Experiencing 503 Service Unavailable during file uploads via Google Docs API - what might be the issue?

Other Questions Google docs
1

I have an application that utilizes the Google Docs API for uploading files. Until recently, everything was functioning smoothly, but I am now encountering a 503 error when attempting to upload files.

The process is as follows: initially, I create a session that provides a resumable URL (this part still works correctly). However, when I attempt to send the file contents to that URL, a 503 Service Unavailable error occurs.

Here’s how my code looks for uploading the file:

URL uploadFileUrl = new URL(resumableUploadUrl);
HttpURLConnection httpConnection = (HttpURLConnection) uploadFileUrl.openConnection();
httpConnection.addRequestProperty("client_id", OAuth2Client.CLIENT_ID);
httpConnection.addRequestProperty("client_secret", OAuth2Client.CLIENT_SECRET);
httpConnection.setRequestProperty("Authorization", "OAuth " + GetAuthToken());

httpConnection.setRequestProperty("X-Upload-Content-Length", String.valueOf(fileContents.length()));
httpConnection.setRequestProperty("X-Upload-Content-Type", "text/xml");
httpConnection.setRequestProperty("Content-Type", "text/xml");
httpConnection.setRequestProperty("Content-Length", String.valueOf(fileContents.length()));
httpConnection.setRequestProperty("Slug", fileName);

if(isUpdate)
{
    httpConnection.setRequestProperty("If-Match", "*");
    httpConnection.setRequestMethod("PUT");
}
else
{
    httpConnection.setRequestMethod("POST");
}

httpConnection.setRequestProperty("GData-Version", "3.0");
httpConnection.setRequestProperty("User-Agent", "YourAppName");

httpConnection.setUseCaches(false);
httpConnection.setDoInput(true);
httpConnection.setDoOutput(true);

DataOutputStream dataOutputStream = new DataOutputStream(httpConnection.getOutputStream());
dataOutputStream.writeBytes(fileContents);
dataOutputStream.flush();
dataOutputStream.close();

int responseCode = httpConnection.getResponseCode();
String newLocation = httpConnection.getHeaderField("location");

This code is used for both initiating the upload session and for sending the file data. I haven’t modified my code in over a year. Is it possible that recent changes to the API could be causing this issue?

2

You’re mixing headers and that’s probably confusing Google’s servers. Don’t send both OAuth2 credentials (client_id, client_secret) AND an Authorization header - pick one. For resumable uploads, just use the Authorization header with your access token. Also, change that generic User-Agent header to your actual app name. Google sometimes flags generic values. Those 503 errors usually happen when your resumable session expires between creating it and uploading. Either upload faster after creating the session, or add session validation before uploading. And heads up - GData API is basically dead. You should migrate to Drive API v3 when you can.

3

check your file size limits - google docs api’s gotten way stricter about large uploads recently. that gdata-version 3.0 header’s outdated too since they moved most stuff to drive api v3. switch to the newer drive api instead of the old docs one - it’ll probably fix those 503 errors completely.

4

Had this exact problem six months ago - turned out to be rate limiting that wasn’t obvious. Started getting random 503s during file uploads even though we hadn’t touched our code. Added retry logic with exponential backoff and found some uploads worked after waiting a bit. Google’s servers sometimes throw 503s when they’re overloaded or you’re hitting hidden rate limits. Check if it’s happening every time or just randomly, and make sure your OAuth token hasn’t expired or lost permissions. Google loves updating their backend without warning, so working code can suddenly break.