97310d50c5
Introduce new example implementations to replace simple-host and simple-server: - basic-host: Reference host implementation with double-iframe sandbox pattern for secure UI isolation (outer iframe validates and relays messages, inner iframe renders untrusted tool UI via srcdoc) - basic-server-react: MCP server example demonstrating tool registration with linked UI resources and React UI using the useApp() hook Build infrastructure updates: - Add build:all script and simplify CI/pre-commit to use it - Add examples:dev for watch-mode development workflow Also change PostMessageTransport logging from info to debug level. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
87 lines
3.3 KiB
TypeScript
87 lines
3.3 KiB
TypeScript
import type { McpUiSandboxProxyReadyNotification, McpUiSandboxResourceReadyNotification } from "../../../dist/src/types";
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const ALLOWED_REFERRER_PATTERN = /^http:\/\/(localhost|127\.0\.0\.1)(:|\/|$)/;
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if (window.self === window.top) {
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throw new Error("This file is only to be used in an iframe sandbox.");
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}
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if (!document.referrer) {
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throw new Error("No referrer, cannot validate embedding site.");
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}
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if (!document.referrer.match(ALLOWED_REFERRER_PATTERN)) {
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throw new Error(
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`Embedding domain not allowed in referrer ${document.referrer}. (Consider updating the validation logic to allow your domain.)`,
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);
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}
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// Security self-test: verify iframe isolation is working correctly.
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// This MUST throw a SecurityError -- if `window.top` is accessible, the sandbox
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// configuration is dangerously broken and untrusted content could escape.
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try {
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window.top!.alert("If you see this, the sandbox is not setup securely.");
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throw "FAIL";
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} catch (e) {
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if (e === "FAIL") {
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throw new Error("The sandbox is not setup securely.");
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}
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// Expected: SecurityError confirms proper sandboxing.
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}
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// Double-iframe sandbox architecture: THIS file is the outer sandbox proxy
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// iframe on a separate origin. It creates an inner iframe for untrusted HTML
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// content. Per the specification, the Host and the Sandbox MUST have different
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// origins.
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const inner = document.createElement("iframe");
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inner.style = "width:100%; height:100%; border:none;";
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inner.setAttribute("sandbox", "allow-scripts allow-same-origin allow-forms");
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document.body.appendChild(inner);
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const RESOURCE_READY_NOTIFICATION: McpUiSandboxResourceReadyNotification["method"] =
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"ui/notifications/sandbox-resource-ready";
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const PROXY_READY_NOTIFICATION: McpUiSandboxProxyReadyNotification["method"] =
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"ui/notifications/sandbox-proxy-ready";
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// Message relay: This Sandbox (outer iframe) acts as a bidirectional bridge,
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// forwarding messages between:
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//
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// Host (parent window) ↔ Sandbox (outer frame) ↔ Guest UI (inner iframe)
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//
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// Reason: the parent window and inner iframe have different origins and can't
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// communicate directly, so the outer iframe forwards messages in both
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// directions to connect them.
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//
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// Special case: The "ui/notifications/sandbox-proxy-ready" message is
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// intercepted here (not relayed) because the Sandbox uses it to configure and
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// load the inner iframe with the Guest UI HTML content.
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window.addEventListener("message", async (event) => {
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if (event.source === window.parent) {
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// NOTE: In production you'll also want to validate `event.origin` against
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// your Host domain.
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if (event.data && event.data.method === RESOURCE_READY_NOTIFICATION) {
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const { html, sandbox } = event.data.params;
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if (typeof sandbox === "string") {
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inner.setAttribute("sandbox", sandbox);
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}
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if (typeof html === "string") {
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inner.srcdoc = html;
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}
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} else {
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if (inner && inner.contentWindow) {
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inner.contentWindow.postMessage(event.data, "*");
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}
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}
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} else if (event.source === inner.contentWindow) {
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// Relay messages from inner frame to parent window.
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window.parent.postMessage(event.data, "*");
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}
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});
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// Notify the Host that the Sandbox is ready to receive Guest UI HTML.
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window.parent.postMessage({
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jsonrpc: "2.0",
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method: PROXY_READY_NOTIFICATION,
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params: {},
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}, "*");
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