Sending Batch emails over Mailgun SMTP with ActionMailer

Recently I was checking out Mailgun's api and wanted to try batch emails over their SMTP api.

I tried it with Rails 3 ActionMailer, although it’s not very straight-forward to do, and there’s not much info around about this combination (besides this gem). If you have the same issue, try this!

Migrating from Jammit to the Asset Pipeline: Cross-check Your Expanded Bundle Paths

Switching a Rails app from Jammit to Asset Pipeline can involve a lot of work, but one of the most important pieces is ensuring you’re including the same files in the same order.

If you want to quickly cross-check that each asset bundle will include the same list of paths, try this:

Leap + Ruby

I really wanted to use the Leap SDK in Ruby after I recently got my Developer Kit.

I tried writing an FFI lib (to support all Ruby versions) but noticed it might not be sufficient.

Then I tried writing a C-extension, but realized I don’t have enough time for that right now.

Finally I tried writing a wrapper with JRuby instead (the Leap SDK includes Java libs) and it was so simple.

Pretty excited to do more with this library. Many thanks to Leap and JRuby!

I recently reprogrammed the MaKeyMaKey to control Roy the Robot’s hand, which just meant turning 6 of the input pins on MaKeyMaKey into 6 output pins, and using the Arduino Servo library to control them (my fork of the firmware is here).

I also heard about a MaKeyMaKey contest on UncommonGoods & put together this video to demo the hand.

Unfortunately, the servos weren’t strong enough to play the piano :(

Hidden Secrets of the Rails Dev: Gotchas while Migrating from 1.8 to 1.9

There are quite a few good articles on the web about changes in Ruby 1.9. 

Here are just a few changes that tripped me up a bit while making the upgrade in a Rails app:

  • String#each has been removed: use String#each_line instead
  • String#to_a was removed: use .lines.to_a instead
  • "Some string" +"hey that's bad") throws a TypeError now: force the exception using to_s
  • [1,2,3].to_s now returns "[1,2,3]" instead of "123": ie, now it’s inspect instead of join
  • incompatible encoding regexp match (ASCII-8BIT regexp with UTF-8 string): specify utf8 encoding with switch: /blah/ -> /blah/u, or"blah", Regexp::FIXEDENCODING). Read more about 1.9 and encoding at Shades of Gray 
  • 1.9.2+ doesn’t include “.” in the path ($:) anymore: use the new require_relative, or if you need to just add it explicitly: $: << "." if RUBY_VERSION =~ /1\.9/
  • 1.9 is less forgiving for spaces before args now: instead of getting a warning for the space in link_to ("home", "/"), 1.9 will now throw an error
  • 1.9 changed Method introspection: instead of method(:to_s).__file__ and method(:to_s).__line__, use method(:to_s).source_location instead
  • 1.9.3 adds new YAML parser: basically this breaks any serialized rows you might have saved in 1.9 (with Syck) with Rails’ serialization attributes. Solution here.
  • 1.9 changes Date#parse format from “MM/DD/YYY” to “DD/MM/YYYY”: this cascades to Rails’ DateTime#parse

Also, try this String monkey patch if you’re transitioning between 1.8 and 1.9. Call this whenever you need to ensure a string is utf8:

Dreams of ARel: Visualize your ActiveRecord queries

I’m currently trying to track down an ActiveRecord 3.2.* bug related to generating a count query, and thought it might be useful see a visualization of the ARel object that this query generates.

It turns out this is pretty easy!

ARel already implements a method called “to_dot” that converts your ARel into DOT, which is readable by Graphviz.

Building an API: Rails 3 vs Grape

I’ve been pretty impressed with the Grape Rack library for building an API, but I was curious how it stacks up against Rails 3, now that Rails has been Rack-ified and has steadily become more hospitable to APIs.

Using an existing Rails app with a Grape API mounted as middleware, I ran a benchmark against a vanilla API with this environment:

  • Grape 0.1.5
  • Rails 3.0.10
  • Passenger 3.0.5
  • Ruby Enterprise Edition (ruby 1.8.7), patchlevel 334
  • Macbook Pro, 2.4 GHz / 8GB, OS X 10.6.8

And it looks like Grape wins in this particular environment:

  • Grape averages 47.21 req/sec
  • Rails 3 averages 31.41  req/sec

Grape vs Rails 3 API performance

Here’s how I implemented both scenarios:

Hidden Secrets of the Rails Dev: Gotchas While Migrating from 2 to 3

Upon migrating from Rails 2 to 3, one might happen across some “gotchas”. I present a few such that you may heed caution.


This method takes a &block parameter. In Rails 2, &block will run after each callback, and halt the chain if it returns false. In Rails 3, &block will run after the :before/:around callbacks and before the :after callbacks. More has changed about callbacks, so please read the docs.


ActionMailer in Rails 3 uses a different underlying library than 2: mail instead of tmail. Setting headers in the new library will accumulate headers rather than replacing them:

m['X-Something'] = 1
m['X-Something'] = 2
m.header['X-Something'] = 3

Now m has 3 values for the X-Something header: 1, 2 and 3.


In Rails 2, touch() ultimately calls save!() and runs through all the validation and callbacks. In Rails 3, touch() saves the record using update_all(), so no validations are performed and only the new after_touch() callback is run.


In Rails 2, queries are ordered like this:

User.first(:order => "name")

In Rails 3, AREL gives us a new method for queries called order(), but remember that it will accumulate order values instead of replacing them:

# ... ORDER BY name, id .... #

Remember to use reorder() to reset the value:

# ... ORDER BY id ... #

Reorder your Authlogic persistence callbacks

One thing lacking from ActiveSupport::Callbacks, imo, is a way to reorder callbacks.

For instance, it would be nice if you could define the order in which Authlogic (which uses ActiveSupport::Callbacks) tries to persist a session (ie ‘remember’ cookie, then ‘session’ cookie, then ‘http_auth’, and so on).

Here’s some code to put at the end of your session models to prioritize their callback chains…

For Rails 2:

For Rails 3:


"SayIt ☎", a New Pronunciation Tool!

Have you ever argued with someone over the pronunciation of a word? Let “the cloud” resolve your issue!

"SayIt ☎" is my new Kynetx/Twilio/Forvo mashup that does 1 simple thing: pronounce words

Try it… send “plasmometric” to 917.740.1911 … 

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