SIGPIPE 13
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SubscribePosted by Allan Odgaard
Fighting Comment Spam
Update 2007-07-17: Since I installed the JS challenge almost two years ago it has blocked 83,837 POSTs. Roughly a dozen spam POSTs did defeat the challenge. Looking at the access log for these they do seem to be from actual humans (based on the initial hit having a google referrer, all resources (CSS and images) being fetched, and the delay from last GET to the POST), but it could also be a cleverly scripted browser (not sure of the “economy” of either though).
Recently I’ve received a lot of comment spam, which is fake comments posted to a blog or wiki (for me once every hour) with the purpose of increasing the page rank for a website.
Looking at the comment spam I have received, I see that more than 90% of the IP addresses are unique (infected Windows machines used as proxies?) so for the challenge I decided to run sha-1 on the visitors IP (plus a constant) and ask for that back when he submits the form.
Posted by Allan Odgaard
Deciphering an NSEvent
Since I need to handle key equivalents myself, I need to mimic how the system does it.
After having spent some time investigating this, it seems to be impossible to do with the info provided by NSEvent, but I ended up creating a heuristic which works fairly well (but isn’t perfect).
Posted by Allan Odgaard
Shell Calculator
They say that old habits die hard, and the following is probably an example of such.
Posted by Allan Odgaard
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Metadata Workarounds on Tiger
Tiger introduced functions for file metadata in the BSD layer (see man setxattr for more info).
File metadata is something most programmers have wet dreams about, and naturally I started to use these new functions in TextMate 1.1b12. After this I got several reports of kernel panics when saving files to AFP mounted volumes (personal file sharing).
Posted by Allan Odgaard
Oniguruma C++ Wrapper
I’ve recently partially switched to the Oniguruma regular expression library.
Since I also use regular expressions in my source code I’ve created a simple C++ wrapper which makes the API more friendly to my tasks. I generally work with iterators, and there are 4 tasks I often do.
Posted by Allan Odgaard
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String List Value Transformer
It’s been a while since I last wrote something — the reason for this is that I’ve been busy working on TextMate, but now that I have a free moment, let me tell you about this general tag value to string transformer I use when I bind radio or popup buttons to my user defaults (to get a string stored in the user defaults instead of an integer).
Posted by Allan Odgaard
Iterating an Array
Over at CocoaDev they are discussing how to efficiently iterate an NSArray.
I would really never ever think that the way you iterate an NSArray has any impact on the perceived performance of your program (granted you do not change the time complexity or do other stupid things), I would however think that it affects the perceived complexity of the source.
Posted by Allan Odgaard
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Increment build number for deployment builds
If we want to distribute “deployment builds” regularly (e.g. to our betatesters) it pays to automate the process. A deployment build can be done from the command line using:
xcodebuild clean
xcodebuild -buildstyle Deployment
But if we do this, we probably also want to bump the version number, or at least the build number, so that we can distinguish between the different builds.
Posted by Allan Odgaard
Disabled Image Buttons
Some time ago Apple introduced these small whitish image buttons mostly for use with table views (for adding and removing items), an example is shown here:
The buttons have three states, and Apple use images for each of these three states since the border is part of the image, so if NSControl renders it pressed or disabled, it will affect the border. Unfortunately Interface Builder only lets us set a normal image and an alternate image (which can be used as the pressed-image by setting “behavior” to “momentary change”).
Posted by Allan Odgaard
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OpenSSL for License Keys
In this article I will give an example of how one can generate and verify license keys (also known as serial numbers) using the tools included with Mac OS X, and in a way which should make it difficult for the cracker to generate his own fake license key(s).