如何从服务器上设置的文件范围变量在客户端读取数据？

Question

I'm new to meteor (and javascript) and trying to make a simple app that will read some data from an web api and create a chart.

The data that I retrieve doesn't need to be stored in a database. My naive approach consists of creating a variable with file scope to store the data, making an http request on the server upon startup and then reading the data from the variable on the client to create a chart using d3.js. Later I will add code to retrieve the data at a specified interval, but I just want to figure out how to pass the data from the server to the client.

Here's the relevant portions of the js file...

var dayData = "";

if (Meteor.isServer) {
  Meteor.startup(function () {
    dayData = HTTP.call("GET",
             "http://finance.yahoo.com/d/quotes.csv?s=AAPL+GOOG&f=nb2b3");
    console.log(dayData.content); // check to see data exists 
  });
} 


if (Meteor.isClient) {
  Template.hello.rendered = function () {
    var self = this;

    if (! self.handle) {
      self.handle = Deps.autorun(function () {

        d3.csv.parse(dayData.content, function(data) {
          d3.select("#example")
              .datum(data)
              .call(chart);
        });  
      });
    }
 };

Within the client portion of the code, the dayData is set to "" and not the contents of the result object that I have printed to the terminal on the server side code.

My first question is why doesn't the dayData variable contain the result object from the http request when reading it on the client? My second question is what is a best practice for reading remote data on the server and accessing that data on the client in some way that doesn't require using a database?

Answer 1

1) On the client, the variable Meteor.isServer is false , so the if block is not executed, so the HTTP call does not happen and the variable is not initialized.

2) Use a method:

var dayData;

...

if(Meteor.isServer) {
  Meteor.methods({
    getDayData: function() {
      return dayData;
    },
  });
}


if(Meteor.isClient) {
  Meteor.startup(function() {
    Meteor.call('getDayData', function(error, result) {
      dayData = result;
    });
  });  
}