感觉async无法解决的异步改写

问答

Iitbasketplayer发布于11 年前最后回复11 年前|5 回复4361 浏览0 收藏

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]);
                        });
                    });
                }
            });

        });

    }));

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20082496#1·11 年前

第一个成功就返回错误，错误里面包含你需要的data

haozxuan#2·11 年前

这个有什么难的？

itbasketplayer#3·11 年前

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]); }); }] }); });

hezedu#4·11 年前

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]);

itbasketplayer#5·11 年前

666，不过sas是什么，也是一个异步框架？

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感觉async无法解决的异步改写

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