php: minimal string

Question

how does the "tiny url" sites get so tiny ID url ?

i mean this : blabla.com/JH7

how can i get to such result? a functionality that is like md5 that does not repeat it self. thanks in advance!

Over 8 million results, did you try google? google.com/#q=php+create+tinyurl — Jeremy Harris
– Jeremy Harris, Commented Jan 31, 2012 at 1:35

Vyktor · Accepted Answer · 2012-01-31 01:36:53Z

1

For example you can simply iterate trough string:

php > $str = 'aaa';
php > $str++;
php > echo $str;
aab

The another option is to prepare function which will generate random strings containing of a-zA-Z0-9 and than generate few millions of them into db (so you could just use them when needed) or do it in loop:

while( 1){
    $rand = randomString();
    if( isUnique( $rand)){
        break;
    }
}

answered Jan 31, 2012 at 1:36

Vyktor

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1 Comment

homerun Over a year ago

thank you , that's what i was looking for! but i got a question stackoverflow.com/questions/9083311/…

deceze · Accepted Answer · 2012-01-31 01:35:10Z

1

Make a database table with the columns short_url and url.
Start by inserting the record a, example.com.
Increment short_url with each new entry (b, c, ..., a1 ...).

That's basically how these services work.

answered Jan 31, 2012 at 1:35

deceze♦

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1 Comment

dynamic Over a year ago

don't forget to use uppercase letters A-Z

drew010 · Accepted Answer · 2012-01-31 01:44:17Z

1

They use base36 encoding to convert an integer to a compact string like that.

Using PHP:

<?php
$id     = 18367;
$base36 = base_convert($id, 10, 36); // convert to base36 "e67"
$base10 = base_convert($base36, 36, 10); // "e67" back to base 10, $id

As stated by deceze, base62 is also suitable which gives you a character set of a-zA-Z0-9 instead of just a-z0-9 like base36 does.

edited Jan 31, 2012 at 1:44

answered Jan 31, 2012 at 1:36

drew010

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2 Comments

deceze Over a year ago

Probably more like base62 (upper/lower case)... :)

drew010 Over a year ago

@deceze That would make more sense, I looked around but didn't see any tinyurl's with mixed case. I think they went with 36 so there is no ambiguity between entering upper case vs lower case. The wiki article says they use base36 but I don't know if that is still correct.

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