我想要把mysqldb的3个查询用async做优化，有个难点，就是如果第一个查询存在数据，后面2个就不执行，并return结果！用auto和waterfall都没有成功！求指教！ function(req, username, password, done) { //md5加密 password = md5(password); // asynchronous // User.findOne wont fire unless data is sent back process.nextTick(function() {
var findUserByUnPwSql = "select * from user where username = '" + username + "'and password ='" + password + "'";
mysqldb.excute(findUserByUnPwSql, function (results) {
if(results.length>0){
return done(null, false, req.flash('signupMessage', '该用户已存在！'));
}else{
var insertUserSql = "insert into user(username,password) values('" + username + "','" + password + "')";
mysqldb.excute(insertUserSql, function (results) {
mysqldb.excute(findUserByUnPwSql, function (results) {
return done(null, results[0]);
});
});
}
});
});
}));我写出来了，其实想多了，结果直接return就可以，不用考虑怎么怎么存结果集。不过要注意的是，return的时候，要保证async不要再往下执行了，即callback(err);
process.nextTick(function() { async.auto({ findUserByUnPwFunc: function (callback) { var findUserByUnPwSql = “select * from user where username = '” + username + “’and password =’” + password + "’"; mysqldb.excute(findUserByUnPwSql, function (results) { callback(null, results); }); }, insertUserFunc: ['findUserByUnPwFunc’, function (callback, results) { var result = results.findUserByUnPwFunc; if (result.length > 0) { callback(“exist user cannot regist!”); return done(null, false, req.flash(‘signupMessage’, ‘该用户已存在！’)); } else { var insertUserSql = “insert into user(username,password) values('” + username + “’,’” + password + "’)"; mysqldb.excute(insertUserSql, function (results) { callback(null, true); }); } }], findUserByUnPwAfterFunc: ['findUserByUnPwFunc’, 'insertUserFunc’, function (callback, results) { console.log(results.insertUserFunc); var findUserByUnPwSql = “select * from user where username = '” + username + “’and password =’” + password + "’"; mysqldb.excute(findUserByUnPwSql, function (results) { callback(null, true); return done(null, results[0]); }); }] }); });
按你逻辑用sas实现了下
var sas = require('sas');
var findUserByUnPwSql = "select * from user where username = '" + username + "'and password ='" + password + "'";
var find_task = function (cb){
mysqldb.excute(findUserByUnPwSql, function (results) {
if(results.length>0){
done(null, false, req.flash('signupMessage', '该用户已存在！'));
cb('$END');
}else{
done(null, results[0]);
cb();
}
});
}
var insert_task = function(cb){
mysqldb.excute(insertUserSql, function (results) {
cb();
});
}
sas([find_task,insert_task,find_task]);
