APLDN

[joe_blaze]

Q: Can an APL+Win workspace behind APLNext WebServices 'see' other web services?

A: Yes. The communication between two web servers is done via http-protocol requests. The source server generates the http request and the target server, assuming that it is configured to handle such a request, responds to the request and returns that response in xml-format. Either one of the interacting web services may be APLNext WebServices servers or not.

Functions in an instance of an APL+Win workspace started by APLNextWebServices can perform the same operations as those which a function in a manually-started instance of that workspace can do.

Communicating with a web server can generally be done two ways:

Via direct human action, by pointing a browser to the url of the web service.

Under program control using HTTP requests.

A function in an instance of a, possibly server-side, APL+Win workspace can communicate with a web service under program control via HTTP requests. There are various ways to create HTTP requests in APL+Win including:

The APL+Win []ni system function for 'network interface' is very flexible, but requires serious study and application skill.

The Win32 ActiveX component ADODB treats the results of an HTTP request as a record set. It also requires some study and careful application.

APLNext WebTransfer is a .Net web client application exposed as ActiveX so that APL+Win can use it is the easiest option available.

APLNext WebTransfer is included with the APLNext WebServices product. To download APLNext WebTransfer go to: http://forum.apl2000.com/viewtopic.php?t=431. This Forum topic includes a pdf-format document which provides a simple example using APLNext WebTransfer so that a (possibly server-side) APL+Win function can access (another) web service using APLNext WebTransfer to generate the HTTP requests using its 'XSend' or XASendmethod.

APLNext WebTransfer also provides methods for exchanging objects between APL+Win and a WebServer, such as XSend, XSendFile, XSendFileSegment, XSendObject, XSendSoapObject as well as asynchronous analogues of these methods.