Preserve the original S3 endpoint scheme

s3/client_test.go

@@ -22,6 +22,7 @@ func TestParseURL_Success(t *testing.T) {
 	require.Equal(t, "us-east-1", cfg.Region)
 	require.Equal(t, "AKID", cfg.AccessKey)
 	require.Equal(t, "SECRET", cfg.SecretKey)
+	require.Equal(t, "https", cfg.Scheme)
 	require.Equal(t, "s3.us-east-1.amazonaws.com", cfg.Endpoint)
 	require.False(t, cfg.PathStyle)
 }
@@ -38,6 +39,7 @@ func TestParseURL_WithEndpoint(t *testing.T) {
 	require.Nil(t, err)
 	require.Equal(t, "my-bucket", cfg.Bucket)
 	require.Equal(t, "prefix", cfg.Prefix)
+	require.Equal(t, "https", cfg.Scheme)
 	require.Equal(t, "s3.example.com", cfg.Endpoint)
 	require.True(t, cfg.PathStyle)
 }
@@ -45,6 +47,7 @@ func TestParseURL_WithEndpoint(t *testing.T) {
 func TestParseURL_EndpointHTTP(t *testing.T) {
 	cfg, err := ParseURL("s3://AKID:SECRET@my-bucket?region=us-east-1&endpoint=http://localhost:9000")
 	require.Nil(t, err)
+	require.Equal(t, "http", cfg.Scheme)
 	require.Equal(t, "localhost:9000", cfg.Endpoint)
 	require.True(t, cfg.PathStyle)
 }
@@ -111,6 +114,11 @@ func TestConfig_BucketURL_PathStyle(t *testing.T) {
 	require.Equal(t, "https://s3.example.com/my-bucket", c.BucketURL())
 }
 
+func TestConfig_BucketURL_PathStyle_EndpointHTTP(t *testing.T) {
+	c := &Config{Scheme: "http", Endpoint: "localhost:9000", Bucket: "b", PathStyle: true}
+	require.Equal(t, "http://localhost:9000/b", c.BucketURL())
+}
+
 func TestConfig_BucketURL_VirtualHosted(t *testing.T) {
 	c := &Config{Endpoint: "s3.us-east-1.amazonaws.com", Bucket: "my-bucket", PathStyle: false}
 	require.Equal(t, "https://my-bucket.s3.us-east-1.amazonaws.com", c.BucketURL())

s3/types.go

@@ -11,6 +11,7 @@ import (
 
 // Config holds the parsed fields from an S3 URL. Use ParseURL to create one from a URL string.
 type Config struct {
+	Scheme       string // URL scheme, e.g. "https" or "http"
 	Endpoint     string // host[:port] only, e.g. "s3.us-east-1.amazonaws.com"
 	PathStyle    bool
 	Bucket       string
@@ -24,10 +25,14 @@ type Config struct {
 
 // BucketURL returns the base URL for bucket-level operations.
 func (c *Config) BucketURL() string {
-	if c.PathStyle {
+	scheme := "https"
-		return fmt.Sprintf("https://%s/%s", c.Endpoint, c.Bucket)
+	if c.Scheme != "" {
+		scheme = c.Scheme
 	}
-	return fmt.Sprintf("https://%s.%s", c.Bucket, c.Endpoint)
+	if c.PathStyle {
+		return fmt.Sprintf("%s://%s/%s", scheme, c.Endpoint, c.Bucket)
+	}
+	return fmt.Sprintf("%s://%s.%s", scheme, c.Bucket, c.Endpoint)
 }
 
 // HostHeader returns the value for the Host header.

s3/util.go

@@ -70,21 +70,29 @@ func ParseURL(s3URL string) (*Config, error) {
 		return nil, fmt.Errorf("s3: region query parameter is required")
 	}
 	endpointParam := u.Query().Get("endpoint")
+	var scheme string
 	var endpoint string
 	var pathStyle bool
 	if endpointParam != "" {
 		// Custom endpoint: strip scheme prefix to extract host[:port]
+		uep, err := url.Parse(endpointParam)
+		if err != nil {
+			return nil, fmt.Errorf("s3: invalid endpoint URL: %w", err)
+		}
+		scheme = uep.Scheme
 		ep := strings.TrimRight(endpointParam, "/")
 		ep = strings.TrimPrefix(ep, "https://")
 		ep = strings.TrimPrefix(ep, "http://")
 		endpoint = ep
 		pathStyle = true
 	} else {
+		scheme = "https"
 		endpoint = fmt.Sprintf("s3.%s.amazonaws.com", region)
 		pathStyle = false
 	}
 	disableHTTP2, _ := strconv.ParseBool(u.Query().Get("disable_http2"))
 	return &Config{
+		Scheme:       scheme,
 		Endpoint:     endpoint,
 		PathStyle:    pathStyle,
 		Bucket:       bucket,