A core concept in Meteor is reactivity. Basically, this means that Meteor can re-run computational functions automatically whenever their (reactive) data sources change. Typically, this happens without your having to think about it, since you’re using an in-built reactive data source, such as database collections. A typical example of a function needing to react to a data source (e.g. a collection) changing is a template helper, which needs to produce a new value to base the template rendering on.

I just ported the Trello client API to a Meteor package, in order to be able to authorize my application before making actual API calls from the server side (let’s just avoid the hassle of cross-site scripting). The following snippet shows my client side flow for creating a Trello board; first I authorize against Trello, then I call a Meteor server method to perform the corresponding Trello REST API call:

I am facing the need to upload pictures to Amazon S3 in my Meteor application, MuzHack. The pictures must be resized before storing in S3, and there’s the option of doing this either on my server or in the client. I have elected to go with the latter for now, since it’s simple and doesn’t put load on my server. To resize pictures client side I am using the Meteor Clientside Image Manipulation library, and to upload pictures to S3 I am using Slingshot.

Today I wrote a Python script in order to insert data into Meteor’s MongoDB instance, and the first question that came up was how to get hold of the connection parameters. It turns out that Meteor has a command for this purpose: meteor mongo -U [site] If you leave out the 'site' argument, you’ll get the URL to connect to the local MongoDB instance for the current Meteor app (relative to the directory you’re in).

In my Meteor-based project MusitechHub, I recently had to figure out how to set page title dynamically for certain pages. I’m using Iron Router to implement routing in the application, which laid the premise for the solution. I gathered from the #meteor channel on IRC that I could base my solution on Manuel Schoebel’s SEO package, which is able to set the current page title. Since I wasn’t able to figure out myself how to apply it, I continued by asking on Stack Overflow.