OAuth2 Introduction
OAuth-2 the version 2 of the OAuth protocol (or framework). OAuth2 defines 4 roles : Resource Owner : Generally yourself/user. Resource Server : Server hosting protected data (for example Google hosting your profile and personal information). Client : Application requesting access to a resource server (it can be your PHP website, a Javascript application or a mobile application). Authorization Server : Server issuing access token to the client. This token will be used for the client to request the resource server. This server can be the same as the authorization server (same physical server and same application), and it is often the case. Application Registration Since you want to retrieve data from a resource server using OAuth2, you have to register as a client of the authorization server. Each provider is free to allow this by the method of his choice. The protocol only defines the parameters that must be specified by the clie