Problems with using mongoose in Koa

Reprinted Please note:Theviper http://www.cnblogs.com/TheViper

Let's take a look at the following example.

This. login = function *(){
....... VaR q = usermodel. findone ({Email: name, PWD: Pwd}); q. select ('_ id'); q.exe C (function (ERR, ID) {If (ERR) return handleerror (ERR); this. body = ID ;});}

This is an Ajax login, but the response will return not found.

The crux of the problem is that no response is returned. Why is no response returned?

This is also quite easy to understand. Because the retrieval in q.execute is not implemented by this.body.specifically, mongoose's query q.exe C is an asynchronous operation, while the other side of KOA runs directly in the generator middleware mode regardless of whether the asynchronous operation is complete.

The solution is simple, that is, to convert the mongoose query to the generator middleware of KOA and add it to Koa, so Koa will not ignore the existence of the mongoose query.

You can rewrite q.exe C to the thunk format.

Function execquery (query) {return function (FN) {query.exe C (function (ERR, Res) {If (ERR) return FN (ERR); FN (null, res );});}}

Q = usermodel. findone ({Email: name, PWD: Pwd}); q. Select ('_ id'); this. Body = yield execquery (Q );

 

Problems with using mongoose in Koa