// Exchange converts an authorization code into a token.
//
// It is used after a resource provider redirects the user back
// to the Redirect URI (the URL obtained from AuthCodeURL).
//
// The HTTP client to use is derived from the context.
// If a client is not provided via the context, http.DefaultClient is used.
//
// The code will be in the *http.Request.FormValue("code"). Before
// calling Exchange, be sure to validate FormValue("state").
func (c *Config) Exchange(ctx context.Context, code string) (*Token, error) {
baseParams := url.Values{
"grant_type": {"authorization_code"},
"code": {code},
"redirect_uri": internal.CondVal(c.RedirectURL),
"scope": internal.CondVal(strings.Join(c.Scopes, " ")),
}
return retrieveToken(ctx, c, c.getParams(baseParams))
}
// PasswordCredentialsToken converts a resource owner username and password
// pair into a token.
//
// Per the RFC, this grant type should only be used "when there is a high
// degree of trust between the resource owner and the client (e.g., the client
// is part of the device operating system or a highly privileged application),
// and when other authorization grant types are not available."
// See https://tools.ietf.org/html/rfc6749#section-4.3 for more info.
//
// The HTTP client to use is derived from the context.
// If nil, http.DefaultClient is used.
func (c *Config) PasswordCredentialsToken(ctx context.Context, username, password string) (*Token, error) {
return retrieveToken(ctx, c, url.Values{
"grant_type": {"password"},
"username": {username},
"password": {password},
"scope": internal.CondVal(strings.Join(c.Scopes, " ")),
})
}
// AuthCodeURL returns a URL to OAuth 2.0 provider's consent page
// that asks for permissions for the required scopes explicitly.
//
// State is a token to protect the user from CSRF attacks. You must
// always provide a non-zero string and validate that it matches the
// the state query parameter on your redirect callback.
// See http://tools.ietf.org/html/rfc6749#section-10.12 for more info.
//
// Opts may include AccessTypeOnline or AccessTypeOffline, as well
// as ApprovalForce.
func (c *Config) AuthCodeURL(state string, opts ...AuthCodeOption) string {
var buf bytes.Buffer
buf.WriteString(c.Endpoint.AuthURL)
v := url.Values{
"response_type": {"code"},
"client_id": {c.ClientID},
"redirect_uri": internal.CondVal(c.RedirectURL),
"scope": internal.CondVal(strings.Join(c.Scopes, " ")),
"state": internal.CondVal(state),
}
for _, opt := range opts {
opt.setValue(v)
}
if strings.Contains(c.Endpoint.AuthURL, "?") {
buf.WriteByte('&')
} else {
buf.WriteByte('?')
}
buf.WriteString(v.Encode())
return buf.String()
}