jwt middleware

// jwtInspectMiddleware checks if a token is valid (signature and not issued before
// a not-before date) and sets requester and owners in the context.
func (client *Client) jwtInspectMiddleware(next echo.HandlerFunc) echo.HandlerFunc {
	return func(c echo.Context) error {
		var (
			ok     bool
			claims jwt.MapClaims
		)

		token, ok := c.Get("user").(*jwt.Token)
		if !ok || token == nil {
			reason := "no token"
			outputJSONSStatus(fmt.Sprintf("failed login (%s)", reason), false)

			return echo.NewHTTPError(http.StatusUnauthorized, reason)
		}

		ok = false
		if token.Claims != nil {
			claims, ok = token.Claims.(jwt.MapClaims)
		}

		if !ok {
			reason := "no claims"
			outputJSONSStatus(fmt.Sprintf("failed login (%s)", reason), false)

			return echo.NewHTTPError(http.StatusUnauthorized, reason)
		}

		requester, owners, err := client.getRequestInfo(claims)
		if err != nil {
			reason := err.Error()
			outputJSONSStatus(fmt.Sprintf("failed login (%s)", reason), false)

			return echo.NewHTTPError(http.StatusUnauthorized, reason)
		}

		c.Set("requester", requester)
		c.Set("owners", owners)

		outputJSONSStatus(fmt.Sprintf("successful login for %#v", claims), false)

		return next(c)
	}
}