[#583] Fix list-buckets vhs routing

The problem is that with VHS requests,
the list-buckets operation does not work
because the request is filtered on
list-objects-v1. Since list-buckets can
also have query parameters, in the end it
is necessary to distinguish list-buckets
from list-objects-v1 only by the presence
of the bucket name in the URL (provided
that the request is in VHS style).

Signed-off-by: Roman Loginov <r.loginov@yadro.com>

api/router_test.go

@@ -903,6 +903,78 @@ func TestRouterListObjectsV2Domains(t *testing.T) {
 	require.Equal(t, s3middleware.ListObjectsV2Operation, resp.Method)
 }
 
+func TestRouterListingVHS(t *testing.T) {
+	baseDomain := "domain.com"
+	baseDomainWithBkt := "bucket.domain.com"
+	chiRouter := prepareRouter(t, enableVHSDomains(baseDomain))
+	chiRouter.handler.buckets["bucket"] = &data.BucketInfo{}
+
+	for _, tc := range []struct {
+		name              string
+		host              string
+		queries           string
+		expectedOperation string
+		notSupported      bool
+	}{
+		{
+			name:              "list-object-v1 without query params",
+			host:              baseDomainWithBkt,
+			expectedOperation: s3middleware.ListObjectsV1Operation,
+		},
+		{
+			name:              "list-buckets without query params",
+			host:              baseDomain,
+			expectedOperation: s3middleware.ListBucketsOperation,
+		},
+		{
+			name: "list-objects-v1 with prefix param",
+			host: baseDomainWithBkt,
+			queries: func() string {
+				query := make(url.Values)
+				query.Set(s3middleware.QueryPrefix, "prefix")
+				return query.Encode()
+			}(),
+			expectedOperation: s3middleware.ListObjectsV1Operation,
+		},
+		{
+			name: "list-buckets with prefix param",
+			host: baseDomain,
+			queries: func() string {
+				query := make(url.Values)
+				query.Set(s3middleware.QueryPrefix, "prefix")
+				return query.Encode()
+			}(),
+			expectedOperation: s3middleware.ListBucketsOperation,
+		},
+		{
+			name: "not supported operation",
+			host: baseDomain,
+			queries: func() string {
+				query := make(url.Values)
+				query.Set("invalid", "invalid")
+				return query.Encode()
+			}(),
+			notSupported: true,
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			w := httptest.NewRecorder()
+			r := httptest.NewRequest(http.MethodGet, "/", nil)
+			r.URL.RawQuery = tc.queries
+			r.Host = tc.host
+			chiRouter.ServeHTTP(w, r)
+
+			if tc.notSupported {
+				assertAPIError(t, w, apierr.ErrNotSupported)
+				return
+			}
+
+			resp := readResponse(t, w)
+			require.Equal(t, tc.expectedOperation, resp.Method)
+		})
+	}
+}
+
 func enableVHSDomains(domains ...string) option {
 	return func(cfg *Config) {
 		setting := cfg.MiddlewareSettings.(*middlewareSettingsMock)