Archive for the ‘Life’ Category

Spark Core Water Sensor

June 20th, 2014

Spark Core Water Sensor

I’ve been playing around with a Spark Core, which is a small, cheap ($39) Wifi-enabled Arduino-compatible device.  As a software guy, I don’t do much with hardware, but the Spark Core makes it really easy to get going.

Anyways, I was able to hook up a Grove Water Sensor to it, and have it mounted near my sump pump.  If the pump would ever go out, the device will send me a text message (via Twilio) to alert me.

The whole setup is pretty simple, and I’ve put all the relevant firmware and software up on Github in case anyone else is interested in doing something similar.  Total hardware cost was $42, and just $1/month for Twilio.

Appcelerator Titanium Intro (2014)

June 6th, 2014

I was part of a panel during last night’s GrDevNight discussing cross-platform mobile development.  Afterwards, I gave a short presentation on Appcelerator:

Appcelerator Titanium Intro

The Happy Path: Migration Strategies for Node.js

May 5th, 2014

Today Brian Anderson, Jason Sich and I gave a presentation at GLSEC 2014 titled The Happy Path: Migration Strategies for Node.js.

It is available on Slideshare:

The Happy Path: Migration Strageies for Node.js

The presentation and code examples are also available on Github.

Minifig Collector v11.0

October 8th, 2013

My original Minifig Collector app (which was the first Android app I ever created), which has seen over 150,000 installs, just got a major facelift and some new features version 11.0.  It now has a more modern-looking UI, can import/export your figures to Brickset, and let’s you finger-swipe back and forth. Check it out!


main list
browse brickset

Unofficial LEGO® Minifigure Catalog v2.0

September 13th, 2013

Over the past few weeks I’ve been working on a new version 2.0 of the Unofficial LEGO® Minifigure Catalog app. We’ve just released the version 2.0 to the Apple iTunes and Google Play App stores.

Version 2.0 introduces tablet support along with a complete visual facelift. In addition, there are several performance improvements that make the app much faster when browsing, and I’ve added the ability to browse minifigures, sets and heads by name (in addition to by year and theme).


Check it out!

Note: LEGO® is a trademark of the LEGO Group of companies which does not sponsor, authorize or endorse this app.

SaltThePass mobile app now available on iTunes, Google Play and Amazon

July 31st, 2013

A few months ago I released, which is a password generator that will help you generate unique, secure passwords for all of the websites you visit based on a single Master Password that you remember.

I’ve been working on a mobile / offline iOS and Android app that gives you all of the features of the website.  The apps are now in the Apple iTunes App Store, Google Play App Store and the Amazon Appstore.

Let me know if you use them!
iPad, iPhone and Android apps available

How to deal with a WordPress wp-comments-post.php SPAM attack

May 9th, 2013

This morning I woke up to several website monitoring alarms going off.  My websites were becoming intermittently unavailable due to extremely high server load (>190).  It appears had been under a WordPress comment-SPAM attack from thousands of IP addresses overnight.  After a few hours of investigation, configuration changes and cleanup, I think I’ve resolved the issue.  I’m still under attack, but the changes I’ve made have removed all of the comment SPAM and have reduced the server load back to normal.

Below is a chronicle of how I investigated the problem, how I cleaned up the SPAM, and how I’m preventing it from happening again.


The first thing I do when website monitoring alarms are going off (I use Pingdom and Cacti) is to log into the server and check its load.  Load is an indicator of how busy your server is.  Anything greater than the number of CPUs on your server is cause for alarm.  My load is usually around 2.0 — when I logged in, it was 196:

[nicjansma@server3 ~]$ uptime
06:09:48 up 104 days, 11:25,  1 user,  load average: 196.32, 167.75, 156.40

Next, I checked top and found that mysqld was likely the cause of the high load because it was using 200-1000% of the CPU:

top - 06:16:45 up 104 days, 11:32, 2 users, load average: 97.69, 162.31, 161.74
Tasks: 597 total, 1 running, 596 sleeping, 0 stopped, 0 zombie
Cpu(s): 3.8%us, 19.1%sy, 0.0%ni, 10.7%id, 66.2%wa, 0.0%hi, 0.1%si, 0.0%st
Mem: 12186928k total, 12069408k used, 117520k free, 5868k buffers
Swap: 4194296k total, 2691868k used, 1502428k free, 3894808k cached

24846 mysql 20 0 26.6g 6.0g 2.6g S 260.6 51.8 18285:17 mysqld

Using SHOW PROCESSLIST in MySQL (via phpMyAdmin), I saw about 100 processes working on the wp_comments table in the WordPress database.

I was already starting to guess that I was under some sort of WordPress comment SPAM attack, so I checked out my Apache access_log and found nearly 800,000 POSTS to wp-comments-post.php since yesterday.  They all look a bit like this:

[nicjansma@server3 ~]$ grep POST access_log - - [09/May/2013:06:07:29 -0700] "POST /wp-comments-post.php HTTP/1.1" 302 20 "" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1;)"

What’s worse, the SPAMs were coming from over 3,000 unique IP addresses.  Essentially, it was a distributed denial of service (DDoS) attack:

[nicjansma@server3 ~]$ grep POST access_log | awk '{print $1}' | sort | uniq -c | wc -l
3105 was getting hundreds of thousands of POSTS to wp-comments-post.php, which was causing Apache and MySQL to do a whole lot of work checking them against Akismet for SPAM and saving in the WordPress database.  I logged into the WordPress Admin interface, which verified the problem as well:

There are 809,345 comments in your spam queue right now.


Stopping the Attack

First things first, if you’re under an attack like this, the quickest thing you can do to stop the attack is by disabling comments on your WordPress site.  There are a few ways of doing this.

One way is to go into Settings > Discussion > and un-check Allow people to post comments on new articles.

The second way is to rename wp-comments-post.php, which is what spammers use directly to add comments to your blog.  I renamed my file wp-comments-post.php.bak temporarily, so I could change it back later.  In addition, I created a 0-byte placeholder file called wp-comments-post.php so the POSTS will look to the spammers like they succeeded, but the 0-byte file takes up less server resources than a 404 page:

[nicjansma@server3 ~]$ mv wp-comments-post.php wp-comments-post.php.bak && touch wp-comments-post.php

Either of these methods should stop the SPAM attack immediately.  5 minutes after I did this, my server load was back down to ~2.0.

Now that the spammers are essentially POSTing data to your blank wp-comments-post.php file, new comments shouldn’t be appearing in your blog.  While this will reduce the overhead of the SPAM attack, they are still consuming your bandwidth and web server connections with their POSTs.  To stop the spammers from even sending a single packet to your webserver, you can create a small script that automatically drops packets from IPs that are posting several times to wp-comments-post.php.  This is easily done via a simple script like my Autoban Website Spammers via the Apache Access log post.  Change THRESHOLD to something small like 10, and SEARCHTERM to wp-comments-post.php and you will be automatically dropping packets from IPs that try to post more than 10 comments a day.

Cleaning up the Mess

At this point, I still had 800,000+ SPAMs in my WordPress moderation queue.  I feel bad for Akismet, they actually classified them all!

I tried removing the SPAM comments by going to Comments > Spam > Empty Spam, but I think it was too much for Apache to handle and it crashed.  Time to remove them from MySQL instead!

Via phpMyAdmin, I found that not only were there 800,000+ SPAMs in the database, the wp_comments table was over 3.6 GB and the wp_commentmeta was at 8.1 GB!

Here’s how to clean out the wp_comments table from any comments marked as SPAM:

DELETE FROM wp_comments WHERE comment_approved = 'spam';

OPTIMIZE TABLE wp_comments

In addition to the wp_comments table, the wp_commentmeta table has metadata about all of the comments. You can safely remove any comment metadata for comments that are no longer there:

DELETE FROM wp_commentmeta WHERE comment_id NOT IN (SELECT comment_id FROM wp_comments)

OPTIMIZE TABLE wp_commentmeta

For me, this removed 800,000+ rows of wp_comments (bringing it down from 3.6 GB to just 207 KB) and 2,395,512 rows of wp_commentmeta (bringing it down from 8.1 GB to just 136 KB).

Preventing Future Attacks

There are a few preventative measures you can take to stop SPAM attacks like these.

NOTE: Remember to rename your wp-comments-post.php.bak (or turn Comments back on) after you’re happy with the prevention techniques you’re using.

  1. Disable Comments on your blog entirely (Settings > Discussion > Allow people to post comments on new articles.) (probably not desirable for most people)
  2. Turn off Comments for older posts (spammers seem to target older posts that rank higher in search results). Here’s a way to disable comments automatically after 30 days.
  3. Rename wp-comments-post.php to something else, such as my-comments-post.php. Comment spammers often just assume your code is at the wp-comments-post.php URL and won’t check your site’s HTML to verify this is the case. If you rename wp-comments-post.php and change all occurrences of that URL in your theme, your site should continue to work while the spammers hit a bogus URL. You can follow this renaming guide for more details.
  4. Enable a Captcha for your comments so automated bots are less likely to be able to SPAM your blog. I’ve had great success with Are You A Human.
  5. The Autoban Website Spammers via the Apache Access log post describes my method for automatically dropping packets from bad citizen IP addresses.

After all of these changes, my server load is back to normal and I’m not getting any new SPAM comments.  The DDoS is still hitting my server, but their IP addresses are slowly getting packets dropped via my script every 10 minutes.

Hopefully these steps can help others out there.  Good luck! Fighting spammers is a never-ending battle!

2012 Minifigures Available

April 17th, 2013

Thanks to Christoph‘s hard work taking photos of all 529 minifigures released in 2012, the 2012 minifigs are now available for purchase in the Unofficial Minifigure Catalog app.

To purchase the update, first update the database to the latest version (Settings > Database) and then go to Settings > Collections and look for the purchase button.


April 15th, 2013

UserTiming is one of the W3C specs that I helped design while working at Microsoft through the W3C WebPerf working group.  It helps developers measure the performance of their web applications by giving them access to high precision timestamps. It also provides a standardized API that analytics scripts and developer tools can use to display performance metrics.

UserTiming is natively supported in IE 10 and prefixed in Chrome 25+.  I wanted to use the interface for a few of my projects so I created a small polyfill to help patch other browsers that don’t support it natively. Luckily, a JavaScript version of UserTiming can be implemented and be 100% API functional — you just lose some precision and performance vs. native browser support.

So here it is: UserTiming.js


UserTiming.js is a polyfill that adds UserTiming support to browsers that do not natively support it.

UserTiming is accessed via the PerformanceTimeline, and requires support, so UserTiming.js adds a limited version of these interfaces if the browser does not support them (which is likely the case if the browser does not natively support UserTiming).

As of 2013-04-15, UserTiming is natively supported by the following browsers:

  • IE 10+
  • Chrome 25+ (prefixed)

UserTiming.js has been verified to add UserTiming support to the following browsers:

  • IE 6-9
  • Firefox 3.6+ (previous versions not tested)
  • Safari 4.0.5+ (previous versions not tested)
  • Opera 10.50+ (previous versions not tested)

UserTiming.js will detect native implementations of UserTiming, and the PerformanceTimeline and will not make any changes if those interfaces already exist.  When a prefixed version is found, it is copied over to the unprefixed name.

UserTiming.js can be found on GitHub and as the npm usertiming module.

New Adventures: Why I’m Leaving Microsoft and What’s Next

September 14th, 2011

Six years ago, fresh out of college, I packed up my life into a couple of moving boxes and headed out to the Pacific Northwest to take a job at Microsoft.  Since then, I’ve been lucky enough to work on some amazing projects – a large scale performance validation infrastructure for Windows 7, a world-class browser, and have helped shape the future of the web by collaborating in the W3C webperf working group.  It’s been a great place to work – I’ve made some amazing friends, learned more than I ever would have imagined, and have been often humbled by how amazing my coworkers are.

This Friday will be my last day at Microsoft.  It was a tough decision to leave, and there are many things I will miss about the company, my work, and my coworkers.  Microsoft is a great company, the benefits are amazing, and you get to work with a ton of awesome people.  I’ve grown in so many ways by just being able to interact with and learn from my coworkers.  I’ll miss those interactions.

On the other hand, for the past fifteen years, I have been building software, websites, and now mobile apps in my spare time.  I’ve always used these side projects to satisfy a need to be creative, to learn and explore new technologies, and to have fun.  Some of these projects have grown beyond what I would have ever expected them to be.  It’s been tough finding time to work on them – after a long day of mind-bending work, staring at a monitor for another couple hours isn’t always at the top of my list of things to do.  But I get a lot of pleasure out of being creative, so I’ll often stay up late working on this or that.

And so, I’ve always wondered what I could accomplish if those projects were my only job?

Starting Monday, I am taking the big, scary step of becoming my own boss.  I’m still not 100% sure what that means, and I’ll let you know a year from now how it has worked out.  I’m excited to build, to be creative, to learn, and to share.  It’s time for me to get serious about some of the projects I’ve already put hundreds of hours into and to take them to the next level.

In addition to those projects, one of my passions is performance, on both the desktop and the web.  My focus at Microsoft was on perf features and analysis, where I developed a massive performance regression testing system for Windows 7.  I built performance features for Internet Explorer 9, and collaborated in the W3C webperf working group.  I hope to continue learning, exploring and even teaching others about performance in the future, through research and experimentation with my own projects.

There are a ton of things I want to accomplish, and I know I’ll have to work hard to provide for my family.  It’s not easy walking away from a comfy salary and great benefits, with the knowledge that you have to make up for all of it on your own.  Thankfully I have a head start with some successful websites and apps, but I know I’m going to have to put a lot of hard work into taking them to the next level.

Wish me luck.