From e5fc00e506806f06bde32e9334fdec57dd8cb86d Mon Sep 17 00:00:00 2001
From: dec05eba <dec05eba@protonmail.com>
Date: Tue, 27 Jul 2021 20:24:36 +0200
Subject: Implement new 4chan captcha

---
 src/plugins/Fourchan.cpp | 62 ++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 60 insertions(+), 2 deletions(-)

(limited to 'src/plugins/Fourchan.cpp')

diff --git a/src/plugins/Fourchan.cpp b/src/plugins/Fourchan.cpp
index d4fb726..84a0675 100644
--- a/src/plugins/Fourchan.cpp
+++ b/src/plugins/Fourchan.cpp
@@ -3,6 +3,8 @@
 #include "../../include/Storage.hpp"
 #include "../../include/StringUtils.hpp"
 #include "../../include/NetUtils.hpp"
+#include "../../include/Notification.hpp"
+#include "../../external/cppcodec/base64_rfc4648.hpp"
 #include <HtmlParser.h>
 #include <json/reader.h>
 #include <string.h>
@@ -500,7 +502,7 @@ namespace QuickMedia {
         return filepath.c_str() + index + 1;
     }
 
-    PostResult FourchanThreadPage::post_comment(const std::string &captcha_id, const std::string &comment, const std::string &filepath) {
+    PostResult FourchanThreadPage::post_comment(const std::string &captcha_id, const std::string &captcha_solution, const std::string &comment, const std::string &filepath) {
         std::string url = "https://sys.4chan.org/" + board_id + "/post";
 
         std::vector<CommandArg> additional_args = {
@@ -517,7 +519,9 @@ namespace QuickMedia {
         }
 
         if(pass_id.empty()) {
-            additional_args.push_back(CommandArg{"--form-string", "g-recaptcha-response=" + captcha_id});
+            additional_args.push_back(CommandArg{"--form-string", "t-challenge=" + captcha_id});
+            if(!captcha_solution.empty())
+                additional_args.push_back(CommandArg{"--form-string", "t-response=" + captcha_solution});
         } else {
             Path cookies_filepath;
             if(get_cookies_filepath(cookies_filepath, SERVICE_NAME) != 0) {
@@ -558,4 +562,58 @@ namespace QuickMedia {
         }
         return pass_id;
     }
+
+    static bool base64_decode(const Json::Value &json_to_decode, std::string &decoded) {
+        if(!json_to_decode.isString())
+            return false;
+
+        const char *start;
+        const char *end;
+        if(!json_to_decode.getString(&start, &end))
+            return false;
+
+        try {
+            decoded = cppcodec::base64_rfc4648::decode<std::string>(start, end - start);
+            return true;
+        } catch(std::exception&) {
+            return false;
+        }
+    }
+
+    PluginResult FourchanThreadPage::request_captcha_challenge(ImageBoardCaptchaChallenge &challenge_response) {
+        Json::Value json_root;
+        DownloadResult result = download_json(json_root, "https://sys.4chan.org/captcha?board=" + url_param_encode(board_id) + "&thread_id=" + thread_id, {}, true);
+        if(result != DownloadResult::OK) return download_result_to_plugin_result(result);
+
+        if(!json_root.isObject())
+            return PluginResult::ERR;
+
+        const Json::Value &error_json = json_root["error"];
+        if(error_json.isString()) {
+            show_notification("QuickMedia", "Failed to get captcha, error: " + error_json.asString(), Urgency::CRITICAL);
+            return PluginResult::ERR;
+        }
+
+        const Json::Value &challenge_json = json_root["challenge"];
+        const Json::Value &img_json = json_root["img"];
+        const Json::Value &bg_json = json_root["bg"];
+        const Json::Value &ttl_json = json_root["ttl"];
+        if(!challenge_json.isString() || !img_json.isString())
+            return PluginResult::ERR;
+
+        challenge_response.challenge_id = challenge_json.asString();
+
+        if(!base64_decode(img_json, challenge_response.img_data))
+            return PluginResult::ERR;
+
+        if(bg_json.isString() && !base64_decode(bg_json, challenge_response.bg_data))
+            return PluginResult::ERR;
+
+        if(ttl_json.isInt())
+            challenge_response.ttl = ttl_json.asInt();
+        else
+            challenge_response.ttl = 120;
+
+        return PluginResult::OK;
+    }
 }
\ No newline at end of file
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