PASSPORT Screen Scraping Software

PASSPORT Screen Scraping Software

Screen Scraping Software for 3270, 5250 and VT Host Applications

The term ‘screen scraping’ is frequently used to describe the method for point-to-point integration at the application layer. In the case of host integration, that translates into the ability to integrate with a mainframe (3270), AS/400 (5250) or UNIX (VT) host application using screens found anywhere in the application.

Recently, Zephyr has seen a significant increase in client-based VT/100, TN3270 and 5250 screen scraping projects using the PASSPORT terminal emulation. In fact, most new Zephyr customers have required some form of point-to-point legacy integration as a contingency for migrating from their existing terminal emulator to PASSPORT.

That's probably because 'screen scraping', as its called, is hard to beat when it comes to price, reliability and risk. The simple, but effective host application integration, is inexpensive, non-intrusive and uses time-proven business logic.

At the crescendo of the dot com era, many organizations had plans to spend large amounts of money to completely re-architect host applications and their associated business processes. However, in today's bottom-line environment, management is prone to integrate existing packaged or internally developed applications with each other rather than take a substantial risk on rebuilding from scratch what already works.

The appeal of this type of integration is widespread, yet we find that many developers may or may not know exactly what it means when it comes to host connectivity. As such, we’ve included a sample flow chart that incorporates typical steps found during the development of a screen scraping project. The steps outlined above would apply regardless of whether you’re engineering a host integration solution using terminal emulation (PASSPORT WEB TO HOST® or PASSPORT PC TO HOST®) or a programmatic host integration client or server (PASSPORT Host Integration Objects).

Screen Scraping Software Solutions

Zephyr offers the PASSPORT Object Toolkit to ease programmatic host integration efforts. It is available at no cost for customers who license at least 500 units of PASSPORT via an annual subscription license.

The Zephyr line of PASSPORT terminal emulation software offers APIs to assist with screen scraping host integration projects.

Desktop Based Host Integration APIs

• HLLAPI Interface
• Object Interface
• Macro Interface

Using the host application screen display as an API, developers can quickly navigate through TN3270, TN5250, VT100/VT220/VT420 and SCO ANSI applications to locate specific screens, fields and text, and cut and paste data to and from the host session.

The APIs listed above can be used with either PASSPORT PC TO HOST® or PASSPORT WEB TO HOST®. PASSPORT PC TO HOST® is a desktop based terminal emulation product, whereas PASSPORT WEB TO HOST® is a server deployed web-based terminal emulation product.

Sample Screen Scraping Host Integration Projects

• Microsoft Access macros can be written to update information in a host application using data from an Access database with PASSPORT terminal emulation software for host access

• A PowerBuilder HLLAPI application originally written for the NetManage Rumba desktop based terminal emulator can be ported to the PASSPORT WEB TO HOST® web-based terminal emulation software

• Complex Attachmate EXTRA!® macros and applications written specifically for Attachmate EXTRA!® can be easily ported for use with PASSPORT terminal emulation software

• A corporate desktop-based application that integrates multiple applications can embed and interface a complete terminal emulation program

Screen Scraping with the HLLAPI Interface

The HLLAPI (High Level Language Application Programming Interface) Interface was originally developed by IBM in the mid 1980's and first used with the MS DOS-based IBM PC 3270 Emulation software. It has evolved over two decades to become the most widely used API to link thousands of desktop-based applications to IBM mainframe applications.

A library file (.LIB) is provided that may be linked into an application in order to use the HLLAPI interface. Only C++ applications need an explicit link to the .LIB file. HLLAPI is not an ActiveX COM object and isn't object oriented. HLLAPI provides a single function that has four parameters. The first parameter indicates which HLLAPI function to perform. PASSPORT uses either hllapi() or winhllapi () as the function name entry point.

The IBM HLLAPI DLL name is PCSHLL.DLL whereas PASSPORT uses the PASSHLL.DLL file name. When migrating an HLLAPI application to PASSPORT it's important to check:

1. The name of the HLLAPI DLL being loaded is correct (normally needs to be changed)
2. The HHLAPI application can find the HLLAPI DLL by adding the PASSPORT installation directory to the PATH environment variable
3. The HLLAPI function entry point is correct, either hllapi() or winhllapi () or something else (normally does not need to be changed).

The HLLAPI short name, which ranges from the letter 'A' to the letter 'Z', is used to identify which host session is being used.

When to Use: The HLLAPI Interface is recommended when PASSPORT is being used to replace an existing terminal emulator and an existing PC HLLAPI application. Also, third party applications may require HLLAPI screen scraping.

Screen Scraping with the Object Interface

The PASSPORT Object Interface was originally added to PASSPORT to provide the ability to convert Attachmate EXTRA!® macros to PASSPORT macros. It can also be used to run PC applications designed using the Attachmate EXTRA!® Objects. The Object Toolit is available free of charge to customers who license at least 500 units of PASSPORT via an annual subscription license.

This interface is an ActiveX COM object called PASSOBJ.DLL. There is an hierarchy of objects used for host access which includes Sessions, Session, Screen, OIA, Area, Toolbars, Toolbar, QuickPads and QuickPad. The COM object can be used for screen scraping with any programming language that can use ActiveX COM objects, including C++, Visual Basic, VB Script and Java Script. The PASSPORT Object Toolkit provides a sample VB Script application and source code.

When migrating an existing Attachmate EXTRA!® application to PASSPORT, the only change necessary is to change the name of the object used in the CreateObject () method. An Attachmate EXTRA!® application uses CreateObject ("EXTRA.SYSTEM"). For PASSPORT you would use CreateObject ("PASSPORT.SYSTEM"). The Area object can be used to select parts of the host screen, and the copy and paste methods can be used to copy data from one host session to another. The Object Interface does not have any event driven functions.

When to Use: The Object Interface is recommended in order to run existing Attachmate OLE automation applications, complex Attachmate EXTRA!® macros that have been converted to PASSPORT, or new host access applications that require an object-oriented interface for screen scraping.

Screen Scraping with the Macro Interface

The Zephyr Macro Interface, originally designed for MS DOS and later transitioned to a 32-bit platform, is used whenever a PASSPORT macro is run. The Zephyr PASSPORT macro scripting language uses the VBSCRIPT.DLL provided by Microsoft®.

The PASSPORT PASSMAC.DLL provides the interface used for screen scraping of a host application, and is an ActiveX COM object. It is one single object and all methods and properties are accessed from this one object. The macro interface can be used for screen scraping by any application that can use an ActiveX COM object, including C++, VB, VB Script, Java Script., etc. Documentation and sample source code are provided with PASSPORT in the on-line Technical Reference. The macro interface contains special event methods that can be used to tell when host screens are received or when keystrokes have been initiated by the end-user.

When to Use: The Macro Interface is recommended when a lightweight screen scraping API is needed to access a single host session with simple event functions.