The earliest memory I have of ‘programming’ is in the early/mid 90s when my father brought home a computer from work. We could play games on it … so of course I took the spreadsheet program he used (LOTUS 123, did I date myself with that?) and tried to modify it to print out a helpful message for him. It … halfway worked? At least I could undo it so he could get back to work…

After that, I picked up programming for real in QBASIC (I still have a few of those programs lying around), got my own (junky) Linux desktop from my cousin, tried to learn VBasic (without a Windows machine), and eventually made it to high school… In college, I studied computer science and mathematics, mostly programming in Java/.NET, although with a bit of everything in the mix. A few of my oldest programming posts on this blog are from that time.

After that, on to grad school! Originally, I was going to study computational linguistics, but that fell through. Then programming languages (the school’s specialty). And finally I ended up studying censorship and computer security. That’s about where I am today!

But really, I still have a habit of doing a little bit of everything. Whatever seems interesting at the time!

Finding AWS IAM users by access key

2015-07-22

Every once in a while¹, I find myself with an AWS access key and need to figure out who in the world it belongs to. Unfortunately, so far as I’ve been able to find, there’s no way to directly do this in either the AWS console or with the AWS api.

Configuring Websockets behind an AWS ELB

2015-07-20

Recently at work, we were trying to get an application that uses websockets working on an AWS instance behind an ELB (load balancer) and nginx on the instance.

If you’re either not using a secure connection or handling the cryptography on the instance (either in nginx or Flask), it works right out of the box. But if you want the ELB to handle TLS termination it doesn’t work nearly as well… Luckily, after a bit of fiddling, I got it working.

Update 2018-05-31: A much easier solution, [https://aws.amazon.com/blogs/aws/new-aws-application-load-balancer/](just use an ALB):

WebSocket allows you to set up long-standing TCP connections between your client and your server. This is a more efficient alternative to the old-school method which involved HTTP connections that were held open with a “heartbeat” for very long periods of time. WebSocket is great for mobile devices and can be used to deliver stock quotes, sports scores, and other dynamic data while minimizing power consumption. ALB provides native support for WebSocket via the ws:// and wss:// protocols.

Automagically storing Python objects in Redis

2015-07-16

When you’re starting out on a simple web application, eventually¹ you will reach the point where you need to store some form of persistant data. Basically, you have three options²:

Store the information in flat files on the file system
Store the information in a database (MySQL, SQLite etc)
Store the information in a key/value store (mongoDB, reddis)

There are all manner of pros and cons to each, in particular how easy they are to get started in, how well they fit the data you are using, and how well they will scale horizontally (adding more machines rather than bigger ones).

Backing up Moves Data

2015-07-10

Another backup post, this time I’m going to back up my data from the Moves App (step counter + GPS tracker). Theoretically, it should be possible to get this same data from the app as part of my iOS Backup series, but the data there is in a strange binary format. Much easier to use their API.

Scraping Kindle Highlights

2015-07-02

Edit March 2020: It seems the page ‘your highlights’ page on Amazon no longer exists, so this script no longer works. I’ll probably see if I can pull them from Goodreads instead now that the integration is there or directly from my Kindle, but for the moment, this script does not work.

As part of an ongoing effort to backup all the things, combined with a rather agressive 2015 Reading List, I wanted to the ability to back up any sections that I’ve highlighted on my Kindle. Unfortunately, Amazon doesn’t seem to have an API to do that, but why should that stop me?

Using a combination of Python and the Python libraries Requests and BeautifulSoup¹, it’s entirely possible to write a Python script that will log into Amazon, get a list of all of the books on your account, and download the highlights for each.

Let’s do it!

Generating YouTube user RSS feeds

2015-05-11

On 4 March 2014, YouTube deprecated the v2.0 API for YouTube (source). One of the unfortunate side effects was that RSS feeds for user uploads were included in what was deprecated.

Previously, you could get an RSS feed with a link of the form: https://gdata.youtube.com/feeds/base/users/{user}/uploads For the longest time, even after the deprecation, those links still worked, but a couple weeks ago, more and more of the video feeds I was subscribed to started redirecting to YouTube Help account. As thrilling as that channel is, it’s not what I’m looking for.

Let’s fix it.

Tupper's self-referential formula

2015-05-07

Quick post today. Let’s implement Tupper's self-referential formula in Racket!

\frac{1}{2} < \left \lfloor mod \left ( \left \lfloor \frac{y}{17} 2^{-17 \lfloor x \rfloor - mod(\lfloor y \rfloor, 2)} \right \rfloor, 2 \right ) \right \rfloor

(tupper 960939379918958884971672962127852754715004339660129306651505519271702802395266424689642842174350718121267153782770623355993237280874144307891325963941337723487857735749823926629715517173716995165232890538221612403238855866184013235585136048828693337902491454229288667081096184496091705183454067827731551705405381627380967602565625016981482083418783163849115590225610003652351370343874461848378737238198224849863465033159410054974700593138339226497249461751545728366702369745461014655997933798537483143786841806593422227898388722980000748404719)

That’s the result of graphing the above function at a point rather far away from the origin. Specifically, where y is around that crazy big number. Look familiar?

It's all Greek to me

2015-04-17

A few days ago an interesting article came across my RSS feeds: It’s All Greek (or Chinese or Spanish or…) to Me. Basically, in English, when you’re confused, you’ll often say ‘It’s all Greek to me’. It turns out that man (if not all) languages around the world have a similar saying, but the target varies. Luckily, Wikipedia has a lovely page about it: Greek to me.

A Quick Look at RC4

2015-04-14

In cryptography work, RC4 (Rivest Cipher 4) is well known as both one of the easiest to implement and fastest to run symmetric encryption algorithms. Unfortunately, over time there have been a number of attacks on RC4, both in poorly written protocols (such as in the case of WEP) or statistical attacks against the protocol itself.

Still, for how well it formed, it’s an amazingly simple algorithm, so I decided to try my hand at implementing it.

Generating perfect portmanteaus

2015-04-07

A quick programming post, since it’s been a while, inspired by this video:

I’m not going to go quite as far as that, but I thought it would be interesting to write up some quick code to generate portmanteaus¹.