node.js - promise 未按正确顺序运行

Question

以下按顺序登录:here1 here2 here5 here3 here4。虽然，here5 应该是最后一个，它根本不会到达 here6。我怎样才能让 here1 到 here6 都按顺序正常运行？我正在使用 Sailsjs 和 Bluebird 。

//manually wrapping a callback API like Kaiseki
function createKaisekiObject(className, job) {
    console.log('here2');
    return new Promise(function(resolve, reject) {
        kaiseki.createObject(className, job, function(err, res, body, success) {
            //resolve or reject the promise
            if (err) {
                reject(err);
                return;
            }
            console.log('here3');
            resolve(body);
        });
    });
}

function saveJob(body) {
    console.log('here4', body);

    return Jobs.create({
        owner: req.user.id,
        jobId: body.objectId
    });
}

function sendResponse(req, res) {
    console.log('here5');

    return function(savedJob) {
        console.log('here6', savedJob, req, res);

        // res.json({
        //  success: true,
        //  message: "Running analysis on game",
        //  jobId: savedJob.jobId
        // });
        //return the job
        return savedJob;
    };
}

module.exports.index = function(req, res) {
    console.log('here1');
    var jobId = uuid.v4();
    var job = {
        owner: req.user.id,
        numOfGames: 1,
        numOfGamesCompleted: 0
    };
    var className = 'jobs';
    //promise
    var createJob = createKaisekiObject(className, job)
    .then(saveJob)
    .then(sendResponse(req, res));

    //when first step is done, do more stuff...
    createJob.then(function(savedJob) {
        //do more stuff here...
        console.log('here6');
    });


};

Answer 1

首先，我不相信 Jobs.create 会返回一个 promise ，因此如果您想继续链接，则需要将其包装在一个 promise 中。

function saveJob(body) {
    console.log('here4', body);

    return function(body) {
        return new Promise(function(resolve, reject) {
            Jobs.create({
                owner: req.user.id,
                jobId: body.objectId
            }).exec(function(err, job) {
                resolve(job);
            });
        });
    };
}

接下来确保 sendResponse 返回的函数也返回一个 promise ，因为返回的函数将在链接的 then block 中执行。

function sendResponse(req, res) {
    console.log('here5');

    return function(savedJob) {
        return new Promise(function(resolve, reject) {
            console.log('here6', savedJob, req, res);
            res.json({
                success: true,
                message: "Running analysis on game",
                jobId: savedJob.jobId
            });
            //return the job
            resolve(savedJob);
        });
    };
}