github-handler.ts•3.67 kB
import type { AuthRequest, OAuthHelpers } from '@cloudflare/workers-oauth-provider'
import { Hono } from 'hono'
import { Octokit } from 'octokit'
import { fetchUpstreamAuthToken, getUpstreamAuthorizeUrl, Props } from './utils'
import { env } from 'cloudflare:workers'
import { clientIdAlreadyApproved, parseRedirectApproval, renderApprovalDialog } from './workers-oauth-utils'
const app = new Hono<{ Bindings: Env & { OAUTH_PROVIDER: OAuthHelpers } }>()
app.get('/authorize', async (c) => {
const oauthReqInfo = await c.env.OAUTH_PROVIDER.parseAuthRequest(c.req.raw)
const { clientId } = oauthReqInfo
if (!clientId) {
return c.text('Invalid request', 400)
}
if (await clientIdAlreadyApproved(c.req.raw, oauthReqInfo.clientId, env.COOKIE_ENCRYPTION_KEY)) {
return redirectToGithub(c.req.raw, oauthReqInfo)
}
return renderApprovalDialog(c.req.raw, {
client: await c.env.OAUTH_PROVIDER.lookupClient(clientId),
server: {
name: "Cloudflare GitHub MCP Server",
logo: "https://avatars.githubusercontent.com/u/314135?s=200&v=4",
description: 'This is a demo MCP Remote Server using GitHub for authentication.', // optional
},
state: { oauthReqInfo }, // arbitrary data that flows through the form submission below
})
})
app.post('/authorize', async (c) => {
// Validates form submission, extracts state, and generates Set-Cookie headers to skip approval dialog next time
const { state, headers } = await parseRedirectApproval(c.req.raw, env.COOKIE_ENCRYPTION_KEY)
if (!state.oauthReqInfo) {
return c.text('Invalid request', 400)
}
return redirectToGithub(c.req.raw, state.oauthReqInfo, headers)
})
async function redirectToGithub(request: Request, oauthReqInfo: AuthRequest, headers: Record<string, string> = {}) {
return new Response(null, {
status: 302,
headers: {
...headers,
location: getUpstreamAuthorizeUrl({
upstream_url: 'https://github.com/login/oauth/authorize',
scope: 'read:user',
client_id: env.GITHUB_CLIENT_ID,
redirect_uri: new URL('/callback', request.url).href,
state: btoa(JSON.stringify(oauthReqInfo)),
}),
},
})
}
/**
* OAuth Callback Endpoint
*
* This route handles the callback from GitHub after user authentication.
* It exchanges the temporary code for an access token, then stores some
* user metadata & the auth token as part of the 'props' on the token passed
* down to the client. It ends by redirecting the client back to _its_ callback URL
*/
app.get("/callback", async (c) => {
// Get the oathReqInfo out of KV
const oauthReqInfo = JSON.parse(atob(c.req.query("state") as string)) as AuthRequest;
if (!oauthReqInfo.clientId) {
return c.text("Invalid state", 400);
}
// Exchange the code for an access token
const [accessToken, errResponse] = await fetchUpstreamAuthToken({
upstream_url: "https://github.com/login/oauth/access_token",
client_id: c.env.GITHUB_CLIENT_ID,
client_secret: c.env.GITHUB_CLIENT_SECRET,
code: c.req.query("code"),
redirect_uri: new URL("/callback", c.req.url).href,
});
if (errResponse) return errResponse;
// Fetch the user info from GitHub
const user = await new Octokit({ auth: accessToken }).rest.users.getAuthenticated();
const { login, name, email } = user.data;
// Return back to the MCP client a new token
const { redirectTo } = await c.env.OAUTH_PROVIDER.completeAuthorization({
request: oauthReqInfo,
userId: login,
metadata: {
label: name,
},
scope: oauthReqInfo.scope,
// This will be available on this.props inside MyMCP
props: {
login,
name,
email,
accessToken,
} as Props,
});
return Response.redirect(redirectTo);
});
export { app as GitHubHandler }