SMODL – Simple MethOd Declaration Language

The human approach to Web Service development!

SMODL is a simple XML-dialect for declaring method signatures and data structures. A major design goal of SMODL is to let non-technical domain experts participate in Web Service development, allowing them to describe, develop and use Web Services. SMODL describes Web Services in a format close to a human language, while still being powerful enough to be used in real projects.

At first glance, SMODL seems similar to a Java or C# interface. However, SMODL is a modelling language and allows annotations beyond what such interfaces can express. SMODL is also language-neutral, meaning that code for any language can be generated from it. You would use SMODL to model a Web Service and then generate e.g. Java or C# to implement it.

SMODL is not WSDL! The primary goal of SMODL is to be understandable by humans, something rarely claimed for WSDL. However, if required, a SMODL model can be translated to WSDL to deploy the Web Service on standard and non-proprietary platforms.

SMODL is not IDL either! SMODL can not describe complex bindings between objects like IDL. By design, SMODL avoids this complexity and focus on Web Services.

A SMODL model is used by Smodl run-time engine to generate and run Smodl Services. A Smodl Service is a Web Service which in addition to SOAP also includes JSON-RPC and XML-RPC bindings. Another advantage of the Smodl Service is its ability to provide secure, role-based access.

Initially, SMODL was developed by RUnit Software for internal use in 2004 in response to the lack of simple tools for working with Web Services. The original motivation for SMODL was

  • let non-technical business and domain experts understand a Web Service, allowing them to mark things which doesn't make sense from their point-of-view and suggest improvements;
  • make changes to a Web Service simple and safe by generating as much code from a model as possible, including code to be used to access the Web Service.

As work continued through 2005 – 2011, SMODL also turned out to be a simple tool for trained programmers to quickly prototype and develop Web Services, as well as a good starting-point to generate code for a variety of clients, including AJAX-applications and mobile devices.