public final void doCaptcha ( StaplerRequest req , StaplerResponse rsp ) throws IOException { if ( captchaSupport != null ) { String id = req . getSession ( ) . getId ( ) ; rsp . setContentType ( "image/png" ) ; // source: https://stackoverflow.com/a/3414217 rsp . setHeader ( "Cache-Control" , "no-cache, no-store, must-revalidate" ) ; rsp . setHeader ( "Pragma" , "no-cache" ) ; rsp . setHeader ( "Expires" , "0" ) ; captchaSupport . generateImage ( id , rsp . getOutputStream ( ) ) ; } }
Generates a captcha image .