Wasabi file upload: x-amz-content-sha256

[Trapulo]

I'm using Wasabi to upload a file and I get the error "The provided 'x-amz-content-sha256' header does not match what was computed"

byte[] blob;
.....
await _blobStorage.WriteAsync(GetItemPath(ItemID), blob);

any idea?

[robinrodricks]

[ChatGPT]

That error almost always means the request you actually sent is different from the request that was signed.

Since you're using Wasabi with the AWS S3 SDK, here are the most common causes, in order:

1. Content-Type mismatch (very common)

If your presigned URL was generated with:

request.ContentType = "image/png";

then the upload must include:

Content-Type: image/png

If you generated the URL with ContentType = null, don't send a different Content-Type that gets included in the signature.

2. x-amz-content-sha256 header mismatch

This is the specific error you're getting.

If the upload request contains:

x-amz-content-sha256: ...

the value must exactly match what the signer expected.

For presigned URLs, you should generally not manually set:

x-amz-content-sha256
Authorization
x-amz-date

Let your HTTP client send only the file body and any required headers.

3. Using a different HTTP verb

If you presigned:

Verb = HttpVerb.PUT;

then you must upload with PUT, not POST.

4. Changing signed headers

If the URL was signed with headers like:

Content-Type
Host

you must send the same values.

5. Uploading differently than expected

For example, if you do:

await httpClient.PutAsync(url, new StreamContent(stream));

that's correct.

But if your library switches to multipart form data:

multipart/form-data

the signature won't match.

[robinrodricks]

Please test using v8 and let me know if this issue still persists.