MCP Server Tauri

/** * html2canvas library loader * * Loads the html2canvas library from node_modules and provides it as a string * that can be injected into the webview. */ import { readFileSync } from 'fs'; import { createRequire } from 'module'; // Use createRequire to resolve the path to html2canvas in node_modules const require = createRequire(import.meta.url); let html2canvasSource: string | null = null; /** Script ID used for the html2canvas library in the script registry. */ export const HTML2CANVAS_SCRIPT_ID = '__mcp_html2canvas__'; /** * Get the html2canvas library source code. * Loaded lazily and cached. */ export function getHtml2CanvasSource(): string { if (html2canvasSource === null) { // Resolve the path to html2canvas.min.js const html2canvasPath = require.resolve('html2canvas/dist/html2canvas.min.js'); html2canvasSource = readFileSync(html2canvasPath, 'utf-8'); } return html2canvasSource; } /** * Build a script that captures a screenshot using html2canvas. * Assumes html2canvas is already loaded (either via script manager or inline). */ export function buildScreenshotCaptureScript(format: 'png' | 'jpeg', quality: number): string { // Note: This script is wrapped by executeAsyncInWebview, so we don't need an IIFE return ` // Get the html2canvas function (may be on window, self, or globalThis) const html2canvasFn = typeof html2canvas !== 'undefined' ? html2canvas : (typeof window !== 'undefined' && window.html2canvas) ? window.html2canvas : (typeof self !== 'undefined' && self.html2canvas) ? self.html2canvas : (typeof globalThis !== 'undefined' && globalThis.html2canvas) ? globalThis.html2canvas : null; if (!html2canvasFn) { throw new Error('html2canvas not loaded - function not found on any global'); } // Capture the entire document const element = document.documentElement; if (!element) { throw new Error('document.documentElement is null'); } // Configure html2canvas options const options = { backgroundColor: null, scale: window.devicePixelRatio || 1, logging: false, useCORS: true, allowTaint: false, imageTimeout: 5000, }; // Capture the webview const canvas = await html2canvasFn(element, options); if (!canvas) { throw new Error('html2canvas returned null canvas'); } // Convert to data URL const mimeType = '${format}' === 'jpeg' ? 'image/jpeg' : 'image/png'; const dataUrl = canvas.toDataURL(mimeType, ${quality / 100}); if (!dataUrl || !dataUrl.startsWith('data:image/')) { throw new Error('canvas.toDataURL returned invalid result: ' + (dataUrl ? dataUrl.substring(0, 50) : 'null')); } return dataUrl; `; } /** * Build a script that injects html2canvas and captures a screenshot. * This is the legacy function that inlines the library - kept for fallback. */ export function buildScreenshotScript(format: 'png' | 'jpeg', quality: number): string { const html2canvas = getHtml2CanvasSource(); // Note: This script is wrapped by executeAsyncInWebview, so we don't need an IIFE return ` try { // Inject html2canvas if not already present // The library uses UMD and may set on globalThis, self, or window if (typeof html2canvas === 'undefined') { ${html2canvas} // After loading, html2canvas should be on globalThis/self/window } ${buildScreenshotCaptureScript(format, quality)} } catch (screenshotError) { // Re-throw with more context throw new Error('Screenshot capture failed: ' + (screenshotError.message || String(screenshotError))); } `; }