Dynamically generate short URLs for a SQL database?

Question

My client has database of over 400,000 customers. Each customer is assigned a GUID. He wants me to select all the records, create a dynamic "short URL" which includes this GUID as a parameter. Then save this short url to a field on each clients record.

The first question I have is do any of the URL shortening sites allow you to programatically create short urls on the fly like this?

Answer 1

TinyUrl allow you to do it (not widely documented), for example:

http://tinyurl.com/api-create.php?url=http://www.stackoverflow.com/

becomes http://tinyurl.com/6fqmtu

So you could have

http://tinyurl.com/api-create.php?url=http://mysite.com/user/xxxx-xxxx-xxxx-xxxx

to http://tinyurl.com/64dva66.

The guid doesn't end up being that clear, but the URLs should be unique

Note that you'd have to pass this through an HTTPWebRequest and get the response.

Answer 2

You can use Google's URL shortner, they have an API.

Here is the docs for that: http://code.google.com/apis/urlshortener/v1/getting_started.html

Answer 3

This URL is not sufficiently short:?

http://www.clientsdomain.com/?customer=267E7DDD-8D01-4F38-A3D8-DCBAA2179609

NOTE: Personally I think your client is asking for something strange. By asking you to create a URL field on each customer record (which will be based on the Customer's GUID through a deterministic algorithm) he is in fact essentially asking you to denormalize the database.

Answer 4

The algorithm URL shortening sites use is very simple:

1. Store the URL and map it to it's sequence number.
2. Convert the sequence number (id) to a fixed-length string.

Using just six lowercase letter for the second step will give you many more (24^6) combinations that the current application needs, and there's nothing preventing the use of a larger sequence at some point in time. You can use shorter sequences if you allow for numbers and/or uppercase letters.

The algorithm for the conversion is a base conversion (like when converting to hex), padding with whatever symbol represents zero. This is some Python code for the conversion:

LOWER = [chr(x + ord('a')) for x in range(25)]
DIGITS = [chr(x + ord('0')) for x in range(10)]
MAP = DIGITS + LOWER

def i2text(i, l):
        n = len(MAP)
        result = ''
        while i != 0:
                c = i % n
                result += MAP[c]
                i //= n
        padding = MAP[0]*l
        return (padding+result)[-l:]

print i2text(0,4)
print i2text(1,4)
print i2text(12,4)
print i2text(36,4)
print i2text(400000,4)
print i2text(1600000,4)

Results:

0000
0001
000c
0011
kib9
4b21

Your URLs would then be of the form http://mydomain.com/myapp/short/kib9.