I have added a new feature to the non-free Stop-spam-plugin:
new: define languages to be blocked (available: Arabic, Chinese, Cyrillic, Greek, Hebrew, Khmer, Hangul)
This is due to an English customer who unfortunately used a simple to solve text captcha and got Chinese spam bots bombing his forum. Now he can sleep carefree, since all posts with Chinese signs get blocked before they get posted to the database.
Now the tip for developers, you can check the post string for these special language signs using:
if(preg_match("/\p{".$lang."}+/u", $posttext)) { ...
where $lang could be 'Han','Hangul','Hebrew','Arabic','Cyrillic','Greek','Khmer'.
Han stands for Chinese.
Hope that helps.
