Minify XML responses to improve compatibility

[jscontrino]

Description

When using the MinIO CLI with filen-s3, putObject requests fail. After debugging, I discovered the issue is related to how the MinIO XML parser handles the bucket location returned by getBucketLocation.

Details

• The filen-s3 XML response from getBucketLocation contains newlines.
• MinIO CLI does not trim these newlines when parsing the bucket location.
• As a result, MinIO interprets the location as "\n \n".
• This invalid location propagates into the Authorization header as "\n \n".
• Any subsequent putObject requests fail due to the malformed header.
• From my limited testing, AWS XML responses do not contain new lines.
• Due to AWS not having newlines, I suggest a small fix is implemented in this repository, even though technically one could also argue that the MinIO XML Parser should be fixed instead

Steps to Reproduce

1. Configure MinIO CLI to use a filen-s3 instance. mc alias set temporary http://$FILEN_S3_LOCATION $SECRET_ID $SECRET_KEY" --path on --api S3v4
2. Attempt to upload an object using putObject. mc cp test temporary/coolify --debug --insecure
3. Observe that the request fails due to an invalid Authorization header.

Failed to copy test. Put "http://localhost/test/test": net/http: invalid header field value for "Authorization"
(3) /dev/mc/cmd/cp-main.go:491 cmd.doCopySession(..) Tags: [\dev\mc\Dockerfile]
(2) /dev/mc/cmd/common-methods.go:520 cmd.uploadSourceToTargetURL(..) Tags: [\dev\mc\Dockerfile]
(1) /dev/mc/cmd/common-methods.go:213 cmd.putTargetStream(..) Tags: [temporary, http://localhost/test/test]
(0) /dev/mc/cmd/client-s3.go:1168 cmd.(*S3Client).Put(..)
Release-Tag:DEVELOPMENT.GOGET | Commit:DEVELOPMENT. | Host:DESKTOP| OS:windows | Arch:amd64 | Lang:go1.25.5 | Mem:7.3 MiB/18 MiB | Heap:7.3 MiB/11 MiB

Expected Behavior

getBucketLocation repsonse should not contain new lines.

Proposed Solution

Turn of pretty printing of XML responses, by setting pretty to false. This eliminates newlines.

Environment

• filen-s3 version: 0.3.1
• MinIO version: RELEASE.2025-08-13T08-35-41
• Tested on Linux and Windows