Question

我有一个执行查询的promise链，检查结果，如果我找到了我需要的东西，则调用response.success（），如果没有，它会移动到下一个查询...由于某种原因，但是当我调用response.success（）来执行下一个promise。没有response.success（）结束函数吗？

此代码实质上检查我的每个角色，以查看请求用户所属的角色。

当我调用response.success（）时，如何停止promise链？

Parse.Cloud.define('getUserRole', function (request, response) {

    Parse.Cloud.useMasterKey();

    const NAME = "name";
    const USER = "user";
    const USERNAME = "username";
    const CUSTOMER_ROLE = "Customer";
    const BARBER_ROLE = "Barber";
    const ADMIN_ROLE = "Admin";

    var user = request[USER];
    if (user == null){
        console.log("@Null Check for user");
        response.success(CUSTOMER_ROLE);
        return;
    } else {
        console.log("Username: " + user.get(USERNAME));
    }

    //Query customers first because that is the most likely role for most cases
    var customerRoleQuery = new Parse.Query(Parse.Role);
    customerRoleQuery.equalTo(NAME, CUSTOMER_ROLE);
    customerRoleQuery.first().then(function (role) {
        console.log("@query customer Role: " + JSON.stringify(role));

        //Customer Role

        var customerQuery = role.getUsers().query();
        customerQuery.equalTo(USERNAME, user.get(USERNAME));
        return customerQuery.first();

    }).then(function (user) {
        console.log("@query for customer users: " + JSON.stringify(user));

        //Check if we found the user in the customer role

        if (user){
            console.log("@ customer user");
            //We found the user in the customer role
            response.success(CUSTOMER_ROLE);
        } else {
            console.log("@ barber role query");
            //We didn't find the user in the customer role, get the barber role.
            var barberRoleQuery = new Parse.Query(Parse.Role);
            barberRoleQuery.equalTo(NAME, BARBER_ROLE);
            return barberRoleQuery.first();
        }

    }).then(function (role) {
        console.log("@query Barber Role: " + JSON.stringify(role));

        //Barber Role

        var barberQuery = role.getUsers().query();
        barberQuery.equalTo(USERNAME, user.get(USERNAME));
        return barberQuery.first();

    }).then(function (user) {
        console.log("@query for barber users: " + JSON.stringify(user));

        //Check if we found the user in the barber role

        if (user){
            //We found the user in the barber role
            response.success(BARBER_ROLE);
        } else {
            //We didn't find the user in the barber role, get the admin role
            //This may seem unnecessary, but we can't assume if we didn't find them in the customer or barber roles they are admins. That is a security risk.
            var adminRoleQuery = new Parse.Query(Parse.Role);
            adminRoleQuery.equalTo(NAME, ADMIN_ROLE);
            return adminRoleQuery.first();
        }

    }).then(function (role) {
        console.log("@query Admin Role: " + JSON.stringify(role));

        //Admin Role

        var adminQuery = role.getUsers().query();
        adminQuery.equalTo(USERNAME, user.get(USERNAME));
        return adminQuery.first();

    }).then(function (user) {
        console.log("@query admin users: " + JSON.stringify(user));

        //Check if we found the user in the admin role
        if (user){
            //We found the user in the admin role
            response.success(ADMIN_ROLE);
        } else {
            //Still didn't find the user in a role, just assume they are customers
            response.success(CUSTOMER_ROLE);
        }

    }, function(error){
        console.log("@Error");
        response.error(error);
    });

});

Answer 1

response.success()终止任何正在进行的异步调用，但它本身并不终止云代码。我认为发布的代码中发生的是success()被调用，然后当前承诺的then运行（这会影响您的日志，但没有其他内容）。

我们可以做一些事情来更好地组织当前方法下的代码，但最好还是完全改变方法。无需在代码中枚举角色以查看用户具有的角色。考虑一下：

// return a promise that's fulfilled with any Parse.Role which has user in the 'users' relation
function getUserRoles(user) {
    var query = new Parse.Query(Parse.Role);
    query.equalTo('users', user);
    return query.find();
}

为云代码包装也很容易：

Parse.Cloud.define('getUserRole', function(request, response) {
    getUserRoles(request.user).then(function(roles) {
        response.success(roles);
    }, function(error) {
        response.error(error);
    });
});

Javascript / Parse.com - Promises，在promise

1 个答案: