REST Web Services from UniBasic

In the midst of working up some labs for Perspectives I started thinking about REST web service access from UniBasic. The lab I happened to be working-up is on SOAP based RPC web service usage, for which we have a number of working examples and implemented projects.

But in creating services for Manage 2000 internal consumption I have all but abandoned SOAP RPC in favor of the far more elegant JSON REST model. I am usually working in ASP.NET and IE DOM client land, thankfully with the prototype.js library. So the question of the day was what would REST JSON access look like from UniBasic and what are the central issues in using it?

Well in addition to all the SOAPRequest support added with the UniBasic Extensions are a couple of simple little commands for retrieving the content from a URL. Now URLs often return HTML intended for human consumption and are not very easy to parse. The JSON REST model however returns very nice orderly string serializations.

With something as simple as:

CREATE.REQUEST.RTN.CODE = createRequest(URL:"?":QS,HTTP.METHOD,HTTP.REQUEST.HANDLE)

SUBMIT.REQUEST.RTN.CODE = submitRequest(HTTP.REQUEST.HANDLE,'','',HTTP.RESPONSE.HEADERS,HTTP.RESPONSE.DATA,HTTP.RESPONSE.STATUS)

you can get orderly responses like:

HTTP.RESPONSE.DATA = {'oValItem':{'FileName':'CM', 'TableNbr':'', 'ItemId':'1024

', 'NewItemId':'1024', 'Valid':'True', 'Display':'Sears Systems, Incorporated',

'ErrorFlag':'False', 'ErrorMsg':''}}

UniData does not yet include a JSON DOM to match the XML DOM of the UniBasic Extensions, but the parsing difficulties of JSON serializations are relatively minor. And if you need to directly access JSON REST services in the middle of UniBasic code this seems like nice direct approach.

The real stumbling blocks aren't coding difficulties, but security of your application server if you open up the HTTP or HTTPS ports for UniBasic to "see" services on the Internet. One answer to this is to go through a proxy server. This also points out one of the benefits of the architecture of Manage 2000 with its ASP.NET arm which may be used in a similar manner to delegate interaction with the messy world away from your closely guarded business database into a DMZ area.