调用 Meteor 方法时如何使用回调？

Question

我注意到尽管服务器方法运行良好，但回调函数从未被执行。同样从 Meteor 文档中，我了解到，当 Meteor.Error 被抛出时，它会通知客户端，但我看不到它也能正常工作。我做错了什么？

客户

    if (Meteor.isCordova) {
 getContacts(function (contacts) {
            $meteor.call('createContacts', contacts, function(err){
               alert("in create contacts callback");
                if(err && err.error === "not-logged-in"){
                   alert("error due to not-logged-in");
                    $ionicPopup.alert({
                        title: err.reason || "User not logged in",
                        template: 'Please try again after logged in',
                        okType: 'button-positive button-clear'
                    });
                }
                else if(err && err.error === "contacts-exists"){
                    $ionicPopup.alert({
                        title: err.reason || "Connections already exists",
                        template: 'Please try again after logged in',
                        okType: 'button-positive button-clear'
                    });
                }
                $meteor.call('createConnections');
            });
});

}

function getContacts(success, error) {
    function onSuccess(contacts) {
        success && success(contacts);
    };

    var options = {};
    options.multiple = true;
    var fields = ["displayName", "name"];
    navigator.contacts.find(fields, onSuccess, error, options);

}

服务器

createContacts: function (contacts, callback) {
    if (!this.userId) {
        throw new Meteor.Error('not-logged-in',
            'Must be logged in to  update contacts')
    }
    var userId = this.userId, exist = Contacts.findOne({userId: userId});
    log.debug("Is contacts for userId %s exist in database ? %s", userId, !! exist);
    if (!exist) {
        Contacts.insert({'userId': userId, 'contacts': contacts}, function () {
            callback && callback();
        });
    } else {
        log.debug("Contacts for user exists so throwing exception as contacts-exists");
        var meteorErr =  new Meteor.Error('contacts-exists', "Contacts are already exist");
        callback && callback(meteorErr);
    }


},

Answer 1

这些回调是异步的。您的服务器端方法不应该调用回调函数，甚至也不应该期望一个作为参数。

将回调作为最后一个参数传递给Meteor.call('createContacts') 是正确的，但由createContacts 的接收者决定何时调用该回调。简单来说，从客户端的角度来看，服务器的工作就是返回一个“OK”或“错误”信号。

删除方法定义（在服务器上）中对回调的任何引用，并期望客户端在服务器响应时执行该回调。

试试这个：

服务器

createContacts: function (contacts) {
    if (!this.userId) {
        throw new Meteor.Error('not-logged-in',
            'Must be logged in to  update contacts');
    }
    var userId = this.userId;
    var exist = Contacts.findOne({userId: userId});
    log.debug("Is contacts for userId %s exist in database ? %s", userId, !! exist);
    if (!exist) {
        Contacts.insert({'userId': userId, 'contacts': contacts});
    } else {
        log.debug("Contacts for user exists so throwing exception as contacts-exists");
        throw new Meteor.Error('contacts-exists', "Contacts are already exist");
    }
},

客户

   $meteor.call('createContacts', contacts, function(err){
       alert("in create contacts callback");
        if(err && err.error === "not-logged-in"){
           alert("error due to not-logged-in");
            $ionicPopup.alert({
                title: err.reason || "User not logged in",
                template: 'Please try again after logged in',
                okType: 'button-positive button-clear'
            });
        }
        else if(err && err.error === "contacts-exists"){
            $ionicPopup.alert({
                title: err.reason || "Connections already exists",
                template: 'Please try again after logged in',
                okType: 'button-positive button-clear'
            });
        }
        $meteor.call('createConnections');
    });

Answer 2

似乎我需要使用.then() 中记录的Angular-Meteor Document

还按照amageddian修改了代码