node.js Mongoose pre.save() 异步中间件未按预期工作
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Mongoose pre.save() async middleware not working as expected
提问by Olivier
Following up from : Mongoose unique validation error type
跟进：猫鼬唯一验证错误类型
I'm using this schema with mongoose 3.0.3from npm:
我正在使用mongoose 3.0.3来自 npm 的这个架构：
var schema = new Schema({
_id: Schema.ObjectId,
email: {type: String, required: true, unique: true}
});
With this middleware to get a validationError from unique:true
使用此中间件从 unique:true 获取验证错误
schema.pre("save", function(next, done) {
var self = this;
model.findOne({email : this.email}, 'email', function(err, results) {
if(err) {
done(err);
} else if(results) {
console.warn('results', results);
self.invalidate("email", "email must be unique");
done(new Error("email must be unique"));
} else {
done();
}
});
next();
});
However, it does not work!
但是，它不起作用！
Users.create()will still return a a MongoError: E11000 duplicate key error indexand the console.warn()is only called after that.
Users.create()仍将返回 aaMongoError: E11000 duplicate key error index并且console.warn()仅在此之后调用。
The save action should not be called until all middleware done()have been called according to the docs, and I should get back a validation error.
在done()根据文档调用所有中间件之前，不应调用保存操作，并且我应该返回验证错误。
It looks like the done()behavior is not working as expected,
看起来done()行为没有按预期工作，
Any idea why?
知道为什么吗？
回答by JohnnyHK
You're using a parallel middleware callback function (with both nextand done), but you're not setting the parallel flag in the schema.preparameters so it's using the serial rules.
您正在使用并行中间件回调函数（同时带有next和done），但您没有在schema.pre参数中设置并行标志，因此它使用串行规则。
So either include the parallel flag in your call:
因此，要么在您的调用中包含并行标志：
schema.pre("save", true, function(next, done) { ...
Or switch to a serial middleware callback style if that's all you need anyway:
或者切换到串行中间件回调风格，如果这就是你所需要的：
schema.pre("save", function(next) {
var self = this;
model.findOne({email : this.email}, 'email', function(err, results) {
if(err) {
next(err);
} else if(results) {
console.warn('results', results);
self.invalidate("email", "email must be unique");
next(new Error("email must be unique"));
} else {
next();
}
});
});
