/// <summary>
/// 询问服务器，文件是否存在
/// </summary>
/// <param name="fileId">要询问的文件信息</param>
/// <param name="success">成功回调函数</param>
/// <param name="failure">失败回调函数</param>
/// <returns>文件是否已经存在</returns>
public static void IsFileExistInServer(string fileId, Success <bool> success, Failure failure = null)
{
var restTemplate = new RestTemplate();
restTemplate.MessageConverters.Add(new NJsonHttpMessageConverter());
restTemplate.HeadForHeadersAsync(Resources.fileInfoUrl + "/" + fileId, resp =>
{
if (resp.Error != null)
{
failure?.Invoke(resp.Error.Message);
}
else
{
var singleValue = resp.Response.GetSingleValue("isExist");
success?.Invoke(!string.IsNullOrWhiteSpace(singleValue) && singleValue.ToUpper().Equals("TRUE"));
}
});
}