Initial QSfera import

Server/vendor/github.com/crewjam/httperr/httperr.go

@@ -0,0 +1,56 @@
+// Package httperr implements an error object that speaks HTTP.
+package httperr
+
+import (
+	"errors"
+	"net/http"
+
+	pkgerrors "github.com/pkg/errors"
+)
+
+type statusCodeAndTexter interface {
+	StatusCodeAndText() (int, string)
+}
+
+// StatusCodeAndText returns the status code and text of the error
+func StatusCodeAndText(err error) (int, string) {
+	if err == nil {
+		return http.StatusOK, http.StatusText(http.StatusOK)
+	}
+
+	err = pkgerrors.Cause(err)
+
+	var scater statusCodeAndTexter
+	if errors.As(err, &scater) {
+		return scater.StatusCodeAndText()
+	}
+
+	return http.StatusInternalServerError, http.StatusText(http.StatusInternalServerError)
+}
+
+// Writer is an interface for things that know how to write themselves
+// to an error response. This interface is implemented by Private and
+// Public to provide default error pages.
+type Writer interface {
+	error
+	WriteError(w http.ResponseWriter, r *http.Request)
+}
+
+// Write writes the specified error to w. If err is a Writer, then
+// it's WriteError method is invoked to produce the response.
+// Otherwise a generic "500 Internal Server Error" is written.
+func Write(w http.ResponseWriter, r *http.Request, err error) {
+	err = pkgerrors.Cause(err)
+
+	var errWriter Writer
+	if errors.As(err, &errWriter) {
+		errWriter.WriteError(w, r)
+		return
+	}
+
+	genericErr := Value{
+		Err:        err,
+		StatusCode: http.StatusInternalServerError,
+	}
+	genericErr.WriteError(w, r)
+}