Gmail Api resumable upload Rest( attachment larger than 5MB) - rest

Question

I am trying to send via Gmail Api Rest a mail with attachment larger than 5MB. To accomplish that I am trying to sent it with resumable upload. This is my code.
byte[] ba = System.IO.File.ReadAllBytes(uploadFromPath);
String base64String = Convert.ToBase64String(ba);
string url = "https://www.googleapis.com/upload/gmail/v1/users/me/messages/send?uploadType=resumable"
HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;
request.Headers.Add("Authorization", "Bearer " + token);
request.Headers.Add("X-Upload-Content-Type", "message/rfc822");
request.Headers["X-Upload-Content-Length"]= base64String.Length.ToString();
request.Method = "POST";
request.ContentType = "application/json";
request.ContentLength = body.Length;
After I make the request I am getting the location
location = res.Headers["Location"];
and after that I make the PUT request with the location.
I would like to know what should I insert inside first request Body and what should be inside second request.
I have seen this post Attaching a file using Resumable upload w/ Gmail API
but the code worked only for files smaller than 5MB. Is there anything else I should do to accomplish attchment larger than 5MB?

Answer 1

There's actually samples on the Upload Attachment docs.
Step 1: Start a resumable session
Resumable session initiation request
POST /upload/gmail/v1/users/userId/messages/send?uploadType=resumable HTTP/1.1
Host: www.googleapis.com
Authorization: Bearer your_auth_token
Content-Length: 38
Content-Type: application/json; charset=UTF-8
X-Upload-Content-Type: message/rfc822
X-Upload-Content-Length: 2000000
{
"id": string,
"threadId": string,
"labelIds": [
string
],
"snippet": string,
"historyId": unsigned long,
"payload": {
"partId": string,
"mimeType": string,
"filename": string,
"headers": [
{
"name": string,
"value": string
}
],
"body": users.messages.attachments Resource,
"parts": [
(MessagePart)
]
},
"sizeEstimate": integer,
"raw": bytes
}
Step 2: Save the resumable session URI
HTTP/1.1 200 OK
Location: https://www.googleapis.com/upload/gmail/v1/users/userId/messages/send?uploadType=resumable&upload_id=xa298sd_sdlkj2
Content-Length: 0
Step 3: Upload the file
PUT https://www.googleapis.com/upload/gmail/v1/users/userId/messages/send?uploadType=resumable&upload_id=xa298sd_sdlkj2 HTTP/1.1
Content-Length: 2000000
Content-Type: message/rfc822
bytes 0-1999999