Include supported API versions in error message

pkg/core/apiversion/apiversion.go

@@ -16,17 +16,19 @@ const MinorVersion = 1
 // APIVersion is the current API Version.
 var APIVersion = Format(MajorVersion, MinorVersion)
 
+// SupportedVersions is a slice of supported versions.
+var SupportedVersions []string
+
 // SupportedVersionsJSON is an JSON array of supported versions.
 var SupportedVersionsJSON string
 
 var regexpAPIVersion = regexp.MustCompile(`^v(\d+)\.(\d+)$`)
 
 func init() {
-	var supportedVersions []string
 	for i := 0; i <= MinorVersion; i++ {
-		supportedVersions = append(supportedVersions, Format(MajorVersion, i))
+		SupportedVersions = append(SupportedVersions, Format(MajorVersion, i))
 	}
-	bytes, err := json.Marshal(supportedVersions)
+	bytes, err := json.Marshal(SupportedVersions)
 	if err != nil {
 		panic(err)
 	}

pkg/core/middleware/apiversion.go

@@ -1,40 +1,42 @@
 package middleware
 
 import (
+	"fmt"
 	"net/http"
 
 	"github.com/gorilla/mux"
 
-	"github.com/skygeario/skygear-server/pkg/core/apiversion"
 	"github.com/skygeario/skygear-server/pkg/core/handler"
 	"github.com/skygeario/skygear-server/pkg/core/skyerr"
 )
 
-var ErrIncompatibleAPIVersion = skyerr.NotFound.WithReason("IncompatibleAPIVersion").New("incompatible API version")
+var IncompatibleAPIVersion = skyerr.NotFound.WithReason("IncompatibleAPIVersion")
 
 // APIVersionMiddleware compares the API version with own version.
 type APIVersionMiddleware struct {
 	// APIVersionName tells how to extract the API version from mux.Vars.
 	APIVersionName string
-	// MajorVersion determines the supported major version.
-	// It should be apiversion.MajorVersion in normal use case.
-	MajorVersion int
-	// MinorVersion determines the supported minor version.
-	// It should be apiversion.MinorVersion in normal use case.
-	MinorVersion int
+	// SupportedVersions determines the full list of supported versions.
+	SupportedVersions []string
+	// SupportedVersionsJSON is the JSON encoding of SupportedVersions.
+	SupportedVersionsJSON string
 }
 
 func (m *APIVersionMiddleware) Handle(next http.Handler) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		apiVersion := mux.Vars(r)[m.APIVersionName]
-		major, minor, ok := apiversion.Parse(apiVersion)
 
-		if !ok || major != m.MajorVersion || minor > m.MinorVersion {
-			handler.WriteResponse(w, handler.APIResponse{
-				Error: ErrIncompatibleAPIVersion,
-			})
-			return
+		for _, supported := range m.SupportedVersions {
+			if apiVersion == supported {
+				next.ServeHTTP(w, r)
+				return
+			}
 		}
-		next.ServeHTTP(w, r)
+
+		handler.WriteResponse(w, handler.APIResponse{
+			Error: IncompatibleAPIVersion.New(
+				fmt.Sprintf("expected API versions: %s", m.SupportedVersionsJSON),
+			),
+		})
 	})
 }

pkg/core/middleware/apiversion_test.go

@@ -17,9 +17,9 @@ func TestAPIVersionMiddleware(t *testing.T) {
 		router := mux.NewRouter()
 		// own API version is v3.1
 		m := &APIVersionMiddleware{
-			APIVersionName: "api_version",
-			MajorVersion:   3,
-			MinorVersion:   1,
+			APIVersionName:        "api_version",
+			SupportedVersions:     []string{"v3.0", "v3.1"},
+			SupportedVersionsJSON: `["v3.0", "v3.1"]`,
 		}
 		router.Use(m.Handle)
 
@@ -44,7 +44,7 @@ func TestAPIVersionMiddleware(t *testing.T) {
 			{
 				"error": {
 					"code": 404,
-					"message": "incompatible API version",
+					"message": "expected API versions: [\"v3.0\", \"v3.1\"]",
 					"name": "NotFound",
 					"reason": "IncompatibleAPIVersion"
 				}