Return the userinfo
<boost/url/authority_view.hpp>
template<string_token::StringToken StringToken = string_token::return_string>
StringToken::result_type
userinfo(StringToken&& token) const;
If present, this function returns a string representing the userinfo (which may be empty). Otherwise it returns an empty string. Any percent-escapes in the string are decoded first.
assert( url_view( "http://jane%2Ddoe:pass@example.com" ).userinfo() == "jane-doe:pass" );
Linear in this->userinfo().size().
Calls to allocate may throw.
userinfo    = user [ ":" [ password ] ]
authority   = [ userinfo "@" ] host [ ":" port ]
| Name | Description | 
|---|---|
| token | A string token to receive the result. | 
has_password, has_userinfo, encoded_password, encoded_user, encoded_userinfo, password, user.