问题与模板的多个实例上的订阅 [英] Issue with subscriptions on multiple instances of a template

问题描述

这是场景。我有一个包含#each循环的模板，并呈现特定模板的实例，并根据文档设置每个模板上的数据上下文。

 < template name ='live'> 
< div class ='row'> 
 {{#each runways}} 
< div class ='col-md-2'> 
 {{> runway_panel}} 
< / div> 
 {{/ each}} 
< / div> 
 
< / template> 
  

这是帮助者支持它：

< pre $ Template.live.helpers（{
runways：function（）{
return Runway_Data.find（）;
}
}） ;


这有效，我的问题如下。每个live_event_log实例都有一个模板级订阅，订阅了一个采用数据上下文的_id参数的发布，如下所示：

  Template.runway_panel.onCreated（function（）{
 var instance = this; 
 instance.autorun（function（）{
 var subscription = instance.subscribe（'runway_status'，this.data。 _id）; 
}）; 
 
 instance.status = function（）{
 return Runway_Status.find（）; 
} 
 
 }）; 
  

这是刊物：

<$ p $ （runway）{

if（this.userId）{
//检索给定的最后一个已知状态跑道

返回Runway_Status.find（{跑道：跑道}）;
}

}）;

这是当它全部崩溃时，我在浏览器控制台上得到这个：

  [日志]排队任务异常：http：// localhost：3000 / client / views / live / runway_panel.js？4efaac87b39527d3dfd3d65a174520f9bce3c565：4：73 （meteor.js，第888行）_withTemplateInstanceFunc @ http：// localhost：3000 / packages / blaze.js？a5c324925e5f6e800a4c618d71caf2848b53bf51：3476：16 
 http：// localhost：3000 / packages / blaze.js？a5c324925e5f6e800a4c618d71caf2848b53bf51：1864 ：54 
 _withCurrentView @ http：// localhost：3000 / packages / blaze.js？a5c324925e5f6e800a4c618d71caf2848b53bf51：2197：16 
  

只要我将订阅行注释掉其他所有工作，我是否在这里错过了一些非常明显的内容？它可能与多个订阅到同一刊物有关吗？

谢谢！ ：）

解决方案

感谢Jeremy S.输入和一些睡眠后我终于在没有自动运行的情况下找到了一个夜班。所以这里是为后人：

  Template.runway_panel.onCreated（function（）{
 var self = this; 
 self.subscribe（'runway_status'，this.data._id）; 
}）; 
  

this.data._id ，它现在被限制在最内层的函数中。你想要 instance.data._id （这是非反应性的，所以你不需要 autorun ）或者 Template.currentData（）（它是被动的）。

  Template.runway_panel.onCreated （function（）{
 var instance = this; 
 instance.autorun（function（）{
 var data = Template.currentData（）; 
 var subscription = instance.subscribe（ 'runway_status'，data._id）; 
}）; 
}）; 
  

另请注意，在您的出版物中，您应该将其标记为 this.ready （） if this.userId 是 undefined 。但这不是错误的根源。

Here is the scenario. I have a template that contains a #each loop and renders an instance of a particular template, setting the data context on each template as per the docs.

<template name = 'live'>
<div class = 'row'>
    {{#each runways}}
        <div class = 'col-md-2'>
            {{> runway_panel}}
        </div>
    {{/each}}
</div>

</template>

And this is the helper backing it:

Template.live.helpers({
    runways: function(){
        return Runway_Data.find();
    }
});

This works, my issue is as follows. Each live_event_log instance has a template level subscription that subscribes to a publication that takes the _id parameter of the data context, like so:

Template.runway_panel.onCreated(function(){
    var instance = this;
    instance.autorun(function(){
        var subscription = instance.subscribe('runway_status', this.data._id);
    });

    instance.status = function(){
        return Runway_Status.find();
    }

});

This is the publication:

Meteor.publish('runway_status', function(runway){ 

    if(this.userId){
        //Retrieve the last know status for the given runway

        return Runway_Status.find({runway: runway});  
    }

});

This is when it all falls apart, I get this on the browser console:

 [Log] Exception in queued task: http://localhost:3000/client/views/live/runway_panel.js?4efaac87b39527d3dfd3d65a174520f9bce3c565:4:73 (meteor.js, line 888)_withTemplateInstanceFunc@http://localhost:3000/packages/blaze.js?a5c324925e5f6e800a4c618d71caf2848b53bf51:3476:16
http://localhost:3000/packages/blaze.js?a5c324925e5f6e800a4c618d71caf2848b53bf51:1864:54
_withCurrentView@http://localhost:3000/packages/blaze.js?a5c324925e5f6e800a4c618d71caf2848b53bf51:2197:16

As soon as I comment out the subscription line everything else works, am I missing something really obvious here? Could it have something to do with multiple subscriptions to the same publication?

Thank you! :)

SOLUTION

Thanks to Jeremy S. input and some sleep after a night shift i've finally figured it out without an autorun. So here it goes for posterity:

Template.runway_panel.onCreated(function(){
    var self = this;
    self.subscribe('runway_status', this.data._id);
});

Should probably have tried getting some sleep before trying again!

解决方案

The problem is with this.data._id in your subscription, which right now is scoped to the innermost function. You want instance.data._id (which is nonreactive so you wouldn't need an autorun) or Template.currentData() (which is reactive).

Template.runway_panel.onCreated(function(){
    var instance = this;
    instance.autorun(function(){
        var data = Template.currentData();
        var subscription = instance.subscribe('runway_status', data._id);
    });
});

Also note that in your publication, you should mark it as this.ready() if this.userId is undefined. But that's not the source of the error.

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