[unique_id] at tagSwap.net: Open Source Lasso Code

[unique_id]

Description

Link: [unique_id]

Author: Johan Sölve

Category: Utility

Version: 6.x

License: Public Domain

Posted: Jan. 18, 2006

Updated: Sep. 06, 2006

More by this author...

Returns shortest possible (?) unique string based on current date, time, milliseconds and a random number. The length of the unique ID depends on the length of #charlist. This version use lowercase letters and numbers (a-z, 0-9) and the length of the unique ID becomes 11 to 13 characters.
Making #charlist longer by including also uppercase letters (a-z, A-Z, 0-9) creates a slightly shorter string of 10-11 characters but will require case sensitive handling. By removing also the random number part, the length of the unique ID can be reduced to 8 characters.

Johan Sölve 2004-11-17

Parameters

none

Sample Usage

[var: 'imagename' = unique_id + '.jpg']
[$imagename]

Result: dnnyunqa74z1.jpg

Source Code

Click the "Download" button below to retrieve a copy of this tag, including the complete documentation and sample usage shown on this page. Place the downloaded ".inc" file in your LassoStartup folder, restart Lasso, and you can begin using this tag immediately.

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<?lassoscript
define_tag: 'unique_id';
	// returns shortest possible unique string based on current date, time, milliseconds, IP and a random number
	// Johan Sölve 2004-11-17
	
	local: 'charlist'='stu7ghi3jk4yz9ld0ef2vwx8mno5abc1pqr6',
		'date'=date, 
		'seconds'=0, 
		'output'='';
	local: 'base'=(#charlist -> size) - 1,
		'leapyear'=(date: (#date->format: '%Y-03-01 12:00:00'));
	#leapyear -> (subtract: -day=1);
	#leapyear=integer: ((#leapyear->day)==29);
	
	#seconds += ((#date->year%100) * (365 + #leapyear) + (#date -> dayofyear)) * 3600 * 24;
	#seconds += (#date->hour)*3600 + (#date->minute)*60 + (#date->second);
	#seconds *= 1000;
	#seconds += (#date -> millisecond);
	
	// add the client IP
	// local: 'ip'=(string: client_ip)->(split: '.');
	// use simulated random ip instead of real client ip to get more variation
	local: 'ip'=(array);
	loop: 2;
		#ip -> (insert: (math_random: -min=1, -max=255));
	/loop;
	
	local: 'ip_num'=0;

	iterate: #ip, (local: 'part');
		#ip_num += integer: (math_pow: 256, (#ip->size - loop_count)) * (integer: #part);
	/iterate;

	local: 'converted'=(array);
	
	while: #seconds>0;
		#converted->(insert: (#seconds % #base), 1);
		#seconds = #seconds / #base;
	/while;
	
	// add a single random char
	#converted -> insert: (math_random: -min=0, -max=#base);

	while: #ip_num>0;
		#converted->(insert: (#ip_num % #base), 1);
		#ip_num = #ip_num / #base;
	/while;

	while: #converted->size > 0;
		if: loop_count % 4 == 1;
			// try to distribute the last items as evenly as possible since they change the most
			#output += #charlist->(get: ((#converted->last) + 1));
			#converted->remove;
		/if;
		if: #converted->size > 0;
			#output += #charlist->(get: ((#converted->first) + 1));
			#converted->(remove: 1);
		/if;
	/while;

	return: #output;

/define_tag;
?>

Related Tags

[c5_shortunique]

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