func Authorize(app *App, permissions []string) (*oauth2.Token, error) {
// This URL is used by the FB JS SDK to get the token from the fragment
redirect := "https://www.facebook.com/connect/login_success.html"
auth := app.Authorization(redirect, permissions, "") + "&response_type=token"
fmt.Printf("Please, open the following URL in your browser:\n%s\n", auth)
fmt.Printf("Then, paste the resulting URL after authorizing the app\nResulting URL: ")
var input string
_, err := fmt.Scanf("%s", &input)
if err != nil {
return nil, err
}
result, err := url.Parse(input)
if err != nil {
return nil, err
}
return oauth2.ParseToken(strings.NewReader(result.Fragment))
}
func (app *App) Extend(token *oauth2.Token) (*oauth2.Token, error) {
requestUrl := fmt.Sprintf("https://graph.facebook.com/oauth/access_token?client_id=%v&client_secret=%v&grant_type=fb_exchange_token&fb_exchange_token=%v",
app.Id, app.Secret, token.Key)
resp, err := app.client().HTTPClient.Get(requestUrl)
if err != nil {
return nil, err
}
defer resp.Close()
if responseHasError(resp) {
return nil, decodeResponseError(resp)
}
newToken, err := oauth2.ParseToken(resp.Body)
if err != nil {
return nil, err
}
if newToken.Expires.IsZero() {
// FB returned the same token because this token
// was previously extended.
newToken.Expires = token.Expires
}
return newToken, nil
}