1/* Part of SWI-Prolog 2 3 Author: Jan Wielemaker 4 E-mail: J.Wielemaker@vu.nl 5 WWW: http://www.swi-prolog.org 6 Copyright (C): 2013-2018, VU University Amsterdam 7 CWI, Amsterdam 8 9 This program is free software; you can redistribute it and/or 10 modify it under the terms of the GNU General Public License 11 as published by the Free Software Foundation; either version 2 12 of the License, or (at your option) any later version. 13 14 This program is distributed in the hope that it will be useful, 15 but WITHOUT ANY WARRANTY; without even the implied warranty of 16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 GNU General Public License for more details. 18 19 You should have received a copy of the GNU General Public 20 License along with this library; if not, write to the Free Software 21 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 22 23 As a special exception, if you link this library with other files, 24 compiled with a Free Software compiler, to produce an executable, this 25 library does not by itself cause the resulting executable to be covered 26 by the GNU General Public License. This exception does not however 27 invalidate any other reasons why the executable file might be covered by 28 the GNU General Public License. 29*/ 30 31:- module(recaptcha, 32 [ recaptcha//1, % +Options 33 recaptcha_parameters/1, % -HTTP parameter list 34 recaptcha_verify/2 % +Request, +HTTPParamList 35 ]). 36:- use_module(library(http/html_write)). 37:- use_module(library(http/http_open)). 38:- use_module(library(option)). 39:- use_module(library(debug)). 40:- use_module(library(http/json)).
78:- multifile 79 key/2. 80 81test_key(public, '6LeIxAcTAAAAAJcZVRqyHh71UMIEGNQ_MXjiZKhI'). 82test_key(private, '6LeIxAcTAAAAAGG-vFI1TnRWxMZNFuojJ4WifJWe').
clean.
95recaptcha(Options) -->
96 { ( key(public, PublicKey)
97 -> true
98 ; test_key(public, PublicKey)
99 ),
100 option(theme(Theme), Options, clean)
101 },
102 html_post(head, script([src('https://www.google.com/recaptcha/api.js'),
103 async(async),
104 defer(defer)
105 ], [])),
106 html(div([ class('g-recaptcha'),
107 'data-theme'(Theme),
108 'data-sitekey'(PublicKey)
109 ], [])).
116recaptcha_parameters(
117 [ 'g-recaptcha-response'(_Response, [])
118 ]).132recaptcha_verify(Request, Parameters) :- 133 memberchk('g-recaptcha-response'(Response, _), Parameters), 134 remote_IP(Request, Peer), 135 ( key(private, PrivateKey) 136 -> true 137 ; test_key(private, PrivateKey) 138 ), 139 debug(recaptcha, 'Verify: response ~p for IP ~p', [Response, Peer]), 140 setup_call_cleanup( 141 http_open('https://www.google.com/recaptcha/api/siteverify', 142 In, 143 [ post(form([ secret(PrivateKey), 144 remoteip(Peer), 145 response(Response) 146 ])) 147 ]), 148 json_read_dict(In, Dict), 149 close(In)), 150 debug(recaptcha, 'Recaptcha verify: ~p', [Dict]), 151 ( is_dict(Dict, _), 152 Dict.get(success) == true 153 -> true 154 ; is_dict(Dict, _), 155 Dict.get(success) == false 156 -> fail 157 ; throw(error(recaptcha_error(Dict), _)) 158 ). 159 160 161remote_IP(Request, IP) :- 162 memberchk(x_forwarded_for(IP0), Request), !, 163 atomic_list_concat(Parts, ', ', IP0), 164 last(Parts, IP). 165remote_IP(Request, IP) :- 166 memberchk(peer(Peer), Request), !, 167 peer_to_ip(Peer, IP). 168remote_IP(_, -). 169 170 171peer_to_ip(ip(A,B,C,D), IP) :- 172 atomic_list_concat([A,B,C,D], '.', IP).
public and to the reCAPTCHA private key if Which is private.
We leave the key handling to a hook to accomodate different ways for storing and transferring the keys. A simple implementation is:
:- use_module(library(http/recaptcha)). :- multifile recaptcha:key/2. recaptcha:key(public, 'Public key goes here'). recaptcha:key(private, 'Private key goes here').
When missing, a reserved test key pair is used.
Add reCAPTCHA functionality to a form
This module is a plugin for the SWI-Prolog HTTP/HTML framework to add reCAPTCHA functionality to a form. It works as follows:
method('POST')and include, in addition to the data you request from the human user, the reCAPTCHA widget using e.g.,process_recaptcha_form(Request) :- recaptcha_parameters(RecapthaParams), http_parameters(Recaptha, [ name(Name, []), age(Age, []), ... | RecapthaParams ]), ( recaptcha_verify(Request, RecapthaParams) -> <process normal user fields> ; <you are not human> ).examples/demo.plcontains a fully functional demo.