diff --git a/LICENSE b/LICENSE --- a/LICENSE +++ b/LICENSE @@ -1,4 +1,4 @@ -Copyright (c)2012, Lars Petersen +Copyright (c)2012, Lars Petersen; (c)2014, Michael Ledger All rights reserved. diff --git a/snaplet-recaptcha.cabal b/snaplet-recaptcha.cabal --- a/snaplet-recaptcha.cabal +++ b/snaplet-recaptcha.cabal @@ -1,87 +1,37 @@ --- snaplet-recaptcha.cabal auto-generated by cabal init. For --- additional options, see --- http://www.haskell.org/cabal/release/cabal-latest/doc/users-guide/authors.html#pkg-descr. --- The name of the package. -Name: snaplet-recaptcha - --- The package version. See the Haskell package versioning policy --- (http://www.haskell.org/haskellwiki/Package_versioning_policy) for --- standards guiding when and how versions should be incremented. -Version: 0.1 - --- A short (one-line) description of the package. -Synopsis: A ReCAPTCHA verification snaplet with connection sharing. - --- A longer description of the package. -Description: This snaplet handles the interfacing with Google's ReCaptcha verification API. - It uses `http-conduit` which manages a connection pool. On the one hand - this avoid the overhead of reconnecting for every single captcha request and - on the other hand limits the use of the server's resources. - --- The license under which the package is released. -License: BSD3 - --- The file containing the license text. -License-file: LICENSE - --- The package author(s). -Author: Lars Petersen - --- An email address to which users can send suggestions, bug reports, --- and patches. -Maintainer: info@lars-petersen.net - --- A copyright notice. --- Copyright: - -Category: Web - -Build-type: Simple - --- Extra files to be distributed with the package, such as examples or --- a README. --- Extra-source-files: - --- Constraint on the version of Cabal needed to build this package. -Cabal-version: >=1.10 - -Library - Hs-Source-Dirs: src - Exposed-Modules: Snap.Snaplet.ReCaptcha - Default-Language: Haskell2010 - Build-Depends: base >= 4 && < 5 - , data-lens - , data-lens-template - , bytestring - , failure - , conduit - , http-conduit - , http-types - , snap-core - , snap +-- Initial snaplet-recaptcha.cabal generated by cabal init. For further +-- documentation, see http://haskell.org/cabal/users-guide/ -Executable recaptcha-test - Main-Is: recaptcha-test.hs - Hs-Source-Dirs: src - Other-Modules: Snap.Snaplet.ReCaptcha - Default-Language: Haskell2010 - Build-Depends: base >= 4 && < 5 - , data-lens - , data-lens-template - , bytestring - , text - , failure - , snap-core - , snap-server - , snap - , blaze-html - , failure - , conduit - , http-conduit - , http-types +name: snaplet-recaptcha +version: 1.0 +synopsis: A ReCAPTCHA verification snaplet with Heist integration and connection sharing. +-- description: +homepage: http://github.com/mikeplus64/snaplet-recaptcha +license: BSD3 +license-file: LICENSE +author: Mike Ledger, Lars Petersen +maintainer: Mike Ledger +-- copyright: +category: Web +build-type: Simple +-- extra-source-files: +cabal-version: >=1.10 -Source-Repository head - type: git - location: http://github.com/lpeterse/snaplet-recaptcha.git +library + exposed-modules: Snap.Snaplet.ReCaptcha + , Snap.Snaplet.ReCaptcha.Example + build-depends: base < 5 + , lens + , heist >= 0.14 && <0.15 + , snap >= 0.13 && <0.14 + , blaze-builder + , MonadCatchIO-transformers + , mtl + , aeson + , bytestring + , configurator + , text + , http-conduit >=2.1 + hs-source-dirs: src + default-language: Haskell2010 diff --git a/src/Snap/Snaplet/ReCaptcha.hs b/src/Snap/Snaplet/ReCaptcha.hs --- a/src/Snap/Snaplet/ReCaptcha.hs +++ b/src/Snap/Snaplet/ReCaptcha.hs @@ -1,138 +1,273 @@ -{-# LANGUAGE OverloadedStrings, FlexibleInstances, MultiParamTypeClasses, TemplateHaskell #-} +{-# LANGUAGE DeriveDataTypeable #-} +{-# LANGUAGE FlexibleInstances #-} +{-# LANGUAGE MultiParamTypeClasses #-} +{-# LANGUAGE NoMonomorphismRestriction #-} +{-# LANGUAGE OverloadedStrings #-} +{-# LANGUAGE TemplateHaskell #-} -- | -- Module : Snap.Snaplet.ReCaptcha --- Copyright : (c) Lars Petersen 2012 +-- Copyright : (c) Mike Ledger 2014 +-- (c) Lars Petersen 2012 +-- -- License : BSD-style -- --- Maintainer : info@lars-petersen.net +-- Maintainer : mike@quasimal.com, info@lars-petersen.net -- Stability : experimental -- Portability : portable --- --- This is a snaplet for google's ReCaptcha verification api. This library uses `http-conduit` and keeps connections alive (a maximum of 10 by now). This is an important point in order to avoid denial of service attacks. --- --- Include it into your application like this: -- --- > import Snap.Snaplet.ReCaptcha --- > --- > data MyApplication = MyApplication { _recaptcha :: Snaplet ReCaptcha, ... } --- > --- > $(makeLenses [''MyApplication]) --- > --- > instance HasReCaptcha MyApplicaiton where --- > recaptchaLens = subSnaplet recaptcha --- > --- > myApplication :: SnapletInit MyApplication --- > myApplication --- > = makeSnaplet --- > "MyApplication" --- > "" --- > Nothing --- > $ do r <- embedSnaplet "recaptcha" recaptcha $ initReCaptcha "YOUR_PRIVATE_KEY" --- > return $ MyApplication { _recaptcha = r, ... } +-- This is a snaplet for google's ReCaptcha verification api. This library uses +-- `http-conduit` and keeps connections alive (a maximum of 10). This is an +-- important point in order to avoid denial of service attacks. -- - -module Snap.Snaplet.ReCaptcha - ( -- * Snaplet and Initialization - ReCaptcha () - , HasReCaptcha (..) - , initReCaptcha - -- * Handlers - , verifyCaptcha - -- * Types - , PrivateKey - , ReCaptchaResult (..) - ) where +-- See 'Snap.Snaplet.ReCaptcha.Example' and the docs provided here for example +-- usage. +-- -import Data.Lens.Common -import Data.Lens.Template +module Snap.Snaplet.ReCaptcha + ( -- * Snaplet and Initialization + ReCaptcha () + , HasReCaptcha (..) + , initReCaptcha + , initReCaptcha' + -- * Handlers + , checkCaptcha + , withCaptcha + , getCaptcha + -- * Types + , Captcha(..) + , PrivateKey + , SiteKey + -- * Extra + , cstate + , recaptchaScript, recaptchaDiv + ) where -import qualified Data.ByteString as BS -import qualified Data.ByteString.Lazy as BSL +import qualified Blaze.ByteString.Builder as Blaze +import Control.Applicative +import Control.Lens +import Control.Monad.Reader (runReaderT) -import Data.Monoid -import Control.Applicative -import Control.Failure -import Control.Exception (throw, try) -import Control.Monad.Trans.Resource (runResourceT) +import qualified Data.Aeson as JSON +import qualified Data.Aeson.TH as JSON +import qualified Data.ByteString.Char8 as BS +import qualified Data.Configurator as Conf +import Data.Text (Text) +import Data.Text.Encoding (encodeUtf8) -import Network.HTTP.Types (renderSimpleQuery) -import Network.HTTP.Conduit as HTTP -import Snap +import Data.Foldable (fold, for_, toList) +import Data.Monoid +import Data.Typeable -data ReCaptcha - = ReCaptcha - { privateKey :: PrivateKey - , connectionManager :: Manager - } +import Heist +import Heist.Compiled -class HasReCaptcha b where - recaptchaLens :: Lens (Snaplet b) (Snaplet ReCaptcha) +import qualified Network.HTTP.Client.Conduit as HTTP -type PrivateKey = BS.ByteString +import Snap +import Snap.Snaplet.Heist.Compiled --- | The private key must be 40 characters long and encoded just like you get it from Google. -initReCaptcha :: PrivateKey -> SnapletInit b ReCaptcha -initReCaptcha key - = makeSnaplet - "ReCaptcha" - "" - Nothing - $ do man <- liftIO (newManager def) - if BS.length key /= 40 - then fail "ReCaptcha: private key must be exactly 40 chars long" - else return $ ReCaptcha key man +type PrivateKey = BS.ByteString +type SiteKey = BS.ByteString +type UserIP = BS.ByteString +type UserAnswer = BS.ByteString -data ReCaptchaResult +data Captcha = Success - -- Taken from the official ReCaptcha Api documentation - | Failure BSL.ByteString - | ConnectionError HttpException - -- Misc - | MissingArguments + | Failure + -- | Errors returned by the Captcha. See + -- for possible error codes. Note that 'Failure' is used for the case that the + -- only error code returned is "invalid-input-response". + | Errors [Text] + -- | The server didn't respond with the JSON object required as per + -- + | InvalidServerResponse + -- | There was no "recaptcha_response_field" parameter set in the user request. + | MissingResponseParam + deriving (Show, Typeable) -instance Failure HttpException (Handler b ReCaptcha) where - failure = throw +data ReCaptcha = ReCaptcha + { connectionManager :: !HTTP.Manager + , recaptchaQuery :: !(UserIP -> UserAnswer -> HTTP.Request) + , _cstate :: !Captcha + } deriving (Typeable) --- | You may use captcha verification troughout your whole application like this: +makeLenses ''ReCaptcha + +class HasReCaptcha b where + captchaLens :: SnapletLens (Snaplet b) ReCaptcha + +instance HasReCaptcha ReCaptcha where + captchaLens = id + +-- This is kinda lame - should we just parse it manually? +data ReCaptchaResponse = ReCaptchaResponse + { success :: !Bool + , error_codes :: !(Maybe [Text]) + } + +JSON.deriveJSON JSON.defaultOptions ''Captcha + +JSON.deriveFromJSON JSON.defaultOptions + { JSON.fieldLabelModifier = map $ \c -> case c of + '_' -> '-' + _ -> c + } ''ReCaptchaResponse + +initialiser :: Maybe (Snaplet (Heist b)) -> (SiteKey, PrivateKey) + -> Initializer b v ReCaptcha +initialiser mheist (site,key) = do + -- this has to parse for the snaplet to work at all + req <- liftIO (HTTP.parseUrl "https://www.google.com/recaptcha/api/siteverify") + man <- liftIO HTTP.newManager + for_ mheist (\heist -> addReCaptchaHeist heist site) + return ReCaptcha + { connectionManager = man + , recaptchaQuery = \ip answer -> + HTTP.urlEncodedBody + [ ("secret" , key) + , ("response" , answer) + , ("remoteip" , ip) ] + req + , _cstate = Failure + } + +-- | Initialise the 'ReCaptcha' snaplet. You are required to have "site_key" and +-- "secret_key" set in the snaplet's configuration file. See 'initReCaptcha\'' +-- if you don't want to use Snap's snaplet configuration mechanism. -- --- > myHandler :: (HasReCaptcha b) => Handler b SomeSubSnaplet () --- > myHandler --- > = do c <- verifyCaptcha --- > case c of --- > Success -> .. -- captcha successfully solved --- > _ -> .. -- something went wrong +-- This provides optional Heist support, which is implemented using +-- 'recaptchaScript' and 'recaptchaDiv'. +initReCaptcha :: Maybe (Snaplet (Heist b)) -> SnapletInit b ReCaptcha +initReCaptcha heist = + makeSnaplet "recaptcha" "ReCaptcha integration" Nothing $ + initialiser heist =<< do + conf <- getSnapletUserConfig + (,) <$> require conf "site_key" + <*> require conf "secret_key" + where + require conf field = do + v <- liftIO (Conf.lookup conf field) + case v of + Just v' -> return v' + Nothing -> do + spath <- BS.pack `fmap` getSnapletFilePath + err <- errorMsg (encodeUtf8 field <> " not in the config " <> spath + <> "/devel.cfg") + fail (BS.unpack err) + +-- | Same as 'initReCaptcha', but passing the site key and private key +-- explicitly - no configuration on the filesystem is required. +initReCaptcha' :: Maybe (Snaplet (Heist b)) -> (SiteKey, PrivateKey) + -> SnapletInit b ReCaptcha +initReCaptcha' heist keys = + makeSnaplet "recaptcha" "ReCaptcha integration" Nothing + (initialiser heist keys) + +addReCaptchaHeist :: Snaplet (Heist b) -> BS.ByteString -> Initializer b v () +addReCaptchaHeist heist site = addConfig heist $ mempty &~ do + scCompiledSplices .= do + "recaptcha-div" ## pureSplice id (return (recaptchaDiv site)) + "recaptcha-script" ## pureSplice id (return recaptchaScript) + +-- | @ @ +recaptchaScript :: Blaze.Builder +recaptchaScript = Blaze.fromByteString + "" + +-- | For use in a HTML form. +recaptchaDiv :: BS.ByteString -> Blaze.Builder +recaptchaDiv site = Blaze.fromByteString $! + "
" + +-- | Get the ReCaptcha result by querying Google's API. -- --- You don't need to extract the challenge and response paramters from the request. This is all handled by the snaplet. Just make sure the parameters `recaptcha_challenge_field` and `recaptcha_response_field` are contained in the user's request. Otherwise the `verifyCaptcha` call will return `MissingArguments`. +-- This requires a "g-recaptcha-response" (POST) parameter to be set in the +-- current request. -- -verifyCaptcha :: (HasReCaptcha b) => Handler b c ReCaptchaResult -verifyCaptcha - = do mchallenge <- getParam "recaptcha_challenge_field" - mresponse <- getParam "recaptcha_response_field" - case (mchallenge, mresponse) of - (Just challenge, Just response) - -> do man <- withTop' recaptchaLens (gets connectionManager) - privatekey <- withTop' recaptchaLens (gets privateKey) - rq <- withTop' recaptchaLens (parseUrl "http://www.google.com/recaptcha/api/verify") - remoteip <- rqRemoteAddr <$> getRequest - let request = rq - { HTTP.method = "POST" - , queryString = renderSimpleQuery False - [ ("privatekey", privatekey) - , ("remoteip", remoteip) - , ("challenge", challenge) - , ("response", response) - ] - } - result <- liftIO $ Control.Exception.try $ runResourceT $ httpLbs request man - case result of - Left e -> do return (ConnectionError (e :: HttpException)) - Right r -> do let ls = BSL.split 0x0a $ responseBody r - let ua = return (Failure $ responseBody r) - if length ls < 2 - then ua - else case ls !! 0 of - "true" -> return $ Success - "false" -> return $ Failure (ls !! 1) - _ -> ua - _ -> return MissingArguments +-- See 'ReCaptchaResult' for possible failure types. +-- +-- @ +-- cstate <- getCaptcha +-- case cstate of +-- Success -> writeText "Congratulations! You won." +-- Failure -> writeText "Incorrect cstate answer." +-- MissingResponseParam -> writeText "No g-recaptcha-response in POST" +-- InvalidServerResponse -> writeText "Did Google change their API?" +-- Errors errs -> writeText ("Errors: " <> 'T.pack' ('show' errs)) +-- @ +-- +-- This may throw a 'HTTP.HttpException' if there is a connection-related error. +getCaptcha :: HasReCaptcha b => Handler b c Captcha +getCaptcha = do + mresponse <- getPostParam "g-recaptcha-response" + case mresponse of + Just answer -> withTop' captchaLens $ do + manager <- gets connectionManager + getQuery <- gets recaptchaQuery + remoteip <- getsRequest rqRemoteAddr + response <- runReaderT (HTTP.httpLbs (getQuery remoteip answer)) manager + -- The reply is a JSON object looking like + -- { + -- "success": true|false, + -- "error-codes": [...] // optional + -- } + -- see + -- we just use aeson and the derived FromJSON instance here + return $! case JSON.decode (HTTP.responseBody response) of + Just obj + | success obj -> Success + | invalidInput obj -> Failure + | otherwise -> Errors (fold (error_codes obj)) + Nothing -> InvalidServerResponse + Nothing -> return MissingResponseParam + where + invalidInput obj = error_codes obj == Just ["invalid-input-response"] +-- | Run one of two handlers on either failing or succeeding a captcha. +-- +-- @ +-- 'withCaptcha' banForever $ do +-- postId <- 'getParam' "id" +-- thing <- 'getPostParam' thing +-- addCommentToDB postId thing +-- @ +-- +-- See 'getCaptcha' +withCaptcha + :: HasReCaptcha b + => Handler b c () -- ^ Ran on failure + -> Handler b c () -- ^ Ran on success + -> Handler b c () +withCaptcha onFail onSuccess = do + s <- getCaptcha + withTop' captchaLens (cstate .= s) + case s of + Success -> onSuccess + _ -> onFail + +-- | 'pass' if the cstate failed. Logs errors (not incorrect captchas) with +-- 'logError'. +-- +-- @ 'checkCaptcha' '<|>' 'writeText' "Captcha failed!" @ +-- +-- See 'getCaptcha' +checkCaptcha :: HasReCaptcha b => Handler b c () +checkCaptcha = do + s <- getCaptcha + withTop' captchaLens (cstate .= s) + case s of + Success -> return () + Failure -> pass + someError -> do + logError =<< errorMsg (BS.pack (show someError)) + pass + +errorMsg :: (MonadSnaplet m, Monad (m b v)) => BS.ByteString + -> m b v BS.ByteString +errorMsg err = do + ancestry <- getSnapletAncestry + name <- getSnapletName + return $! showTextList (ancestry++toList name) <> " (ReCaptcha) : " <> err + where + showTextList :: [Text] -> BS.ByteString + showTextList = BS.intercalate "/" . map encodeUtf8 diff --git a/src/Snap/Snaplet/ReCaptcha/Example.hs b/src/Snap/Snaplet/ReCaptcha/Example.hs new file mode 100644 --- /dev/null +++ b/src/Snap/Snaplet/ReCaptcha/Example.hs @@ -0,0 +1,150 @@ +{-# LANGUAGE FlexibleInstances #-} +{-# LANGUAGE MultiParamTypeClasses #-} +{-# LANGUAGE OverloadedStrings #-} +{-# LANGUAGE ScopedTypeVariables #-} +{-# LANGUAGE TemplateHaskell #-} +module Snap.Snaplet.ReCaptcha.Example + ( -- * Main + main + , initSample + -- * Necessities + , sampleTemplate + -- * Implementation + , initBlog + ) where +import qualified Blaze.ByteString.Builder as Blaze +import Heist +import Heist.Compiled + +import Snap +import Snap.Snaplet.Heist.Compiled +import Snap.Snaplet.ReCaptcha + +import Control.Lens + +import qualified Data.ByteString.Char8 as BS +import Data.Monoid +import Data.Text (Text) + +-- | Simple sample snaplet, built using 'ReCaptcha' in order to demonstrate how +-- one might use it in the scenario of adding comments to a blog. +data Sample = Sample + { _recaptcha :: !(Snaplet ReCaptcha) + , _heist :: !(Snaplet (Heist Sample)) + , _blog :: !(Snaplet Blog) + } + +-- | Not actually a blog +data Blog = Blog + { _currentPost :: !(Maybe BS.ByteString) + } + +makeLenses ''Sample +makeLenses ''Blog + +instance HasReCaptcha Sample where + captchaLens = subSnaplet recaptcha + +instance HasHeist Sample where + heistLens = subSnaplet heist + +-- | A "blog" snaplet which reads hypothetical "posts" by their 'id', routing +-- GET on \/posts\/:id to display a post, and POST on \/posts\/:id to add a +-- comment to them. For loose, useless definitions of "post" and "comment" - +-- this snaplet is only for demonstration purposes. +initBlog :: forall b. (HasReCaptcha b, HasHeist b) => Snaplet (Heist b) + -> SnapletInit b Blog +initBlog heist = makeSnaplet "blog" "simple blog" Nothing $ do + me <- getLens + + addRoutes + -- Hypothetical comments are just sent as POST to the respective post they + -- are replying to + [("/posts/:id", method GET displayPost <|> method POST commentOnPost)] + + addConfig heist $ mempty &~ do + -- Just 'blog-post' to be whatever is in 'post' at the time + -- (hopefully set by 'displayPost' after being routed to /posts/:id) + scCompiledSplices .= + ("blog-post" ## pureSplice Blaze.fromByteString . lift $ do + post' <- withTop' me (use currentPost) + case post' of + Just post -> return post + Nothing -> fail "Couldn't find that.") + + return (Blog Nothing) + where + displayPost :: Handler b Blog () + displayPost = do + Just postId <- getParam "id" + currentPost .= Just ("there is no post #" <> postId <> ". only me.") + render "recaptcha-example" <|> fail "Couldn't load recaptcha-example.tpl" + + commentOnPost :: Handler b Blog () + commentOnPost = do + Just postId <- getParam "id" + Just captcha <- getPostParam "g-recaptcha-response" + checkCaptcha <|> fail "Bad captcha response." + -- if we reach here, the captcha was OK + Just name <- getPostParam "name" + Just email <- getPostParam "email" + Just content <- getPostParam "content" + writeBS $ BS.concat [postId, " < (", name,", ", email, ", ", content, ")"] + +-- | Heist template, written to $PWD\/snaplets\/heist\/recaptcha-example.tpl +-- +-- >sampleTemplate ≈ +-- > +-- > +-- > +-- > +-- > +-- >
+-- > +-- > +-- >
+-- > +-- >
+-- > +-- > +-- > +-- > +-- > +-- +sampleTemplate :: Text +sampleTemplate = + "\ + \ \ + \ \ + \ \ + \ \ + \
\ + \ \ + \ \ + \
\ + \ \ + \
\ + \ \ + \ \ + \ \ + \ \ + \" + +-- | Requires 'snaplets/heist/templates/sample.tpl' - a suggested version of which +-- is available in this module as 'sampleTemplate'. +-- +-- This simple asks for your site and private key through stdin. +initSample :: SnapletInit Sample Sample +initSample = makeSnaplet "sample" "" Nothing $ do + h <- nestSnaplet "heist" heist (heistInit "templates") + c <- nestSnaplet "submit" recaptcha (initReCaptcha (Just h)) + t <- nestSnaplet "blog" blog (initBlog h) + return (Sample c h t) + +-- | @ 'main' = 'serveSnaplet' 'defaultConfig' 'initSample' @ +-- +-- You can load this into GHCi and run it, with full logging to stdout/stderr +-- +-- >>> :main --verbose --access-log= --error-log= +main :: IO () +main = serveSnaplet defaultConfig initSample diff --git a/src/recaptcha-test.hs b/src/recaptcha-test.hs deleted file mode 100644 --- a/src/recaptcha-test.hs +++ /dev/null @@ -1,68 +0,0 @@ -{-# LANGUAGE OverloadedStrings, FlexibleInstances, MultiParamTypeClasses, TemplateHaskell #-} -module Main where - -import Data.Lens.Common -import Data.Lens.Template - -import qualified Data.ByteString as BS -import qualified Data.ByteString.Lazy as BSL -import qualified Data.Text as T -import qualified Data.Text.Encoding as T -import Text.Blaze.Html5 as H -import Text.Blaze.Html5.Attributes as A -import Data.Monoid -import Control.Applicative -import Text.Blaze.Renderer.Utf8 (renderHtml) - -import Snap -import Snap.Snaplet.ReCaptcha - -data ReCaptchaTest - = ReCaptchaTest - { _recaptcha :: Snaplet ReCaptcha - } - -$(makeLenses [''ReCaptchaTest]) - -instance HasReCaptcha ReCaptchaTest where - recaptchaLens = subSnaplet recaptcha - -main :: IO () -main - = do putStrLn "Please enter your ReCaptcha public key:" - puk <- getLine - putStrLn "Please enter your ReCaptcha private key:" - prk <- T.encodeUtf8 <$> T.pack <$> getLine - putStrLn "Now point your browser to localhost:8000!" - serveSnaplet defaultConfig (snaplet puk prk) - where - snaplet puk prk - = makeSnaplet - "ReCaptchaTest" - "" - Nothing - $ do r <- embedSnaplet "recaptcha" recaptcha $ initReCaptcha prk - addRoutes [("", writeLBS $ renderHtml $ template puk) - ,("verify", do r <- verifyCaptcha - case r of - Success -> writeBS "Success." - Failure x -> writeBS "Failure: " >> writeLBS x - ConnectionError x -> writeBS "ConnectionError: " >> writeText (T.pack $ show x) - MissingArguments -> writeBS "MissingArguments" - ) - ] - return (ReCaptchaTest r) - template puk - = H.docTypeHtml - $ do H.head - $ do H.script "" - ! A.type_ "text/javascript" - ! A.src "http://www.google.com/recaptcha/api/js/recaptcha_ajax.js" - H.body - ! A.onload ( "Recaptcha.create('" `mappend` toValue puk `mappend` "', 'recaptcha');" ) - $ do H.form - ! A.action "verify" - ! A.method "POST" - $ do H.div "" - ! A.id "recaptcha" - H.button "Test"