fix: resolve WASM file loading issue for npx execution (closes #31)

- Enhanced database adapter to support multiple WASM file resolution strategies
- Added require.resolve() for reliable package location in npm environments
- Made better-sqlite3 an optional dependency
- Improved error handling with clear messages
- Updated version to 2.7.13
- Updated CHANGELOG and README badges

README.md

@@ -2,7 +2,7 @@
 
 [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
 [![GitHub stars](https://img.shields.io/github/stars/czlonkowski/n8n-mcp?style=social)](https://github.com/czlonkowski/n8n-mcp)
-[![Version](https://img.shields.io/badge/version-2.7.12-blue.svg)](https://github.com/czlonkowski/n8n-mcp)
+[![Version](https://img.shields.io/badge/version-2.7.13-blue.svg)](https://github.com/czlonkowski/n8n-mcp)
 [![npm version](https://img.shields.io/npm/v/n8n-mcp.svg)](https://www.npmjs.com/package/n8n-mcp)
 [![n8n version](https://img.shields.io/badge/n8n-v1.101.1-orange.svg)](https://github.com/n8n-io/n8n)
 [![Docker](https://img.shields.io/badge/docker-ghcr.io%2Fczlonkowski%2Fn8n--mcp-green.svg)](https://github.com/czlonkowski/n8n-mcp/pkgs/container/n8n-mcp)

docs/CHANGELOG.md

@@ -5,6 +5,21 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [2.7.13] - 2025-07-11
+
+### Fixed
+- **npx Execution**: Fixed WASM file resolution for sql.js when running via `npx n8n-mcp` (Issue #31)
+  - Enhanced WASM file locator to try multiple path resolution strategies
+  - Added `require.resolve()` for reliable package location in npm environments
+  - Made better-sqlite3 an optional dependency to prevent installation failures
+  - Improved error messages when sql.js fails to load
+  - The package now works correctly with `npx` without any manual configuration
+
+### Changed
+- **Database Adapter**: Improved path resolution for both local development and npm package contexts
+  - Supports various npm installation scenarios (global, local, npx cache)
+  - Better fallback handling for sql.js WebAssembly file loading
+
 ## [2.7.12] - 2025-07-10
 
 ### Updated
@@ -565,6 +580,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Basic n8n and MCP integration
 - Core workflow automation features
 
+[2.7.13]: https://github.com/czlonkowski/n8n-mcp/compare/v2.7.12...v2.7.13
 [2.7.12]: https://github.com/czlonkowski/n8n-mcp/compare/v2.7.11...v2.7.12
 [2.7.11]: https://github.com/czlonkowski/n8n-mcp/compare/v2.7.10...v2.7.11
 [2.7.10]: https://github.com/czlonkowski/n8n-mcp/compare/v2.7.8...v2.7.10

package.json

@@ -1,6 +1,6 @@
 {
   "name": "n8n-mcp",
-  "version": "2.7.12",
+  "version": "2.7.13",
   "description": "Integration between n8n workflow automation and Model Context Protocol (MCP)",
   "main": "dist/index.js",
   "bin": {
@@ -103,5 +103,8 @@
     "n8n-workflow": "^1.98.0",
     "sql.js": "^1.13.0",
     "uuid": "^10.0.0"
+  },
+  "optionalDependencies": {
+    "better-sqlite3": "^11.10.0"
   }
 }

package.runtime.json

@@ -1,6 +1,6 @@
 {
   "name": "n8n-mcp-runtime",
-  "version": "2.7.12",
+  "version": "2.7.13",
   "description": "n8n MCP Server Runtime Dependencies Only",
   "private": true,
   "dependencies": {
@@ -15,5 +15,8 @@
   },
   "engines": {
     "node": ">=16.0.0"
+  },
+  "optionalDependencies": {
+    "better-sqlite3": "^11.10.0"
   }
 }

scripts/publish-npm.sh

@@ -64,6 +64,7 @@ pkg.license = 'MIT';
 pkg.bugs = { url: 'https://github.com/czlonkowski/n8n-mcp/issues' };
 pkg.homepage = 'https://github.com/czlonkowski/n8n-mcp#readme';
 pkg.files = ['dist/**/*', 'data/nodes.db', '.env.example', 'README.md', 'LICENSE'];
+// Note: node_modules are automatically included for dependencies
 delete pkg.private; // Remove private field so we can publish
 require('fs').writeFileSync('./package.json', JSON.stringify(pkg, null, 2));
 "

scripts/test-database-adapter.js

@@ -0,0 +1,38 @@
+#!/usr/bin/env node
+
+const { createDatabaseAdapter } = require('../dist/database/database-adapter');
+const path = require('path');
+
+async function testDatabaseAdapter() {
+  console.log('Testing database adapter initialization...\n');
+  
+  const dbPath = path.join(__dirname, '../data/nodes.db');
+  console.log('Database path:', dbPath);
+  
+  try {
+    console.log('Creating database adapter...');
+    const adapter = await createDatabaseAdapter(dbPath);
+    
+    console.log('\n✅ Database adapter created successfully!');
+    
+    // Test a simple query
+    console.log('\nTesting database query...');
+    const stmt = adapter.prepare('SELECT COUNT(*) as count FROM nodes');
+    const result = stmt.get();
+    console.log(`✅ Database contains ${result.count} nodes`);
+    
+    // Check FTS5 support
+    console.log('\nChecking FTS5 support...');
+    const hasFTS5 = adapter.checkFTS5Support();
+    console.log(`FTS5 support: ${hasFTS5 ? '✅ Available' : '❌ Not available'}`);
+    
+    adapter.close();
+    console.log('\n✅ All tests passed!');
+  } catch (error) {
+    console.error('\n❌ Error:', error.message);
+    console.error('Stack:', error.stack);
+    process.exit(1);
+  }
+}
+
+testDatabaseAdapter();

scripts/test-sqljs-fallback.js

@@ -0,0 +1,43 @@
+#!/usr/bin/env node
+
+// Force sql.js usage by temporarily hiding better-sqlite3
+const Module = require('module');
+const originalRequire = Module.prototype.require;
+
+Module.prototype.require = function(id) {
+  if (id === 'better-sqlite3') {
+    throw new Error('Simulating better-sqlite3 not available (NODE_MODULE_VERSION mismatch)');
+  }
+  return originalRequire.apply(this, arguments);
+};
+
+const { createDatabaseAdapter } = require('../dist/database/database-adapter');
+const path = require('path');
+
+async function testSqlJsFallback() {
+  console.log('Testing sql.js fallback...\n');
+  
+  const dbPath = path.join(__dirname, '../data/nodes.db');
+  
+  try {
+    console.log('Creating database adapter (better-sqlite3 disabled)...');
+    const adapter = await createDatabaseAdapter(dbPath);
+    
+    console.log('\n✅ Database adapter created successfully with sql.js!');
+    
+    // Test a simple query
+    console.log('\nTesting database query...');
+    const stmt = adapter.prepare('SELECT COUNT(*) as count FROM nodes');
+    const result = stmt.get();
+    console.log(`✅ Database contains ${result.count} nodes`);
+    
+    adapter.close();
+    console.log('\n✅ sql.js fallback works correctly!');
+  } catch (error) {
+    console.error('\n❌ Error:', error.message);
+    console.error('Stack:', error.stack);
+    process.exit(1);
+  }
+}
+
+testSqlJsFallback();

scripts/test-wasm-resolution.js

@@ -0,0 +1,52 @@
+#!/usr/bin/env node
+
+const path = require('path');
+const fs = require('fs');
+
+console.log('Testing WASM file resolution...\n');
+
+// Show current environment
+console.log('Current directory:', process.cwd());
+console.log('Script directory:', __dirname);
+console.log('Node version:', process.version);
+console.log('');
+
+// Test different path resolutions
+const testPaths = [
+  // Local development path
+  path.join(__dirname, '../node_modules/sql.js/dist/sql-wasm.wasm'),
+  // When installed as npm package
+  path.join(__dirname, '../../sql.js/dist/sql-wasm.wasm'),
+  // Alternative npm package path
+  path.join(process.cwd(), 'node_modules/sql.js/dist/sql-wasm.wasm'),
+];
+
+console.log('Checking potential WASM file locations:');
+testPaths.forEach((testPath, index) => {
+  const exists = fs.existsSync(testPath);
+  console.log(`${index + 1}. ${testPath}`);
+  console.log(`   Exists: ${exists ? '✅' : '❌'}`);
+});
+
+// Try require.resolve
+console.log('\nTrying require.resolve:');
+try {
+  const wasmPath = require.resolve('sql.js/dist/sql-wasm.wasm');
+  console.log('✅ Found via require.resolve:', wasmPath);
+  console.log('   Exists:', fs.existsSync(wasmPath) ? '✅' : '❌');
+} catch (e) {
+  console.log('❌ Failed to resolve via require.resolve:', e.message);
+}
+
+// Try to find sql.js package location
+console.log('\nTrying to find sql.js package:');
+try {
+  const sqlJsPath = require.resolve('sql.js');
+  console.log('✅ Found sql.js at:', sqlJsPath);
+  const sqlJsDir = path.dirname(sqlJsPath);
+  const wasmFromSqlJs = path.join(sqlJsDir, '../dist/sql-wasm.wasm');
+  console.log('   Derived WASM path:', wasmFromSqlJs);
+  console.log('   Exists:', fs.existsSync(wasmFromSqlJs) ? '✅' : '❌');
+} catch (e) {
+  console.log('❌ Failed to find sql.js package:', e.message);
+}

src/database/database-adapter.ts

@@ -117,14 +117,53 @@ async function createBetterSQLiteAdapter(dbPath: string): Promise<DatabaseAdapte
  * Create sql.js adapter with persistence
  */
 async function createSQLJSAdapter(dbPath: string): Promise<DatabaseAdapter> {
-  const initSqlJs = require('sql.js');
+  let initSqlJs;
+  try {
+    initSqlJs = require('sql.js');
+  } catch (error) {
+    logger.error('Failed to load sql.js module:', error);
+    throw new Error('sql.js module not found. This might be an issue with npm package installation.');
+  }
   
   // Initialize sql.js
   const SQL = await initSqlJs({
     // This will look for the wasm file in node_modules
     locateFile: (file: string) => {
       if (file.endsWith('.wasm')) {
-        return path.join(__dirname, '../../node_modules/sql.js/dist/', file);
+        // Try multiple paths to find the WASM file
+        const possiblePaths = [
+          // Local development path
+          path.join(__dirname, '../../node_modules/sql.js/dist/', file),
+          // When installed as npm package
+          path.join(__dirname, '../../../sql.js/dist/', file),
+          // Alternative npm package path
+          path.join(process.cwd(), 'node_modules/sql.js/dist/', file),
+          // Try to resolve from require
+          path.join(path.dirname(require.resolve('sql.js')), '../dist/', file)
+        ];
+        
+        // Find the first existing path
+        for (const tryPath of possiblePaths) {
+          if (fsSync.existsSync(tryPath)) {
+            if (process.env.MCP_MODE !== 'stdio') {
+              logger.debug(`Found WASM file at: ${tryPath}`);
+            }
+            return tryPath;
+          }
+        }
+        
+        // If not found, try the last resort - require.resolve
+        try {
+          const wasmPath = require.resolve('sql.js/dist/sql-wasm.wasm');
+          if (process.env.MCP_MODE !== 'stdio') {
+            logger.debug(`Found WASM file via require.resolve: ${wasmPath}`);
+          }
+          return wasmPath;
+        } catch (e) {
+          // Fall back to the default path
+          logger.warn(`Could not find WASM file, using default path: ${file}`);
+          return file;
+        }
       }
       return file;
     }

test-claude-desktop-config.json

@@ -0,0 +1,13 @@
+{
+  "mcpServers": {
+    "n8n-mcp-local": {
+      "command": "node",
+      "args": ["/Users/romualdczlonkowski/Pliki/n8n-mcp/n8n-mcp/dist/mcp/index.js"],
+      "env": {
+        "MCP_MODE": "stdio",
+        "LOG_LEVEL": "error",
+        "DISABLE_CONSOLE_OUTPUT": "true"
+      }
+    }
+  }
+}