Returning value from callback within Meteor.method

Question

I am running into something I don\'t understand with Meteor. I have this method, which takes a query, sends it to amazon, and then in the callback of that function I try to

Answer 1

For anyone new to Meteor seeing this question and wondering why a library like Future or Fiber is necessary, it's because that call to amazon.execute is asynchronous.

In Javascript, many operations that take an extended period of time don't run one line after the next; Examples like writing to a database, using window.setTimeout, or making HTTP requests. With methods like these, historically you've needed to wrap the code you want to run after the fact in a callback.

Future and Fibers provide syntactic sugar and additional functionality, but their core functionality is the same.

Meteor uses special behind-the-scenes tricks to make certain built-in operations (like accessing MongoDB) appear synchronous, while still taking advantage of the increased performance of asynchronous code. For this reason, you normally only have to worry about async when using external packages (like the Amazon one in this example).

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Here's a fully fleshed-out example of using both Future and Fibers:

There are some great articles explaining the nature of Sync/Async in Meteor on the Discover Meteor blog and at the Meteor Chef