Authenticate with the Battle.net OAuth 2.0 server and retrieve World of Warcraft profile data

Steps

1. Create a client at develop.battle.net — obtain a client_id and client_secret; set a redirect URI for the Authorization Code flow (or use Client Credentials for non-user data).
2. For user profile data, redirect the user to https://<REGION>.battle.net/oauth/authorize?client_id=<CLIENT_ID>&redirect_uri=<URI>&response_type=code&scope=wow.profile to obtain an authorization code.
3. Exchange the code for a token with a POST to https://<REGION>.battle.net/oauth/token with grant_type=authorization_code, the code, and HTTP Basic auth (client_id:client_secret).
4. Use the returned access_token as a Bearer token in the Authorization header for Game Data and Profile API calls.
5. Call the WoW Profile API, e.g., GET https://<REGION>.api.blizzard.com/profile/wow/character/<REALM_SLUG>/<CHARACTER_NAME>?namespace=profile-<REGION>&locale=en_US to fetch character data.
6. For non-user game data (item databases, realms, etc.), use Client Credentials flow (POST to /oauth/token with grant_type=client_credentials) which does not require user interaction.