s3.ErrCodeAccessDenied is missing

[aws]

s3.ErrCodeAccessDenied is missing

[diehlaws]

Hi @rittneje, thanks for reaching out to us. At present, the SDK relies on the XML body of S3's response to determine the error received, since S3 does not return a body in the response of a HEAD request the SDK cannot reliably determine the error code returned for these operations. We've reached out to the S3 team internally in the past about modeling NotFound and AccessDenied errors for HEAD operations to S3 (see aws/aws-sdk-go#2593 for more details), however since this would present a breaking change in S3's behavior they have decided not to model these errors in a way that would result in constants that can be used to handle these errors for HeadObject and HeadBucket operations.

[rittneje]

@diehlaws Can you provide a code sample as to how we should be checking for the two errors mentioned in the documentation ("no such key" and "access denied")?

[skotambkar]

@rittneje Here's a sample code showing how to check for no such key error; For Access denied exception, since we do not model the error code for it, a way would be to lookup string in the err.Error()

input := &s3.HeadObjectInput{
    Bucket: aws.String("examplebucket"),
    Key:    aws.String("HappyFace.jpg"),
}

result, err := svc.HeadObject(input)
if err != nil {
    if aerr, ok := err.(awserr.Error); ok {
        switch aerr.Code() {
        case ErrCodeNoSuchKey:
       		fmt.Println("error: no such key")
        case ErrCodeNoSuchUpload:
       		fmt.Println("error: no such upload")
        default:
           	fmt.Println(aerr.Error())
        }
    } else {
        // Print the error, cast err to awserr.Error to get the Code and
        // Message from an error.
        fmt.Println(err.Error())
    }
    return
}

fmt.Println(result)

Hope this helps. Let us know if you have any questions/feedback.

[rittneje]

Thanks for the code sample. I would request that the documentation of HeadObject be updated to more clearly explain how to check for those errors. The way it's currently written (pasted in my original comment) is too vague, in my opinion.
Also, from testing we found that we can do aerr.Code() == "Forbidden" for the "access denied" case.

[diehlaws]

Thanks for the feedback @rittneje. Unfortunately we're unable to modify the description for the HeadObject call specifically since this originates from the service's API model, however we'll look into adding a note about this in the Overview section of the s3 package's documentation.

[jmklix]

P51417825

[jmklix]

Closing issue as the documentation has been updated:

A HEAD request has the same options as a GET action on an object. The response is identical to the GET response except that there is no response body. Because of this, if the HEAD request generates an error, it returns a generic 404 Not Found or 403 Forbidden code. It is not possible to retrieve the exact exception beyond these error codes.

[github-actions]

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