Method pollGithubAccessToken

src/node/services/serverAuthService.ts:700–758

(
    flow: GithubDeviceFlow
  )

  }

  private async pollGithubAccessToken(
    flow: GithubDeviceFlow
  ): Promise<
    Result<
      | { type: "pending" }
      | { type: "slow_down"; intervalSeconds: number }
      | { type: "authorized"; accessToken: string },
      string
    >
  > {
    const response = await fetch(GITHUB_ACCESS_TOKEN_URL, {
      method: "POST",
      headers: {
        Accept: "application/json",
        "Content-Type": "application/x-www-form-urlencoded",
      },
      body: new URLSearchParams({
        client_id: MUX_SERVER_GITHUB_CLIENT_ID,
        device_code: flow.deviceCode,
        grant_type: "urn:ietf:params:oauth:grant-type:device_code",
      }),
    });

    if (!response.ok) {
      const body = await response.text().catch(() => "");
      return Err(`GitHub token polling failed (${response.status})${body ? `: ${body}` : ""}`);
    }

    const json = (await response.json()) as unknown;
    const payload = parseGithubAccessTokenResponse(json);

    if (payload.access_token) {
      return Ok({ type: "authorized", accessToken: payload.access_token });
    }

    if (payload.error === "authorization_pending") {
      return Ok({ type: "pending" });
    }

    if (payload.error === "slow_down") {
      const nextInterval = payload.interval ?? flow.intervalSeconds + 5;
      return Ok({ type: "slow_down", intervalSeconds: Math.max(1, nextInterval) });
    }

    if (payload.error === "expired_token") {
      return Err("GitHub device code expired. Start login again.");
    }

    if (payload.error === "access_denied") {
      return Err("GitHub authorization was denied.");
    }

    if (payload.error) {
      const descriptionSuffix = payload.error_description ? `: ${payload.error_description}` : "";
      return Err(`GitHub OAuth error: ${payload.error}${descriptionSuffix}`);
    }

    return Err("GitHub token polling returned an unexpected response");