/**
* Code runner client - uses @mcpc-tech/code-runner-mcp npm package
*/
import { runPy, type RunPyOptions } from "@mcpc-tech/code-runner-mcp";
import { readFileSync } from "fs";
import { fileURLToPath } from "url";
import { dirname, join, resolve } from "path";
const __filename = fileURLToPath(import.meta.url);
const __dirname = dirname(__filename);
/**
* Options for running Python script files
*/
export interface RunPythonFileOptions {
/** Command line arguments to pass to the script */
args?: string[];
/** Package name mappings (import_name -> pypi_name) */
packages?: Record<string, string>;
/** Base directory for the script (default: "python") */
baseDir?: string;
/** User file paths that need to be accessible (for file system mounting) */
filePaths?: string[];
}
/**
* Convert absolute file path to Pyodide virtual path
* Determines the mount root and converts the path accordingly
*
* @param filePath - Absolute path to the file
* @returns Object with mountRoot (host path) and virtualPath (Pyodide path)
*/
function getFileSystemMapping(
filePath: string,
): { mountRoot: string; virtualPath: string } {
const absolutePath = resolve(filePath);
// Mount the parent directory of the file
// This allows Python to access the file and its siblings
const mountRoot = dirname(absolutePath);
const virtualPath = absolutePath;
return { mountRoot, virtualPath };
}
/**
* Run a Python script file using code-runner-mcp
*
* @param scriptPath - Path to the Python script (relative to baseDir)
* @param options - Execution options
* @returns The execution result
*/
export async function runPythonFile(
scriptPath: string,
options: RunPythonFileOptions = {},
): Promise<any> {
const {
args = [],
packages = {},
baseDir = "python",
filePaths = [],
} = options;
// Read the Python script
// Python files are in the python/ directory at project root
// From dist/index.js, go up one level to reach python/
const fullPath = join(__dirname, "..", baseDir, scriptPath);
const scriptContent = readFileSync(fullPath, "utf-8");
// Build wrapper code that sets sys.argv and executes the script
const wrapperCode = `
import sys
import json
# Set command line arguments
sys.argv = ['${scriptPath}'] + ${JSON.stringify(args)}
# Execute the script
${scriptContent}
`;
// Determine mount root from the first file path
// Default: parent directory of dist/ (project root when running from dist/index.js)
let mountRoot = join(__dirname, "..");
if (filePaths.length > 0) {
const mapping = getFileSystemMapping(filePaths[0]);
mountRoot = mapping.mountRoot;
}
// Execute via runPy with options
// Mount point is the same as the mount root (Pyodide will see host paths directly)
const runPyOptions: RunPyOptions = {
packages,
nodeFSMountPoint: mountRoot,
nodeFSRoot: mountRoot,
};
const stream = await runPy(wrapperCode, runPyOptions);
// Read the stream output
const reader = stream.getReader();
const decoder = new TextDecoder();
let stdout = "";
let stderr = "";
let error = "";
try {
while (true) {
const { done, value } = await reader.read();
if (done) break;
const chunk = decoder.decode(value, { stream: true });
if (chunk.startsWith("[stderr] ")) {
stderr += chunk.slice(9);
} else if (chunk.startsWith("[err]")) {
error += chunk;
} else {
stdout += chunk;
}
}
} catch (streamError) {
// Stream error means Python execution failed
return { error: String(streamError) };
}
// Check for errors
if (error) {
return { error: error.replace(/\[err\]\[py\]\s*/g, "").trim() };
}
// Parse the JSON output from the script (last line)
const lines = stdout.trim().split("\n");
const lastLine = lines[lines.length - 1];
try {
return JSON.parse(lastLine);
} catch {
return { stdout, stderr };
}
}
