The OAuth 2.0 Specification describes four methods (flows) for obtaining access tokens
- Authorization Code (3-leggedparty) http://tools.ietf.org/html/draft-ietf-oauth-v2-21#section-4.2
- Implicit Grant http://tools.ietf.org/html/draft-ietf-oauth-v2-21#section-4.1
- Resource Owner Password Credentials http://tools.ietf.org/html/draft-ietf-oauth-v2-21#section-4.3
- Client Credentials (2-leggedparty) http://tools.ietf.org/html/draft-ietf-oauth-v2-21#section-4.4
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