Incorrect scheme in redirection when APPEND_SLASH_FOR_POSSIBLE_DIRECTORY is enabled

[segaq44]

Bug Overview

When nginx-s3-gateway listens over http behind a reverse proxy configured with https the redirection is incorrect.

Try to access https://<URL>/some/path
results in 302 http://<URL>/some/path/
but expected is 302 https://<URL>/some/path/

Expected Behavior

Redirect to https with the ending /

Steps to Reproduce the Bug

My deployment with Kubernetes:
User Agent --https--> NGINX Ingress Controller --http--> NGINX S3 Gateway

Config:

S3_STYLE = path
ALLOW_DIRECTORY_LIST = true
APPEND_SLASH_FOR_POSSIBLE_DIRECTORY = true

Environment Details

• Built from master (oss / unprivileged) (01eed95)
• Target deployment platforms : local Kubernetes
• S3 backend implementation: Netapp StorageGrid

Additional Context

From default.conf the $scheme is retrieved directly from the request.
But retrieving it from X-Froweded-Proto seems more correct in this case.

    location @trailslash {
        # 302 to request without slashes
        # Adding a ? to the end of the replacement param in `rewrite` prevents it from
        # appending the query string.
        rewrite ^ $scheme://$http_host$uri/$is_args$query_string? redirect;
    }