Toby's Log page 29

Fighting form spam

Cogneato has dozens of sites with openly submittable forms on them, and they have no doubt all had some level of problems with spam submissions. Bots, and perhaps people, like to share their links or services, try to hack sites, or whatever other nefarious or annoying purposes they may have through forms, which require some sort of server side processing, and will possibly result in human processing as well, such as with sent emails, database data, or comments on a website.

Spammers have gotten more sophisticated over time, and over the last year or two, have really started to hit Cogneato’s sites hard and get past the protections we had in place. We’ve had to add protections on forms that didn’t have them before, and use more techniques to attempt to detect spam. We’ve recently added a set of checks of the submitted form data and the submitter IP address that produces a score of “spaminess” that we can then use to block the submission if the score is above a threshold. That score script is the primary purpose of this post, but I will cover the other techniques we use as well.

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PHP-FPM / Apache caching symlinks

At Cogneato, we use symlinks to point the web server to different versions of our software for websites. Sometimes, especially on our Ubuntu server, which uses PHP-FPM to serve PHP files through Apache, I was noticing problems caused by scripts being loaded from the previous symlink destination when I changed to the new one. There seems to be some sort of caching going on. The solution was to restart PHP-FPM and Apache after switching the symlinks. On Ubuntu, this looks like:

ln -s /path/to/new-version /path/to/software-link \
&& sudo service php7.2-fpm restart \
&& sudo service apache2 graceful

where the 7.2 is the version of PHP being used. Haven’t noticed the problem since.


Idea: layered E-ink plus transparent LCD screen

A fully transparent LCD screen would be layered over an E-ink screen. The LCD would provide a color display that can change rapidly for animations, video, games, etc. The E-ink would provide a low power, eye friendly display for text and other visuals not needing the LCD capabilities. The best of both worlds.

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Looking at Apache logs with command line tools

In my web development career, I have countless times needed to look at Apache logs to figure out or find out about problems with sites, monitor activity, or for various other purposes. I’ve used command line tools to help with this, often looking for strings and counting occurrences. Since I recently needed to create a command string to count unique IP’s connected to a given string in the logs, I thought I’d post about it and a few related useful commands.

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