... somewhere there you should see the sanitized URL ...

But this would mean, to open the browser, login to blog, type in title, clicking preview, copying the sanitized URL, switch to script, paste sanitized URL, copy generated hmtl code, switch back to browser and finally paste html code. This is not very user friendly.

My plan was to write the posting offline including the generated html code without all this window switching.

But you're right, this would be a possible solution. A quick and dirty one. ;) ( which came to my mind already)

Perhaps I wasn't clear - you have to do that only once - then you know the mapping, assuming that it stays constant. Once you have that mapping, it's trivial to re-implement in perl.

You should also check if there are additional rules (like collapsing multiple non-printable characters into one, or something like that).