/// <summary>
///根据url生成短链接id
/// </summary>
/// <param name="url"></param>
/// <returns></returns>
public string Generate(string url)
{
var errorCount = 0;
var postfix = string.Empty;
var shortId = string.Empty;
ShortUrlMap shortUrlMap = null;
// 违反唯一索引异常
Func <DbUpdateException, bool> duplicateKeyPredict = ex =>
ex.InnerException != null &&
ex.InnerException.Message.Contains("duplicate key");
Policy.Handle <DbUpdateException>(duplicateKeyPredict).Retry(2).Execute(() =>
{
// 在违反唯一索引的情况下，判断是否真实的重复提交
if (errorCount == 1 && _storeService.Exist(shortId, url))
{
shortUrlMap = new ShortUrlMap {
ShortId = shortId, LongUrl = url
};
return;
}
// hash冲突
else
{
// 计数错误次数
errorCount++;
// 追加自定义后缀(首次不需要追加，所以为空)
url += postfix;
// 首次完成后，开始追加真正的后缀
if (string.IsNullOrWhiteSpace(postfix))
{
postfix = GlobalConfig.CONFLICT_POSTFIX;
}
shortId = _shortIdService.Generate(url);
shortUrlMap = new ShortUrlMap {
ShortId = shortId, LongUrl = url
};
_storeService.Add(shortUrlMap);
}
});
return(shortUrlMap.ShortId);
}
/// <summary>
/// 增加短长链接映射
/// </summary>
/// <param name="shortUrlMap"></param>
public void Add(ShortUrlMap shortUrlMap)
{
//if (Exist(shortUrlMap.ShortId, shortUrlMap.LongUrl)) throw new UniqueException();
_context.ShortUrlMaps.Add(shortUrlMap);
_context.SaveChanges();
}
