Levenshtein Distance for Handling Redirects from Blogger 06 Apr, 2013 Levenshtein Distance for Handling Redirects from Blogger

Here's a problem I've long faced and a neat use of Levenshtein Distance.

This website started off as a blog on blogger.com. Over time, it was migrated to a self hosted Wordpress site and now runs off a Jekyll generated, Amazon S3 hosted bucket.

However, since the blogger hosted site still got a lot of traffic from search, I did not take it down. I've always wanted to redirect the traffic to my new website, but Blogger apparently only features redirects in the other direction. While Webupd8.org has a solution, I could not get it working in this case. There were at least two problems that were in the way:

  • URL structure of the current website also includes the date of publication, in addition to the year and month.
  • while migrating to Jelyll, some of the URL 'slugs' also changed.
  • I did not want to host a server to do this; I had tried this and have moved on.

To deal with these two and also handle correct redirects automatically, here is my quick solution:

  • On the blogger.com hosted website, place a redirect to a special page to handle redirects from blogger (in this case, /blog/blogger-redirect.html).
  • This special page first detects the 'referer', then extracts the year, month and slug from the blogger URL. If the referer is not found, extract the query parameter from. This is a minor optimization in case referer is set (eg. with Google Chrome); one could simply always use the query parameter method (IE and Firefox seem to remove referer).
  • It then lists the URLs on the month-page (eg. /blog/YYYY/MM/) of this website, and computes the Levenshtein's distance between the blogger-slug from the blogger URL and the slugs from the month-page URLs.
  • If the minimum amongst the computed Levenshtein distances is less than 5, automatically redirect to the URL with that minimal Levenshtein distance (example).
  • If not, admit that we made a booboo and list all pages for that month, and additionally providing the search box (example).

Notes:

  • I am pretty sure this may affect the SEO ratings, but I am unsure how exactly that will be. So, if you use it, be cautious.
  • This solution needs Javascript to work, but has the advantage of not requiring any server backend.
  • I used this JavaScript implementation of Levenshtein's distance.
  • This is the source code for my solution.
  • Yes, the source code could do with some more optimization :/


Tags  ·   Levenshtein distance  ·   redirect  ·   blogger.com  ·   Show Comments ▾


     
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