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异步/等待函数的执行顺序不正确

sequelize.js twilio async-await promise node.js

sigil · 技术社区 · 6 年前

await

我的主要代码是:

app.post('/sms',async function(req,res){
    try{
        worker=await worker.updateWorker('+18005559999',process.env.TWILIO_OFFLINE_SID);
        responseValue="/sms: worker "+worker.friendlyName+" updated to: "+worker.activityName;
        console.log(responseValue);
        res.status(200).send();

    }
    catch(err){
        console.log("/sms error: "+err);
    }
}

worker.updateWorker()

async updateWorker(contact_uri,activitySid){
        console.log("updateWorker: getting workerSid from database");
        workerSid=await database.getWorkerSid(contact_uri);
        console.log("updateWorker: workerSid is "+workerSid);
        worker=await this.updateWorkerFromSid(workerSid,activitySid);
        console.log("updateWorker: worker's friendlyName is "+worker.friendlyName);
        return worker;
    }

database.getWorkerSid() 是:

getWorkerSid(contact_uri){
        return new Promise(function(resolve,reject){
            sequelize.query("select * from worker where contact_uri='"+contact_uri+"'",
            { type: sequelize.QueryTypes.SELECT})
            .then(result=>{
                if(result.length==0){
                    resolve(null);
                }
                else{
                    resolve(result[0].sid);
                }
            })
            .catch(err=>reject(err));
        });
    }

this.updateWorkerFromSid()

async updateWorkerFromSid(workerSid,activitySid){
        var worker;
        try{
            worker=await this.workspace.workers(workerSid)
                        .update({
                            activitySid:activitySid
                        });
            console.log("updateWorkerFromSid: worker has been updated to activity: "+worker.activityName);
            return worker;
        }
        catch(err){
            console.log("updateWorkerFromSid error: "+err);
        }
        finally{
            return worker;
        }

    }

updateWorker: getting workerSid from database
Executing (default): select * from worker where contact_uri='+18005559999'
/sms error: ReferenceError: workerSid is not defined

sequelize.query() 请来 database.getWorkerSid() ,但执行过程将继续进行,而无需等待查询承诺得到解决,并在线:

console.log("updateWorker: workerSid is "+workerSid);

这个 workerSid 未定义,因此会发生崩溃,错误会传播回主代码中的try/catch块。

基本上,我想做的是:

收到 工人阶级 contact_uri
使用 工人阶级

如何设置async/await以确保事件按此顺序发生?

1 回复 | 直到 6 年前

sigil 6 年前

我重构了 database.getWorkerSid() ,以摆脱Promise构造函数反模式,如下所示:

async getWorkerSid(contact_uri){
        var workerRow=await this.getRowFromWorkerTable(contact_uri);
        if (workerRow.length==0){
            return null;
        }
        else{
            return workerRow[0].sid;
        }
    }

getRowFromWorkerTable(contact_uri){
        return sequelize.query("select * from worker where contact_uri='"+contact_uri+"'",
        { type: sequelize.QueryTypes.SELECT});
    }

我用 var ,例如。

var workerSid=await database.getWorkerSid(contact_uri);

现在可以了。