The External Call Helper is an AB Suite 7.0 Runtime COM+ application that handles calls from AB Suite 7.0 Runtime applications to external components defined as External Classes in the model. These External Classes can be executables, .dlls, shell commands, as well as other components. Data marshalling behavior between is defined by the configuration properties you set for the External Classes in your model.
External Call Helper controls access via the Program Runner's role. Users requiring access to external classes needs to be added to the Program Runner's role, using the Component Services applet in the Control Panel. Note that the External Call Helper uses the caller's credentials to invoke External Classes, so it is important to ensure that in addition to role membership, the caller is also provided with sufficient access rights to the files, directories and resources that you might want to access during an external call.
Using the Start command with non-administrative callers
The Start command makes use of the Program Runner role under the AB Suite 7.0 External Call Helper. To ensure that users have sufficient privileges to use the Start command, ensure they are added to this role.
To execute the Start command through a non-administrative user, additional privileges are provided explicitly. For example, if the RATL anonymous user is a non-administrative user, Start commands invoked by an anonymous connection might fail due to lack of privileges.
Consider the following example that explains the above scenario:
RATL anonymous user is a non-administrative user.
Logic implements the Start command that runs a BAT file, which in turn generates an output.txt file to a specified folder.
In this case, for the Start command to be executed, the RATL user needs to be added to the "Program Runner" role under AB Suite 7.0 External Call Helper component through the Administration Tool.
This configuration would allow the user to execute the Start command, but is not sufficient to produce the required output. It is seen that the BAT file will not generate the output.txt file. This is because, the anonymous user is not an administrator and would not have the write permission to direct the output file onto the specified folder. On providing write and execute permissions to the user on the required folder, the output.txt file is generated successfully on executing the Start command with the anonymous user.
Consider a second scenario, where the Start command needs to execute a script. The anonymous user fails to execute the script as the cscript.exe cannot be launched through a low privileged user. In this case, add the user to this program with Read & Execute permission enabled, as this would provide the required rights to run the script.