Using Portus to access Shared Libraries or DLLs

You can also use Portus to access existing shared libraries or DLLs without any rebuilding or reverse-engineering.

You just need to know the name of the function you wish to call, and what the input and output parmeters look like.

In this HOWTO, we'll build a piece of code into a DLL, and show you how to use Portus to expose a function within this as a Service.

Consider this simple piece of C++ code.

#include <string.h>

#ifdef WIN32
 #define PLATFORM_EXPORT __declspec( dllexport )
#else
 #define PLATFORM_EXPORT
#endif

extern "C" PLATFORM_EXPORT int calc( char operation[20], int *operand1, int *operand2, int *result );

extern "C" int calc( char operation[20], int *operand1, int *operand2, int *result ){

 if( !strcmp( operation, "add" )){
  *result = (*operand1) + (*operand2) ;
 }
 else if( !strcmp( operation, "sub" )){
  *result = (*operand1) - (*operand2) ;
 }
 else if( !strcmp( operation, "mul" )){
  *result = (*operand1) * (*operand2) ;
 }
 else if( !strcmp( operation, "div" )){
  *result = (*operand1) / (*operand2) ;
 }
 else{
  *result = 0;
  return -1;
 }

 return 0;
}

This is a simple calc method which will take a string, two integers, and return a integer based on the value of string.

For the purposes of this HOWTO, we are running Portus on Windows, and will build the above code into a Windows DLL using MS VC++.

If Portus is running on Linux, the DLL should be built there, and so on, depending on the platform.

A pre-built Windows (x86) DLL is available here

Portus must now be configured to load and run this DLL.

eally, our new DLL will be available in the system PATH. On Unix-based systems, you should change to the directory where the DLL is located, and run the command

export PATH=$PATH:$PWD

Now restart Portus in this shell.

On z/OS, ensure the load library containing the DLL is in your STEPLIB concatenation.

As Windows requires a restart before picking up a new system PATH, the simplest thing to do is copy the built DLL into the bin directory of your SOA Gateway installation. Assuming the default installation was used, this will be C:\Program Files\Risaris Limited\Portus {v.r.m}\Apache\bin\ where {v.r.m} denotes the actual Portus server version in use.

Now start your Portus Control Centre and choose one of the following methods of creating a Service based on the "calc" example

• Create ("Discover") the WebService automatically
• Define the Service manually

• In the Web Service properties, click the WSDL URL to open your the WSDL for your web service in a browser.

  

• You may import this WSDL to the WS Client of your choice, but for the pupose of this demo, we will use REST-style requests to access the DLL.

  More information about REST can be found here.

  In the browser URL box, remove the ?WSDL characters, and add the following

  "?INVOKE&operation=add&operand1=55&operand2=99"

  You should get a results something like this

  

  Congratulations! You have now accessed a DLL using Portus

• If you look back at the original C program, you can see how the name=value pairs match up to the parameters of the calc function call. Try changing the operation and operands for different mathematical operations.

  You can also use a XSL Stylesheet which can be used to change the appearance of the output XML. It is available here. As with the XRD previously, import this file into the project, and export it to the server.

  

  And then ...

  

• Now when you refresh your browser, the stylesheet will be applied and the output should look like this