"The specified module could not be found" when loaded in app running under IIS

[steve-king-ky]

Today a test server was setup and I moved a project I'm working there. It's a Node application using Express. When I tested an endpoint it failed with:

Application has thrown an uncaught exception and is terminated:
Error: The specified module could not be found.

\\?\C:\inetpub\wwwroot\PersonnelApps\b50api\node_modules\node-rfc\lib\binding\sapnwrfc.node

 The SAP NW RFC SDK could not be loaded, check the installation: http://sap.github.io/node-rfc/install.html#sap-nw-rfc-sdk-installation
    at Object.Module._extensions..node (internal/modules/cjs/loader.js:1206:18)
    at Module.load (internal/modules/cjs/loader.js:1000:32)
    at Function.Module._load (internal/modules/cjs/loader.js:899:14)
    at Module.require (internal/modules/cjs/loader.js:1042:19)
    at require (internal/modules/cjs/helpers.js:77:18)
    at Object.<anonymous> (C:\inetpub\wwwroot\PersonnelApps\b50api\node_modules\node-rfc\lib\wrapper\sapnwrfc-client.js:6:15)
    at Module._compile (internal/modules/cjs/loader.js:1156:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1176:10)
    at Module.load (internal/modules/cjs/loader.js:1000:32)
    at Function.Module._load (internal/modules/cjs/loader.js:899:14)
    at Module.require (internal/modules/cjs/loader.js:1042:19)
    at require (internal/modules/cjs/helpers.js:77:18)
    at Object.<anonymous> (C:\inetpub\wwwroot\PersonnelApps\b50api\node_modules\node-rfc\lib\index.js:6:10)
    at Module._compile (internal/modules/cjs/loader.js:1156:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1176:10)
    at Module.load (internal/modules/cjs/loader.js:1000:32)

However, when I go to the command-line and run the same code that connects to SAP via node-rfc in a small .js file using it works just fine so there's something about the context of it running under IIS that's causing the issue although I've no idea.

BTW, the line: const rfc = require("node-rfc") when running in a script under IIS, is enough to cause the program to crash.

Any suggestions? This is driving me crazy...

[bsrdjan]

Did you check prerequisites on IIS: https://github.com/SAP/node-rfc#prerequisites ?

Also if SAP NWRFC SDK is correctly installed, by running rfcexc.exe: http://sap.github.io/node-rfc/install.html#test ?

[steve-king-ky]

@bsrdjan Yes, it appears to have been installed correctly. If I execute a script from the command-line that uses node-rfc it works perfect. This error only happens when executing under IIS for some reason.

[bsrdjan]

Could it be that IIS for some reason can't access the SAP NNRFC SDK path?

To verify, I would try something like this on IIS:

// verify the IIS user
console.log(os.userInfo());
/*
{
  uid: 501,
  gid: 20,
  username: 'bsrdjan',
  homedir: '/Users/bsrdjan',
  shell: '/usr/local/bin/zsh'
}
*/

// verify SAP NWRFC SDK is on PATH
console.log(process.env.PATH)

// verify IIS can read SAP NWRFC SDK libs
// do some readfile from SAP NWRFC SDK lib here ...

[steve-king-ky]

Great idea and running it led to an unusual discovery. The user has access but the value returned by process.env.PATH does NOT contain the path to nwrfcsdk - even though it's in the PATH environment variable (Windows) on both the system and the user.

Even more odd, if I run node.exe and run the following code:

process.env.PATH

I do see the path to the SDK listed. I restarted the IIS server but it still won't pull back the correct path. I'm not sure where it's pulling it from or if it's perhaps truncating the path?

[bsrdjan]

Web servers restrict web sites' to local host paths. IIS could be configured the same way, using virtual directories etc. Perhaps this helps: https://stackoverflow.com/questions/14611015/iis7-accessing-network-share

[vullnet-kurti]

@bsrdjan
I am running in the same problem.
I downloaded windows x64 binary from here https://github.com/SAP/node-rfc/releases/tag/v1.2.0, and I'm getting the same error:

Error: The specified module could not be found.

Also if SAP NWRFC SDK is correctly installed, by running rfcexc.exe: http://sap.github.io/node-rfc/install.html#test ?

Also checked this. It is correctly installed.

This is from a simple .js file that imports node-rfc:
const rfc = require("node-rfc")

I logged process.env.PATH, and the SAP NWRFC SDK path gets listed.

Any idea why this might happen?

Thanks.

[steve-king-ky]

As far as I can tell, it’s a versioning issue. I was able to get node-rfc to work with v12.18.0 (the latest version of node when I downloaded it recently) and node-rfc v. 1.0.0. I am running in the same problem. I downloaded windows x64 binary from here https://github.com/SAP/node-rfc/releases/tag/v1.2.0<https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_SAP_node-2Drfc_releases_tag_v1.2.0&d=DwMCaQ&c=jvUANN7rYqzaQJvTqI-69lgi41yDEZ3CXTgIEaHlx7c&r=0cnh2ele5QovaKlZoZ8ilgyH2T2Y09GAxa8EnMZKmP8&m=C08JkxWU62UoShF5k1xAIODy0pqtNZxZ4qJK947fE0Y&s=0MyxZa8ST99tXlbsQ4EXx5fY4ME4-7C4BDEjOP_0cv0&e=>, and I'm getting the same error: Error: The specified module could not be found. This is from a simple .js file that imports node-rfc: const rfc = require("node-rfc") I logged process.env.PATH, and the SAP NWRFC SDK path gets listed. Any idea why this might happen?

[bsrdjan]

Sorry for the longer waiting here. I don't see a difference in node-rfc version, causing the issue.

Could it be the authorisation problem? Could it be that IIS is running with another user account, which does not have access to NWRFC SDK ?

[steve-king-ky]

No worries - thank you so much for your interest in this post, by the way. I do not think that was the issue. Once I paired version 1.0.0 of the node-rfc packge with the latest version of node.js it worked fine.

[bsrdjan]

Thanks for the update, let close the issue then. I also sent one message via LinkedIn.