SignatureDoesNotMatch 403 on DigitalOcean Spaces UploadFile (leading slash in path)

TL;DR

The reporter found this themselves and a second user confirmed the same fix on uploads. The maintainer confirmed this is a quirk of the underlying AWS SDK signing and planned to add a path filter in a later update.

Steps

1. A leading forward slash on the object path breaks AWS Signature V4 signing against Spaces: UploadFile('/file.txt') fails while UploadFile('file.txt') succeeds. The reporter found this themselves and a second user confirmed the same fix on uploads. Strip any leading '/' from destination paths before calling UploadFile. The maintainer confirmed this is a quirk of the underlying AWS SDK signing and planned to add a path filter in a later update.

When to use

You are seeing this: Connecting to DigitalOcean Spaces with new SpacesConnect($key, $secret, $space_name, $region) returned: "SignatureDoesNotMatch" 403. Use this skill when you run into "SignatureDoesNotMatch 403 on DigitalOcean Spaces UploadFile (leading slash in path)".

When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

Versions

No specific versions are mentioned in the source material, so treat the fix as generally applicable and check the examples against whatever you have installed.

Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.

The thread asked: Connecting to DigitalOcean Spaces with new SpacesConnect($key, $secret, $space_name, $region) returned: "SignatureDoesNotMatch" 403. Uploading a file via $space->UploadFile($path, $destination) also failed with the same SignatureDoesNotMatch error. The credentials were correct, so the signing itself was being computed over the wrong string.

The verified answer: A leading forward slash on the object path breaks AWS Signature V4 signing against Spaces: UploadFile('/file.txt') fails while UploadFile('file.txt') succeeds. The reporter found this themselves and a second user confirmed the same fix on uploads. Strip any leading '/' from destination paths before calling UploadFile. The maintainer confirmed this is a quirk of the underlying AWS SDK signing and planned to add a path filter in a later update.

Thread: https://vectle.com/threads/thr_JxSrvWn6freipJYWGdi-EQ