How to call local .dll files in Electron App

In Electron, calling local .dll files can be implemented in two primary ways: using the ffi-napi library for Node.js or through the edge-js library.

Method One: Using the ffi-napi Library

ffi-napi is a Node.js Foreign Function Interface (FFI) library that enables calling C language Dynamic Link Libraries (DLLs) from Node.js code. The main steps involve:

1. Install ffi-napi and ref-napi Libraries: In your Electron project, install these libraries via npm:

   bash
   npm install ffi-napi ref-napi

2. Load the DLL File: Use ffi-napi to define and load functions from the DLL. You must be aware of the function signature, including input and output types.

   javascript
   const ffi = require('ffi-napi');
   const ref = require('ref-napi');
   
   // Define parameter types
   const int = ref.types.int;
   
   // Load the DLL
   const myLibrary = ffi.Library('path/to/your/library.dll', {
     'myFunction': [ int, [ int ] ]
   });
   
   // Call the function
   const result = myLibrary.myFunction(123);
   console.log('Result:', result);

Method Two: Using the edge-js Library

edge-js allows executing .NET code, making it ideal for DLLs written in .NET.

1. Install edge-js: Install the edge-js library via npm:

   bash
   npm install edge-js

2. Call Methods in the DLL: Use edge-js to load and invoke methods from the DLL file.

   javascript
   const edge = require('edge-js');
   
   const helloWorld = edge.func({
     assemblyFile: 'path/to/your.dll',
     typeName: 'YourNamespace.ClassName',
     methodName: 'Method' // This is a static method
   });
   
   helloWorld(null, function (error, result) {
     if (error) throw error;
     console.log(result);
   });

Example

Suppose you have a DLL file MathLibrary.dll containing a method Add for addition operations. Here's an example using ffi-napi:

javascript
const ffi = require('ffi-napi');

const mathLibrary = ffi.Library('MathLibrary.dll', {
  'Add': ['int', ['int', 'int']]
});

const sum = mathLibrary.Add(5, 8);
console.log('Sum:', sum);  // Output should be 13

Important Notes

• Ensure the DLL file matches your project's platform (e.g., 32-bit or 64-bit).
• You must have sufficient knowledge of the functions in the DLL, particularly their parameter types and return types.
• When deploying an Electron application, ensure the DLL file is included in the final packaged output.

By employing these two methods, you can effectively integrate local DLL files into Electron applications, which is highly valuable for extending functionality.