tbje/CaptchaSnippet.scala

## captcha.html
<lift:surround with="default" at="content">
<head>
	<script type="text/javascript" src="http://api.recaptcha.net/js/recaptcha_ajax.js" />
	<script type="text/javascript">
	function create(){
		Recaptcha.create("your public key", "recaptcha_div", {
			theme: "clean"}
		);
	}
	function setHidden(){
		document.getElementById('challenge').value=Recaptcha.get_challenge()
		document.getElementById('response').value=Recaptcha.get_response()
	}
	</script>
</head>
<lift:CaptchaSnippet:form form="POST" onsubmit="setHidden()">
	<lift:msgs/>
	<x:email />
	<x:challenge id="challenge"/>
	<x:response id="response"/>
	<div name="recaptcha_div" id="recaptcha_div" />
	<script>create()</script>
	<x:submit/>
</lift:CaptchaSnippet:form>
</lift:surround>

## CaptchaSnippet.scala
import net.liftweb.http._
import net.liftweb.http.SHtml._
import net.liftweb.util._
import net.liftweb.util.Helpers._
import net.liftweb.common._

import java.net.{HttpURLConnection, MalformedURLException, URL, URLEncoder}
import java.io.{BufferedReader, InputStreamReader, IOException, OutputStreamWriter}

import scala.xml._

class CaptchaSnippet extends StatefulSnippet with Logger {

	val privateKey = "your private key"
	val dispatch: DispatchIt = {
		case "form" => form _
	}

	var email = "Default value"

	def form(html: NodeSeq) : NodeSeq = {
		var challenge = ""
		var response = ""
		bind("x", html,
				"email" -> text(email, (x:String) => email=x),
				"challenge" -%> hidden((x:String)=>challenge=x, ""),
				"response" -%> hidden((x:String)=>response=x, ""),
				"submit" -> submit("Send", () => {
					if (verifyCaptcha(challenge, response)) {
						submitAction(email)
					} else {
						S.error("Recaptcha input not correct"))
					}
				}
		)
	}

	def submitAction(email: String) { /*processing*/ }

	def verifyCaptcha(challenge: String, response: String) : Boolean = {
		val url = new URL("http://api-verify.recaptcha.net/verify")
		val con = url.openConnection.asInstanceOf[HttpURLConnection]
		con.setDoOutput(true)
		con.setRequestMethod("POST")
		val writer = new OutputStreamWriter(con.getOutputStream)
		writer.write("privatekey=" + privateKey)
		writer.write("&remoteip=" + S.containerRequest.map(_.remoteAddress)
			.openOr("localhost"))
		writer.write("&challenge=" + challenge)
		writer.write("&response=" + response)
		writer.close

		if (con.getResponseCode == HttpURLConnection.HTTP_OK) {
			val reader = new BufferedReader(
				new InputStreamReader(con.getInputStream))
			val res : Boolean = reader.readLine match {
				case "true" => true
				case _ => false
			}
			reader.close
			res
		} else {
			error("Connection problem to reCaptcha")
			false
		}
	}

}

## std.html
<script type="text/javascript"
   src="http://api.recaptcha.net/challenge?k=<your_public_key>">
</script>

<noscript>
   <iframe src="http://api.recaptcha.net/noscript?k=<your_public_key>"
       height="300" width="500" frameborder="0"></iframe><br>
   <textarea name="recaptcha_challenge_field" rows="3" cols="40">
   </textarea>
   <input type="hidden" name="recaptcha_response_field"
       value="manual_challenge">
</noscript>
	<lift:surround with="default" at="content">
	<head>
	<script type="text/javascript" src="http://api.recaptcha.net/js/recaptcha_ajax.js" />
	<script type="text/javascript">
	function create(){
	Recaptcha.create("your public key", "recaptcha_div", {
	theme: "clean"}
	);
	}
	function setHidden(){
	document.getElementById('challenge').value=Recaptcha.get_challenge()
	document.getElementById('response').value=Recaptcha.get_response()
	}
	</script>
	</head>
	<lift:CaptchaSnippet:form form="POST" onsubmit="setHidden()">
	<lift:msgs/>
	<x:email />
	<x:challenge id="challenge"/>
	<x:response id="response"/>
	<div name="recaptcha_div" id="recaptcha_div" />
	<script>create()</script>
	<x:submit/>
	</lift:CaptchaSnippet:form>
	</lift:surround>
	import net.liftweb.http._
	import net.liftweb.http.SHtml._
	import net.liftweb.util._
	import net.liftweb.util.Helpers._
	import net.liftweb.common._

	import java.net.{HttpURLConnection, MalformedURLException, URL, URLEncoder}
	import java.io.{BufferedReader, InputStreamReader, IOException, OutputStreamWriter}

	import scala.xml._

	class CaptchaSnippet extends StatefulSnippet with Logger {

	val privateKey = "your private key"
	val dispatch: DispatchIt = {
	case "form" => form _
	}

	var email = "Default value"

	def form(html: NodeSeq) : NodeSeq = {
	var challenge = ""
	var response = ""
	bind("x", html,
	"email" -> text(email, (x:String) => email=x),
	"challenge" -%> hidden((x:String)=>challenge=x, ""),
	"response" -%> hidden((x:String)=>response=x, ""),
	"submit" -> submit("Send", () => {
	if (verifyCaptcha(challenge, response)) {
	submitAction(email)
	} else {
	S.error("Recaptcha input not correct"))
	}
	}
	)
	}

	def submitAction(email: String) { /processing/ }

	def verifyCaptcha(challenge: String, response: String) : Boolean = {
	val url = new URL("http://api-verify.recaptcha.net/verify")
	val con = url.openConnection.asInstanceOf[HttpURLConnection]
	con.setDoOutput(true)
	con.setRequestMethod("POST")
	val writer = new OutputStreamWriter(con.getOutputStream)
	writer.write("privatekey=" + privateKey)
	writer.write("&remoteip=" + S.containerRequest.map(_.remoteAddress)
	.openOr("localhost"))
	writer.write("&challenge=" + challenge)
	writer.write("&response=" + response)
	writer.close

	if (con.getResponseCode == HttpURLConnection.HTTP_OK) {
	val reader = new BufferedReader(
	new InputStreamReader(con.getInputStream))
	val res : Boolean = reader.readLine match {
	case "true" => true
	case _ => false
	}
	reader.close
	res
	} else {
	error("Connection problem to reCaptcha")
	false
	}
	}

	}
	<script type="text/javascript"
	src="http://api.recaptcha.net/challenge?k=<your_public_key>">
	</script>

	<noscript>
	<iframe src="http://api.recaptcha.net/noscript?k=<your_public_key>"
	height="300" width="500" frameborder="0"></iframe><br>
	<textarea name="recaptcha_challenge_field" rows="3" cols="40">
	</textarea>
	<input type="hidden" name="recaptcha_response_field"
	value="manual_challenge">
	</noscript>