DIY URL Shortener

gistfile1.md

Do This

1. Create dedicated domain on an Apache server that supports .htaccess
2. ssh to root directory there
3. Use random.org to create 200 random strings. (Five characters long, with digits, uppercase letters and lowercase letters).
4. Save to short-strings.txt
5. echo "RewriteRules On" > .htaccess
6. cat short-strings.txt | awk '{print "RewriteRule ^"$1"$ TO [R,L]"}' >> .htaccess
7. rm short-strings.txt
8. When you want to shorten a URL, edit .htaccess. Replace any TO with the long URL.

Example

My shortener is at s.gonze.com. I already own gonze.com, so adding a subdomain is easy. I use a dedicated subdomain because I don't want the big .htaccess file to slow down other pages.

These are the first lines in .htaccess at s.gonze.com:

# enable rewrite rules
RewriteEngine On

# if somebody requests s.gonze.com/jzPqF, send them to tinyurl.com/
RewriteRule ^jzPqF$ http://tinyurl.com/ [R,L]

# the next short URL I will create is s.gonze.com/esW7j
RewriteRule ^esW7j$ TO [R,L]

How It Works

The key thing is that the short URLs are not serial numbers, like integers from 1-10,000. This would be easy for anybody to spider, and that would be a privacy loss. Using random strings makes them a lot harder to guess, which more or less defeats spiders.