dustindclark / grails-short-link

Grails Short Link Plugin

This plugin provides a service for generating short links and a controller for resolving target urls from a given short link. The default implementation simply translates the database ID (a long) into a short code using the configured dictionary (or the default dictionary if one is not configured).

Example config:

com:
    captivatelabs:
        shortlink:
            baseUrl: http://xyz.com 
            dictionary: abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789
            checksumDictionary: 0987654321ZYXWVUTSRQPONMLKJIHGFEDCBAzyxwvutsrqponmlkjihgfedcba
            redirectPermanent: false #if true, a permanent redirect (301) redirect will be used.  Permanent redirects should not be used where click tracking is desired.

Config	Default	Description
baseUrl	null	If specified, short links will generate as baseUrl + shortCode. Note that you will need to set up a web server to forward the path /l as necessary. If no value is specified, links will be generated as ${grails.serverUrl}/l/${shortCode}. To change /l to a different path, use UrlMappings as necessary for ShortLinkController.
dictionary	abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789	Short codes will be generated from characters in this list. Consider removing vowels to eliminate the possibility of any obscene language generation.
checksumDictionary	0987654321ZYXWVUTSRQPONMLKJIHGFEDCBAzyxwvutsrqponmlkjihgfedcba	This dictionary is provided to any class that implements ChecksumGenerator.
redirectPermanent	false	If true, a permanent redirect (301) will be used when a short link is accessed. Permanent redirects should not be used where click tracking is desired.

The default dependency injections are shown below. Note that no ClickTracker or ChecksumGenerator is provided by default. If checksum generation and/or click tracking is desired, implement and inject these classes (and keep your checksum implementation private).

shortCodeGenerator(DefaultShortCodeGenerator)
checksumGenerator(NoChecksumGenerator)
clickTracker(NoClickTracker)

WARNING: Once you start generating links, be very wary of changing your implementations and/or dictionary configuration. This will break existing links because the short codes are generated, not stored.

Note that UrlMappings have been used to map /l to ShortLinkController. If this conflicts with your existing controllers, you may override this behavior in your application's UrlMappings. If you'd like to use a custom host name (bypassing /l altogether), set the baseUrl configuration as mentioned above. You must also configure your web server to route your short link traffic appropriately. An Apache example is below:

<VirtualHost *:80>
   ServerName short.co
   RequestHeader set Host "www.longdomainname.com"
   ProxyPass / http://localhost:8080/l/ <!-- Or other machine name as necessary -->

   ErrorLog /var/log/httpd/short.co-error_log
   ProxyPreserveHost On
</VirtualHost>