SIF Association

This blog is run by the staff of the SIF (Schools/Systems Interoperability Framework) Association for the use of it's members and the general educational community.

It is specifically designed for those who are interested in understanding what SIF is about, where the standard is going and how Schools, Districts and State Educational Authorities will benefit.



Wednesday, August 22, 2012

Transport 'contenders': REST and SOAP/WSDL


There are currently two leading transport “contenders” in the technology space today: REST and SOAP/WSDL.  The trick for SIF has been how to leverage both effectively without fragmenting the SIF community into two isolated sets of SIF clients and services which did not interoperate with each other.

The solution chosen for SIF 3.0 consists of two clear and distinct strategies.

-       Use SOAP WSDL conveying XML message payloads where it is strongest ... in the Zone, where all data exchanges are brokered and asynchronous, the level of security that must be provided is high, and the set of SOAP tool support for the architecture is extensive

-       Leverage REST (whether conveying XML or JSON message payloads) to extend the ability to exchange SIF-compliant data to cases where the client and service are directly connected (i.e. outside the Zone).

While “SOAP/WSDL in the Zone” is a natural progression of the same functionality already supported from SIF 2.5 on, the embracing of REST technology is new to SIF.  It is being issued as a series of developer guidelines, and it utilizes REST to address use cases such as the following:

A Student Information System (SIS), or Management Information System (MIS), is a member of a SIF zone (i.e. it already has a SIF Agent which implements the SIF brokered connection to other applications).  It has an internal browser interface which end users utilize to access and enter student data.

Now add the following requirements:

-       The developers want to extend their user interface to allow teachers to securely access student data from mobile devices like an iPad rather than just a browser

-       There are small applications that only want access to the SIS/MIS data (ex: Student Contact), and have no other reason to provide themselves with SIF Agents 

-       The SIS/MIS can now add the logic to provide the SIF “RESTful Service” interface to support synchronous SIF-compliant data interchanges, allowing the development of a simple REST client conforming to the published SIF guidelines to satisfy both of the above requirements.

Many SIS/MIS have direct REST client support today ... this standardizes their support of front ends in mobile devices or communications with separate small applications.  When written to the published guidelines, these REST clients can now access any SIF-compliant SIS/MIS supporting this new interface.  The new Direct REST connection enhances rather than replaces the brokered SOAP interface the SIS/MIS is using.

The best of both worlds in other words…