public async Task <User> LogInAsync(User user)
{
User loggedUser = (await database.SelectAsync <User, User>(u => u.UserName == user.UserName)).FirstOrDefault();
if (loggedUser == null || !loggedUser.Password.Equals(await encrypt.HashEncryptAsync(user.Password ?? throw new NullReferenceException("密码为空"), Convert.FromBase64String(loggedUser.Salt))))
{
throw new Exception("用户名或密码错误");
}
return(loggedUser);
}
public IObservable <ISBNInfoGetDataPackage> GetISBNInfo(IObservable <ISBNInfoGetDataPackage> getStream)
{
// 先查询一遍数据库
IObservable <ISBNInfoGetDataPackage> databaseResult = getStream
.Where(isbnGet => !string.IsNullOrWhiteSpace(isbnGet.ISBN))
.Select(isbnGet =>
Observable.FromAsync(async() =>
{
try
{
isbnGet.ISBNInfo = (await database.SelectAsync <ISBNInfo, ISBNInfo>(isbn => isbn.ISBN == isbnGet.ISBN)).FirstOrDefault();
}
catch (Exception ex)
{
isbnGet.Exceptions.Add(ex);
}
return(isbnGet);
})
).Merge();
// 把查到的筛选出来打包成最终结果的一部分
IObservable <ISBNInfoGetDataPackage> getDbResult = databaseResult
.Where(isbnGet => isbnGet.ISBNInfo != null);
// 把查不到的拿去用API查
IObservable <ISBNInfoGetDataPackage> httpResult = httpISBNInfo.GetISBNInfo(databaseResult
.Where(isbnGet => isbnGet.ISBNInfo == null));
// 把两次都查不到的筛选出来打包成最终结果的一部分
IObservable <ISBNInfoGetDataPackage> getBadResult = httpResult
.Where(isbnGet => isbnGet.ISBNInfo == null);
// 把API查到的筛选出来存一遍数据库, 再打包成最终结果的一部分
IObservable <ISBNInfoGetDataPackage> getHTTPResult = httpResult
.Where(isbnGet => isbnGet.ISBNInfo != null)
.Select(isbnGet =>
Observable.FromAsync(async() =>
{
try
{
await database.InsertAsync(new ISBNInfo[] { isbnGet.ISBNInfo });
}
catch (Exception ex)
{
isbnGet.Exceptions.Add(ex);
}
return(isbnGet);
})
).Merge();
return(Observable.Merge(getDbResult, getBadResult, getHTTPResult)); // 合并全部结果
}
public async Task <List <Book> > QueryAsync(Expression <Func <Book, bool> > whereExp = null, int pageIndex = 0, int pageSize = 0)
{
return(await database.SelectAsync <Book, Book>(whereExp, pageIndex : pageIndex, pageSize : pageSize));
}
public async Task <BorrowLog> BorrowBookAsync(User userId, Book bookId)
{
BorrowLog leaseLog = null;
Book bCheck = (await database.SelectAsync <Book, Book>(b => b.Id == bookId.Id)).FirstOrDefault();
User uCheck = (await database.SelectAsync <User, User>(u => u.Id == userId.Id)).FirstOrDefault();
_ = (await database.SelectAsync <BorrowLog, BorrowLog>(null, pageIndex: 1, pageSize: 1)).FirstOrDefault();
if (bCheck == null || uCheck == null)
{
throw new Exception("借阅人或目标不合法");
}
using IDatabaseTransactionManager transaction = database.StartTransaction();
try
{
await database.ForUpdateAsync <Book, Book>(b => b.Id == bookId.Id, transaction : transaction.GetTransaction());
Book bSnap = (await database.SelectAsync <Book, Book>(b => b.Id == bookId.Id, transaction: transaction.GetTransaction())).FirstOrDefault();
if (bSnap == null)
{
throw new Exception("借阅目标不合法");
}
if (bSnap.Margin <= 0)
{
throw new Exception("借阅目标数量不足");
}
User uSnap = (await database.SelectAsync <User, User>(u => u.Id == userId.Id, transaction: transaction.GetTransaction())).FirstOrDefault();
if (uSnap == null)
{
throw new Exception("借阅人不合法");
}
List <BorrowLog> leaseLogs = await database.SelectAsync <BorrowLog, BorrowLog>(bl => bl.BookId == bookId.Id && bl.UserId == userId.Id && bl.GiveBack == null, transaction : transaction.GetTransaction());
if (leaseLogs.Count > 0)
{
throw new Exception("已有未归还的同名同书借阅记录");
}
int accreditedDays = credit.GetAccreditedDays(uSnap);
if (accreditedDays == 0)
{
throw new Exception("借阅人信誉过低");
}
if (await database.UpdateAsync <Book, int>(book => book.Margin - 1, book => book.Id == bSnap.Id, transaction: transaction.GetTransaction()) == 0)
{
throw new Exception("更新书本库存失败");
}
leaseLog = new BorrowLog {
BookId = bSnap.Id, UserId = uSnap.Id, Deadline = DateTime.Today.AddDays(accreditedDays)
};
if (await database.InsertAsync(new BorrowLog[] { leaseLog }, transaction: transaction.GetTransaction()) == 0)
{
throw new Exception("创建借阅记录失败");
}
transaction.Commit();
}
catch (Exception)
{
transaction.Rollback();
throw;
}
return(leaseLog);
}