Add Continue with Atmosphere

<script src="https://login.atmosphereaccount.com/atmosphere-login.js" defer></script>

<button
  data-atmosphere-login
  data-client-id="https://app.example.com/oauth/client-metadata.json"
  data-return-uri="https://app.example.com/auth/atmosphere/selected"
  data-app-name="Example App"
></button>

const verified = await verifyAtmosphereLoginCallback({
  url: request.url,
  publicJwk,
  expectedIssuer: "https://login.atmosphereaccount.com",
  expectedClientId,
  expectedReturnUri,
  expectedState,
  replayStore,
});

if (!verified.ok) throw new Error(verified.error);

return redirect("/oauth/start?" + new URLSearchParams({
  login_hint: verified.claims.handle || verified.claims.sub,
}));

<button
  data-atmosphere-login
  data-client-id="https://app.example.com/oauth/client-metadata.json"
  data-return-uri="https://app.example.com/auth/atmosphere/selected"
  data-scope="atproto"
  data-app-name="Example App"
  data-app-homepage="https://app.example.com"
  data-mode="redirect"
></button>

{
  "version": "atmosphere.login.v0.1",
  "apps": [
    {
      "client_id": "https://app.example.com/oauth/client-metadata.json",
      "app_name": "Example App",
      "homepage": "https://app.example.com",
      "logo_uri": "https://app.example.com/icon.png",
      "allowed_return_uris": [
        "https://app.example.com/auth/atmosphere/selected"
      ]
    }
  ]
}

Local:
client_id=http://localhost/?redirect_uri=http%3A%2F%2F127.0.0.1%3A5174%2Fauth%2Fatmosphere%2Fselected
return_uri=http://127.0.0.1:5174/auth/atmosphere/selected

Production:
client_id=https://app.example.com/oauth/client-metadata.json
return_uri=https://app.example.com/auth/atmosphere/selected

import {
  fetchAtmosphereLoginPublicJwkForToken,
  verifyAtmosphereLoginCallback,
} from "https://login.atmosphereaccount.com/atmosphere-login-server.js";

const callbackUrl = new URL(request.url);
const selectionToken = callbackUrl.searchParams.get("selection_token");
if (!selectionToken) throw new Error("Missing selection token");

const publicJwk = await fetchAtmosphereLoginPublicJwkForToken(
  selectionToken,
  "https://login.atmosphereaccount.com",
);

const result = await verifyAtmosphereLoginCallback({
  url: callbackUrl,
  publicJwk,
  expectedIssuer: "https://login.atmosphereaccount.com",
  expectedClientId: "https://app.example.com/oauth/client-metadata.json",
  expectedState: stateFromSession,
  expectedReturnUri: "https://app.example.com/auth/atmosphere/selected",
  replayStore,
});

if (!result.ok) throw new Error(result.error);
const { sub: did, handle, pds_url } = result.claims;

if (!result.ok) throw new Error(result.error);

const loginHint = result.claims.handle || result.claims.sub;
const oauthUrl = await yourAtprotoOAuthClient.authorizeUrl({
  loginHint,
  scope: "atproto",
});

return Response.redirect(oauthUrl);