import { env } from 'cloudflare:workers'
import type { AuthRequest, OAuthHelpers } from '@cloudflare/workers-oauth-provider'
import { Hono } from 'hono'
import { Octokit } from 'octokit'
import { fetchUpstreamAuthToken, getUpstreamAuthorizeUrl, type Props } from './utils'
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: {
description: 'This is a demo MCP Remote Server using GitHub for authentication.',
logo: 'https://avatars.githubusercontent.com/u/314135?s=200&v=4',
name: 'Cloudflare GitHub MCP Server', // 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, {
headers: {
...headers,
location: getUpstreamAuthorizeUrl({
client_id: env.GITHUB_CLIENT_ID,
redirect_uri: new URL('/callback', request.url).href,
scope: 'read:user',
state: btoa(JSON.stringify(oauthReqInfo)),
upstream_url: 'https://github.com/login/oauth/authorize',
}),
},
status: 302,
})
}
/**
* 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({
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,
upstream_url: 'https://github.com/login/oauth/access_token',
})
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({
metadata: {
label: name,
},
// This will be available on this.props inside MyMCP
props: {
accessToken,
email,
login,
name,
} as Props,
request: oauthReqInfo,
scope: oauthReqInfo.scope,
userId: login,
})
return Response.redirect(redirectTo)
})
export { app as GitHubHandler }
