A resumable Drive API upload lets an application continue a file transfer after interruption instead of restarting blindly. Track the session and acknowledged bytes carefully, preserve the source, and distinguish an incomplete response from a completed file.
Create and retain the session
Use the documented create or update upload workflow with the appropriate resumable upload type. The initial response supplies a session URI for subsequent content transfers. Record the intended file identity and source details in the application’s protected state.
Treat session URLs and credentials as sensitive operational data. Do not place them in public logs, screenshots, or support examples.
Resume according to server state
Use the documented PUT content requests and chunk requirements. If a request fails or its outcome is unknown, query the session’s status through the supported protocol before assuming no bytes arrived.
HTTP 308 Resume Incomplete means the transfer is not finished. Inspect the acknowledged Range and continue at the next byte offset; do not interpret 308 as a normal redirect or final success. A session-expired response requires the documented restart process.
Verify the final artifact
Check the terminal response and returned file ID, then verify relevant metadata and content integrity using the fields applicable to that file type. Preserve the local source until completion is established. Avoid issuing repeated independent create requests after a timeout, because names alone cannot safely reconcile possible duplicates. Follow bounded retry rules for transient errors and investigate permission, policy, or storage failures separately. Conversion into a Google format is a different outcome from storing the original binary, so specify and verify that intention explicitly.
References
- Upload file data | Google Drive | Google for Developers
- Resolve errors | Google Drive | Google for Developers
Reviewed against the linked official product guidance on November 3, 2026. Features, limits, screen labels, and access can vary by account, platform, region, and organization policy.