我已經使用定製版本的類似co獲得db.exec函數，它使用yield來執行數據庫請求。你可以將參數傳遞給一個生成器函數（我傳入一個連接對象 - 請參閱我在其中執行的註釋）。
下面是db.exec功能非常類似於co確實
exec(generator) {
var self = this;
var it;
debug('In db.exec iterator');
return new Promise((accept,reject) => {
debug('In db.exec Promise');
var myConnection;
var onResult = lastPromiseResult => {
debug('In db.exec onResult');
var obj = it.next(lastPromiseResult);
if (!obj.done) {
debug('db.exec Iterator NOT done yet');
obj.value.then(onResult,reject);
} else {
if (myConnection) {
myConnection.release();
debug('db.exec released connection');
}
accept(obj.value);
debug('db.exec Promise Resolved with value %d',obj.value);
}
};
self._connection().then(connection => {
debug('db.exec got a connection');
myConnection = connection;
it = generator(connection); //This passes it into the generator
onResult(); //starts the generator
}).catch(error => {
logger('database', 'Exec Function Error: ' + error.message);
reject(error);
});
});
}
連接對象也是由數據庫連接對象封裝，並提供用於處理從結果的行發電機功能的能力數據庫，但我不會在這裏發佈（雖然下面的例子是使用它來處理行）。
這裏是使用exec函數來運行的SQL
db.exec(function*(connection) {
if (params.name === ADMIN_USER) {
debug('Admin Logon');
user.name = ADMIN_DISPLAY;
user.keys = 'A';
user.uid = 0;
let sql = 'SELECT passwordsalt FROM Admin WHERE AdminID = 0';
connection.request(sql);
yield connection.execSql(function*() {
let row = yield;
if (row) {
user.nopass = (row[0].value === null);
} else {
user.nopass = false;
}
debug('Admin Password bypass ' + user.nopass.toString());
});
} else {
debug('Normal User Logon');
let sql = `SELECT u.UserID,PasswordSalt,DisplayName,AccessKey,l.LogID FROM Users u
LEFT JOIN UserLog l ON u.userID = l.userID AND DATEDIFF(D,l.LogDate,GETDATE()) = 0
WHERE u.UserName = @username`;
let request = connection.request(sql);
request.addParameter('username',db.TYPES.NVarChar,params.name);
let count = yield connection.execSql(function*() {
let row = yield;
if (row) {
user.uid = row[0].value;
user.name = row[2].value;
user.keys = (row[3].value === null) ? '' : row[3].value;
user.nopass = (row[1].value === null) ;
user.lid = (row[4].value === null) ? 0 : row[4].value;
debug('Found User with uid = %d and lid = %d, keys = %s',
user.uid, user.lid, user.keys);
}
});
if (count === 0) {
debug('Not Found User');
// couldn't find name in database
reply(false,false);
return;
}
}
if (!user.nopass) {
debug('Need a Password');
//user has a password so we must check it
passGood = false; //assume false as we go into this
let request = connection.request('CheckPassword');
request.addParameter('UserID',db.TYPES.Int,user.uid);
request.addParameter('password',db.TYPES.VarChar,params.password);
yield connection.callProcedure(function*() {
let row = yield;
if (row) {
//got a valid row means we have a valid password
passGood = true;
}
});
} else {
passGood = true;
}
if (!passGood) {
debug('Not a Good Pasword');
reply(false,true);
} else {
if (user.uid !== 0 && user.lid === 0) {
let sql = `INSERT INTO UserLog(UserID,LogDate,TimeOn,UserName) OUTPUT INSERTED.logID
VALUES(@uid,GETDATE(),GETDATE(),@username)`;
let request = connection.request(sql);
request.addParameter('uid',db.TYPES.Int,user.uid);
request.addParameter('username',db.TYPES.NVarChar,user.name);
yield connection.execSql(function*() {
let row = yield;
if (row) {
user.lid = row[0].value;
debug('Users Log Entry = %d',user.lid);
}
});
}
reply(true,user);
}
})
.catch((err) => {
logger('database','Error on logon: ' + err.message);
reply(false,false);
});
});
的序列的一個例子