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For all Google Docs, I'm not able to download the thumbnail image from the ThumbnailLink property returned with a file response.

I always receive a '403 - Forbidden' error page with a message similar to this:

Your client does not have permission to get URL /thumbnailLink from this server.

(Client IP address: clientIP)

Unuthorized User

I try to use the class MediaDownloader.cs provided by Google and I also try to download it by using this code:

using (Stream stream = service.HttpClient.GetStreamAsync(p_DownloadUrl).Result) {
    StreamUtilities.Copy(p_WriteDelegate, stream.Read);
}

where 'service' is a DriveService (IClientService) object properly instantiated. I can use it to download the file or make any other requests. I use the 'Drive.Readonly' scope.

I didn't have any issue to download the Thumbnail for a Word, Excel, PDF, etc. documents, because these links are public and doesn't require any kind of authentication.

What I don't do correctly?

Is it possible to download the thumbnail for a Google Docs document?

mtheriault
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    Same problem here. The problem seems to appear only on google docs, not all files. It appeared relatively recently, as I could two month ago download the thumbnails of those files. – sk_ Apr 27 '14 at 21:20
  • Exactly, the request needs to be authenticated for downloading the Google Docs thumbnails, but actually the OAuth2 authentication doesn't work for this, only a Cookie based authentication will work. And in my case, this scenario is not viable. – mtheriault Apr 28 '14 at 20:03
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    I investigated the issue a bit.. Strangely, this problem doesn't seem to impact everyone. I tested with another accounts: some have the same issue, some don't and I can download the thumbnails. All requests are authenticated with the traditional "Authorization" header. Seems like an issue on google side... – sk_ Apr 29 '14 at 15:26
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    On my side, I use a service account (with delegation of authority) and I can't download any thumbnail when it's a Google Docs. – mtheriault Apr 30 '14 at 18:10
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    Same here guys... With regular files works, but Google Docs gives me "Unuthorized User", even with the permission for public – Luccas Jun 09 '14 at 12:09

3 Answers3

4

EDIT: This issue has now been fixed. See answer by Kalyan Reddy.

I also believe that this is an issue on Google's side. It makes no sense that you can download or export a file using an OAuth2 authenticated request, but not download a thumbnail of that same file. Another inconsistency is that this only affects Drive native formats such as application/vnd.google-apps.document. For example, I can get a thumbnail of document.docx, but not of the Drive document converted from it.

I was wondering how Google does it in their own apps and if I am using the API wrong. Turns out they use a private API for thumbnails:

https://googledrive.com/thumb/{file_id}
https://googledrive.com/thumb/{file_id}?width=500&height=500
https://googledrive.com/thumb/{file_id}?width=500&height=500&crop=false

This API works with the same OAuth2 token as Drive API v2.

I don't know exactly what Google's policy is on using undocumented APIs. Some of them are off limits or you need a permission to use them. This may fail your app review if you use it, but if you really need thumbnails right now, it is there. Otherwise you should wait for them to fix the issue on the public API.

Undocumented APIs also have no deprecation policy, so it might disappear without a warning. That said, I expect this one to be around for a while.

Community
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Indiganflow
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3

As far as I can tell, this is a bug with the Google Drive API. As you've stated, this problem appears only for Google Docs format documents, not uploaded files.

I am getting the exact same type of error message as described in my post.

Also as you mentioned I believe this had been working a short time ago.

The problem we're getting now didn't happen when we were using the deprecated Document List API. We're switching to the Google Drive API with OAuth2 as part of updating our marketplace application in order to be listed on the V2 Marketplace.

It has been extremely frustrating to not have any feedback from Google developers who are probably the only ones that can reply about whether this is a problem with the Drive API.

Community
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cwjos
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  • I agree with you, it's very frustrating. The Google support team is not very proactive. I also experiment a lot of issues with the new API with OAuth2... – mtheriault May 12 '14 at 12:06
1

We've recently made a change to fix this issue. Please try your code again and see if you are still getting this error. I was able to run the following code to successfully download a thumbnail of my Google Document.

# Get oauth credentials
...
# Authorize an http object
http = httplib2.Http()
http = credentials.authorize(http)

drive_service = build('drive', 'v2', http=http)

# Google Document type ID
docId = '1ns9x5BMIZAeUR-eXerqgpaHBBGkl_-_KCVpVoV5opn8'
files = drive_service.files().get(fileId=docId).execute()

thumbnailLink = files['thumbnailLink']
print 'Downloading thumbnail at: ', thumbnailLink
response, content = http.request(thumbnailLink)
print response.status

with open('thumbnail.jpg', 'wb') as f:
  f.write(content)
Kalyan Reddy
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