> Hi everybody!
> First time poster, long time lurker. I have been struggling with
> getting recaptcha to work with GWT, and finally succeeded. I thought
> I would share how I did this. The method I solved this problem
> involves some JNSI, but also modifying some of that static content in
> your .html file. It is inelegant, but I could not get a pure JNSI
> implementation to work.
> Step 1:
> Change your .html file so that it has the proper scripts from
> recatpcha.net. Add these lines above your include for the nocache.js
> (your main GWT javascript source file):
> <script type="text/javascript" src="http://api.recaptcha.net/js/
> recaptcha_ajax.js"></script>
> <script type="text/javascript" src="recaptchaimpl.js"></script>
> You do not have recaptchaimpl.js, yet...
> Step 2:
> Make a new javascript file, called recaptchaimpl.js, and place it in
> your public directory (com.whatever.public) along with your .html file
> and .css file. You will need your recaptcha public key, which you can
> get by signing up for it at recaptcha.net. Add this text to your new
> js file:
> function init()
> {
> Recaptcha.create("YOUR_PUBLIC_KEY","recaptcha_div",{ theme:
> "clean",callback: Recaptcha.focus_response_field});
> }
> Step 3:
> Go back to your .html file, and modify the <body> tag so that it looks
> like this:
> <body onload="init()">
> Next, put in the div tags between in the body wherever you see fit:
> <div id="recaptcha_div"></div>
> When you load your page, you should now see your captcha, but we still
> need to get the challenge and response from the captcha.
> Step 4:
> Time for some JNSI. Somewhere you will have a widget that is going to
> use RPC or a POST method to send the captcha data along with whatever
> else (comment/post, signup details, etc.), and you will need to get
> the challenge and reponse from the captcha. In that widget, add the
> following two JNSI functions:
> protected native String getResponse()
> /*-{
> return $wnd.Recaptcha.get_response();
> }-*/;
> protected native String getChallenge()
> /*-{
> return $wnd.Recaptcha.get_challenge();
> }-*/;
> Call this functions to get the challenge and response, and send them
> along to your server. You can do other crap with the Recaptcha API
> using JNSI, just read up on it recaptcha.net.
> Step 5:
> You are on your own for the server implementation, but you can find
> some hints on recaptcha.net
> http://recaptcha.net/resources.html
> And as always, Google search is your friend :)
> -Ben
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