I was trying for the better part of a week now and I finally got the resumable uploads to run. It does not work how I expected it would, but it does work.
Don't Use the Drive REST API for Everything
What I learned is that the Google Drive REST API is, as far as I know, not really capable of making chunked uploads. This may be a bug or it may be by design. I may also be too stupid.
But what got me thinking was that I could not see code examples anywhere. Everybody just talked about Http
headers all the time. So this is what we're gonna do below. We'll use just the headers.
So here is how you do resumable, chunked uploads with the Google Drive REST API and Android:
0) Initialization
String accountName = "account_name";
GoogleAccountCredential credential = GoogleAccountCredential.usingOAuth2(context, Arrays.asList(SCOPES)).setBackOff(new ExponentialBackOff()).setSelectedAccountName(accountName);
1) Start a Resumable Session
Follow the rules outlined by Google in this document:
POST /upload/drive/v3/files?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: image/jpeg
X-Upload-Content-Length: 2000000
{
"name": "My File"
}
Set all the header fields just like in Google's example. Send it as a POST
request. Use your credential
variable to get the authorization token. The mime type for X-Upload-Content-Type
is not so important, it works without it too (this SO answer provides a nice function to retrieve it from a path). Set the X-Upload-Content-Length
to the total length of your file. Set Content-Type
to JSON format, since our body will provide the metadata for Google in the JSON format.
Now create your metadata body. I put in a file name and a parent. Set the Content-Length
to the length of your body
in bytes. Then write your body to the request.getOutputStream()
output stream.
URL url = new URL("https://www.googleapis.com/upload/drive/v3/files?uploadType=resumable");
HttpURLConnection request = (HttpURLConnection) url.openConnection();
request.setRequestMethod("POST");
request.setDoInput(true);
request.setDoOutput(true);
request.setRequestProperty("Authorization", "Bearer " + credential.getToken());
request.setRequestProperty("X-Upload-Content-Type", getMimeType(file.getPath()));
request.setRequestProperty("X-Upload-Content-Length", String.format(Locale.ENGLISH, "%d", file.length()));
request.setRequestProperty("Content-Type", "application/json; charset=UTF-8");
String body = "{\"name\": \"" + file.getName() + "\", \"parents\": [\"" + parentId + "\"]}";
request.setRequestProperty("Content-Length", String.format(Locale.ENGLISH, "%d", body.getBytes().length));
OutputStream outputStream = request.getOutputStream();
outputStream.write(body.getBytes());
outputStream.close();
request.connect();
2) Save the Resumable Session URI
Finally, connect()
and wait for a response. If the response code is 200
, you have successfully initiated a chunked, resumable upload. Now save the location
header URI somewhere (database, text file, whatever). You're gonna need it later.
if (request.getResponseCode() == HttpURLConnection.HTTP_OK) {
String sessionUri = request.getHeaderField("location");
}
3) Upload the File
PUT {session_uri} HTTP/1.1
Host: www.googleapis.com
Content-Length: 524288
Content-Type: image/jpeg
Content-Range: bytes 0-524287/2000000
bytes 0-524288
Put the following code in a loop, until the entire file is uploaded. After every chunk, you will get a response with code 308
and a range
header. From this range
header, you can read the next chunk start (see (4)).
Content-Type
is going to be the mime type again. Content-Length
is the number of bytes you upload in this chunk. Content-Range
needs to be of the form bytes startByte-EndByte/BytesTotal
. You put this in a PUT
request.
Then you create a FileInputStream
and set the position to your start byte (which you got from your last response range
header) and read another chunk into your buffer. This buffer is then written to the connection output stream. Finally, connect()
.
URL url = new URL(sessionUri);
HttpURLConnection request = (HttpURLConnection) url.openConnection();
request.setRequestMethod("PUT");
request.setDoOutput(true);
request.setConnectTimeout(10000);
request.setRequestProperty("Content-Type", getMimeType(file.getPath()));
long uploadedBytes = chunkSizeInMb * 1024 * 1024;
if (chunkStart + uploadedBytes > file.length()) {
uploadedBytes = (int) file.length() - chunkStart;
}
request.setRequestProperty("Content-Length", String.format(Locale.ENGLISH, "%d", uploadedBytes));
request.setRequestProperty("Content-Range", "bytes " + chunkStart + "-" + (chunkStart + uploadedBytes - 1) + "/" + file.length());
byte[] buffer = new byte[(int) uploadedBytes];
FileInputStream fileInputStream = new FileInputStream(file);
fileInputStream.getChannel().position(chunkStart);
if (fileInputStream.read(buffer, 0, (int) uploadedBytes) == -1) { /* break, return, exit*/ }
fileInputStream.close();
OutputStream outputStream = request.getOutputStream();
outputStream.write(buffer);
outputStream.close();
request.connect();
4) Handle Response
After this you will get a response with code 308
(if successful). This response contains a range
header (mentioned).
HTTP/1.1 308 Resume Incomplete
Content-Length: 0
Range: bytes=0-524287
You split this up and obtain your new chunk start byte.
String range = chunkUploadConnection.getHeaderField("range");
int chunkPosition = Long.parseLong(range.substring(range.lastIndexOf("-") + 1, range.length())) + 1;
5) The Response Code Is Not 308?!
It can happen that you get a 5xx
response. Your internet connection could fail, the file could be deleted/renamed during upload, etc. etc.
Don't worry. As long as you save your session URI and your chunk start byte, you can resume the upload anytime.
In order to do that, send a header of the following form:
PUT {session_uri} HTTP/1.1
Content-Length: 0
Content-Range: bytes */TotalFileLength
URL url = new URL(sessionUri);
HttpURLConnection request = (HttpURLConnection) url.openConnection();
request.setRequestMethod("PUT");
request.setDoOutput(true);
request.setConnectTimeout(10000);
request.setRequestProperty("Content-Length", "0");
request.setRequestProperty("Content-Range", "bytes */" + file.length());
request.connect();
You will then receive a 308
with a range
header, from which you can read the last uploaded byte (just as we did above). Take this number and start to loop again.
I hope I could help some of you. If you have any more questions, just ask in the comments and I will edit the answer.