Using the SOA Gateway to access Shared Libraries or DLLs
You can also use the SOA Gateway 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 the SOA Gateway to expose a function within this as a Web 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 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 the SOA Gateway on Windows, and will build the above code into a Windows DLL using MS VC++.
If the SOA Gateway 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
The SOA Gateway must now be configured to load and run this DLL.
Ideally, 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 the
SOA Gateway 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\SOA Gateway {v.r.m}\Apache\bin\ where {v.r.m} denotes the actual SOA Gateway server version in use.
Now start your SOA Gateway Control Center and choose one of the following methods of creating a WebService based on the "calc" example
Download the C-source to your local disk driver from here
Start the discover process from the Configuration view by clicking the icon.
Select the DLL Driver and click .
Enter the Path where you downloaded (or compiled) the "Calc" DLL to. If it is located in a directory available on the search path, leave the Path field empty. Click
Select the demo_dll_calc.dll, click the Button
You will now associate the DLL with the source, which will be used to generate the SOA Gateway DataView. From the Connect to column's dropdown box select Source from File System.
Advance to the Connect with column, click it, then click the push-button appearing at the right hand corner
In the File Dialog popping up, navigate to the location where the C-source for the demo DLL has been downloaded to, select it
For files with an extension of .c or .h the Language will automatically be set to C. Click the button.
Progress and completion of the generation process will be shown with this dialog
The WebService has been created and is usable
Add a new Web Service. See here for more information
Add the following information
Name : "demo_dll_calc_calc"
DataView : "calcDemo"
Driver : "DLL Driver" (or equivalent on your system)
sharedLib : "demo_dll_calc.dll "( the name of the DLL you've built )
methodName : "calc"
Click to publish your changes to the server.
Save the following XRD file to disk. This is file which maps the calc functions parameters to a format that the SOA Gateway can understand.
Swtich over to your Java/Resource perspective ( see here for more info )
Right-click your project, and select
Expand and select File System. Click
Click and select the directory where you saved the above XRD. Check the XRD, and click
Back to the SOA Gateway perspective, right-click your server, and select Export Web Service Definitions to server
Select both the calcDemo files, and click
In the configuration view, Right-click your Web Service and select Refresh Web Service
This section will show you how to access our new DLL Web service.
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 the SOA Gateway
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
