Merge pull request #138 from lumost/returnErrorCause

UnWrap HttpErrors in pop middleware and return them.

default_context.go

@@ -103,13 +103,13 @@ func (d *DefaultContext) Render(status int, rr render.Renderer) error {
 		bb := &bytes.Buffer{}
 		err := rr.Render(bb, data)
 		if err != nil {
-			return httpError{Status: 500, Cause: errors.WithStack(err)}
+			return HTTPError{Status: 500, Cause: errors.WithStack(err)}
 		}
 		d.Response().Header().Set("Content-Type", rr.ContentType())
 		d.Response().WriteHeader(status)
 		_, err = io.Copy(d.Response(), bb)
 		if err != nil {
-			return httpError{Status: 500, Cause: errors.WithStack(err)}
+			return HTTPError{Status: 500, Cause: errors.WithStack(err)}
 		}
 		return nil
 	}
@@ -155,7 +155,7 @@ func (d *DefaultContext) LogFields(values map[string]interface{}) {
 }
 
 func (d *DefaultContext) Error(status int, err error) error {
-	return httpError{Status: status, Cause: errors.WithStack(err)}
+	return HTTPError{Status: status, Cause: errors.WithStack(err)}
 }
 
 // Websocket returns an upgraded github.com/gorilla/websocket.Conn

errors.go

@@ -9,12 +9,13 @@ import (
 	"github.com/pkg/errors"
 )
 
-type httpError struct {
+// HTTPError a typed error returned by http Handlers and used for choosing error handlers
+type HTTPError struct {
 	Status int   `json:"status"`
 	Cause  error `json:"error"`
 }
 
-func (h httpError) Error() string {
+func (h HTTPError) Error() string {
 	return h.Cause.Error()
 }
 

handler.go

@@ -4,6 +4,7 @@ import (
 	"net/http"
 
 	"github.com/gorilla/mux"
+	"github.com/pkg/errors"
 )
 
 // Handler is the basis for all of Buffalo. A Handler
@@ -56,8 +57,11 @@ func (a *App) handlerToHandler(info RouteInfo, h Handler) http.Handler {
 
 		if err != nil {
 			status := 500
-			if e, ok := err.(httpError); ok {
-				status = e.Status
+			// unpack root cause and check for HTTPError
+			cause := errors.Cause(err)
+			httpError, ok := cause.(HTTPError)
+			if ok {
+				status = httpError.Status
 			}
 			eh := a.ErrorHandlers.Get(status)
 			err = eh(status, err, c)