所以..我最难学习如何承诺。
我正在使用bluebird
(https://github.com/petkaantonov/bluebird),正如我所建议的那样——为了驯服我的回调地狱。例子:
function login(req,res,con,mysql,P) {
var ref = undefined;
con.getConnection(function(err,connection) {
if (err) console.log("Get Connection Error.. "+err);
con.query('SELECT password,id FROM player WHERE name='+mysql.escape(req.body.user),function(err,rows,fields) {
if (err) throw err;
if (!rows[0]) {
res.send({
"msg":"Your username and or password was incorrect.",
"flag":true,
"title":": Login Failed"
});
}
if (rows[0].password !== "undefined") {
if (hash.verify(req.body.pass,rows[0].password)) {
req.session.loggedIn = true;
req.session.user = rows[0].id;
ref = new P(rows[0].id,con,req);
res.send({
"msg":"You have logged in!",
"flag":false,
"title":": Logged In"
});
} else {
res.send({
"msg":"Your username and or password was incorrect.",
"flag":true,
"title":": Login Failed"
});
}
}
});
connection.release();
});
console.log(ref);
return ref;
}
很恶心,到处都是回调,而且函数ref
在查询回调执行完之前就返回了。
解决方案:承诺!
我尝试使用快速入门转换我的功能.. 所以我在创建连接之前promisefyAll
我的mysql
模块:
var mysql = require("mysql");
var Promise = require("bluebird");
Promise.promisifyAll(mysql);
我写了我的函数如下:
function login(req,res,con,mysql,P) {
var ref = undefined;
Promise.promisify(con.getConnection)().then(function(connection) { //updated line returns error no method promisify. Bluebird v. 1.1.1
con.query('SELECT password,id FROM player WHERE name='+mysql.escape(req.body.user)).then(function(rows,fields) {
if (hash.verify(req.body.pass,rows[0].password)) {
req.session.loggedIn = true;
req.session.user = rows[0].id;
ref = new P(rows[0].id,con,req);
res.send({
"msg":"You have logged in!",
"flag":false,
"title":": Logged In"
});
} else {
res.send({
"msg":"Your username and or password was incorrect.",
"flag":true,
"title":": Login Failed"
});
}
});
return ref;
});
}
但我不断得到TypeError: Cannot call method 'then' of undefined at Object.login (/var/www/post/posts.js:36:22)
和
TypeError: undefined is not a function at Pool.<anonymous> (/var/www/node_modules/mysql/lib/Pool.js:53:14)
错误。有人可以帮助我了解如何实现查询我的数据库的承诺(正确)吗?
编辑(接受回答后:):这是我调用登录功能的方式:
app.post("/login",function(req,res) {
Player = post.login(req,res,con,mysql,p);
console.log(Player); // logs [Object object]
}); //inside the login function, it logs the object like it should