IFNheWluZyBIZWxsbyAKRGF0ZTogMDYtQXVnLTIwMTggMTM6NTA6MzEgKzA1IApNZXNzYWdlLUlEOiA8MTIzNEBsb2NhbC5tYWNoaW5lLmV4YW1wbGU-CgpUaGlzIGlzIGEgbWVzc2FnZSBqdXN0IHRvIHNheSBoZWxsby4gU28sICJIZWxsbyIu"}

---

发起请求后，API返回以下json响应：

{ "error": { "errors": [ { "domain": "global", "reason": "wrongUrlForUpload", "message": "Uploads must be sent to the upload URL. Re-send this request to https://www.googleapis.com/upload/gmail/v1/users/{userId}/messages/send" } ], "code": 400, "message": "Uploads must be sent to the upload URL. Re-send this request to https://www.googleapis.com/upload/gmail/v1/users/{userId}/messages/send" } }

注意-我没有在电子邮件中传递任何附件。

请让我知道我在请求中做错了。