old web2py blog

If you need to use captcha we strongly suggest outsourcing to recaptcha.net

It could not be easier. here is how to:

• register at recaptcha.net (they give you a private_key and a public_key)
• download this file and save it as models/recaptcha.py
• use the RECAPTCHA helper (defined in file above) as in the following...

Example:

public_key='xxx'  ### provided by recaptcha.net
private_key='xxx' ### provided by recaptcha.net
def index():
    form=FORM(RECAPTCHA(request,public_key,private_key),INPUT(_type='submit'))
    if form.accepts(request.vars,session): response.flash='done!'
    elif form.errors.has_key('captcha'): response.flash='invalid capctha'
    else: response.flash='some other error in your form'
    return dict(form=form)

The RECAPTCHA helper works very much as the input helper but it always take (request,public_key,private_key) and validates itself. If it does no pass validation an error message is stored in form.errors['captcha'] but not displayed. It is up to the developer to display the error as appropriate.