Add 4chan posting

1 files changed, 160 insertions, 0 deletions

diff --git a/src/GoogleCaptcha.cpp b/src/GoogleCaptcha.cpp
new file mode 100644
index 0000000..b5c3e3c
--- /dev/null
+++ b/src/GoogleCaptcha.cpp
@@ -0,0 +1,160 @@
+#include "../include/GoogleCaptcha.hpp"
+#include "../include/StringUtils.hpp"
+#include "../include/DownloadUtils.hpp"
+
+namespace QuickMedia {
+    static bool google_captcha_response_extract_id(const std::string& html, std::string& result)
+    {
+        size_t value_index = html.find("value=\"");
+        if(value_index == std::string::npos)
+            return false;
+
+        size_t value_begin = value_index + 7;
+        size_t value_end = html.find('"', value_begin);
+        if(value_end == std::string::npos)
+            return false;
+
+        size_t value_length = value_end - value_begin;
+        // The id is also only valid if it's in base64, but it might be overkill to verify if it's base64 here
+        if(value_length < 300)
+            return false;
+
+        result = html.substr(value_begin, value_length);
+        return true;
+    }
+
+    static bool google_captcha_response_extract_goal_description(const std::string& html, std::string& result)
+    {
+        size_t goal_description_begin = html.find("rc-imageselect-desc-no-canonical");
+        if(goal_description_begin == std::string::npos) {
+            goal_description_begin = html.find("rc-imageselect-desc");
+            if(goal_description_begin == std::string::npos)
+                return false;
+        }
+
+        goal_description_begin = html.find('>', goal_description_begin);
+        if(goal_description_begin == std::string::npos)
+            return false;
+
+        goal_description_begin += 1;
+
+        size_t goal_description_end = html.find("</div", goal_description_begin);
+        if(goal_description_end == std::string::npos)
+            return false;
+
+        // The goal description with google captcha right now is "Select all images with <strong>subject</strong>".
+        // TODO: Should the subject be extracted, so bold styling can be applied to it?
+        result = html.substr(goal_description_begin, goal_description_end - goal_description_begin);
+        string_replace_all(result, "<strong>", "");
+        string_replace_all(result, "</strong>", "");
+        return true;
+    }
+
+    static std::optional<GoogleCaptchaChallengeInfo> google_captcha_parse_request_challenge_response(const std::string& api_key, const std::string& html_source)
+    {
+        GoogleCaptchaChallengeInfo result;
+        if(!google_captcha_response_extract_id(html_source, result.id))
+            return std::nullopt;
+        result.payload_url = "https://www.google.com/recaptcha/api2/payload?c=" + result.id + "&k=" + api_key;
+        if(!google_captcha_response_extract_goal_description(html_source, result.description))
+            return std::nullopt;
+        return result;
+    }
+
+    // Note: This assumes strings (quoted data) in html tags dont contain '<' or '>'
+    static std::string strip_html_tags(const std::string& text)
+    {
+        std::string result;
+        size_t index = 0;
+        while(true)
+        {
+            size_t tag_start_index = text.find('<', index);
+            if(tag_start_index == std::string::npos)
+            {
+                result.append(text.begin() + index, text.end());
+                break;
+            }
+
+            result.append(text.begin() + index, text.begin() + tag_start_index);
+            
+            size_t tag_end_index = text.find('>', tag_start_index + 1);
+            if(tag_end_index == std::string::npos)
+                break;
+            index = tag_end_index + 1;
+        }
+        return result;
+    }
+
+    static std::optional<std::string> google_captcha_parse_submit_solution_response(const std::string& html_source)
+    {
+        size_t start_index = html_source.find("\"fbc-verification-token\">");
+        if(start_index == std::string::npos)
+            return std::nullopt;
+
+        start_index += 25;
+        size_t end_index = html_source.find("</", start_index);
+        if(end_index == std::string::npos)
+            return std::nullopt;
+
+        return strip_html_tags(html_source.substr(start_index, end_index - start_index));
+    }
+
+    std::future<bool> google_captcha_request_challenge(const std::string &api_key, const std::string &referer, RequestChallengeResponse challenge_response_callback, bool use_tor) {
+        return std::async(std::launch::async, [challenge_response_callback, api_key, referer, use_tor]() {
+            std::string captcha_url = "https://www.google.com/recaptcha/api/fallback?k=" + api_key;
+            std::string response;
+            std::vector<CommandArg> additional_args = {
+                CommandArg{"-H", "Referer: " + referer}
+            };
+            DownloadResult download_result = download_to_string(captcha_url, response, additional_args, use_tor);
+            if(download_result == DownloadResult::OK) {
+                //fprintf(stderr, "Failed  to get captcha, response: %s\n", response.c_str());
+                challenge_response_callback(google_captcha_parse_request_challenge_response(api_key, response));
+                return true;
+            } else {
+                fprintf(stderr, "Failed  to get captcha, response: %s\n", response.c_str());
+                challenge_response_callback(std::nullopt);
+                return false;
+            }
+        });
+    }
+
+    static std::string build_post_solution_response(std::array<bool, 9> selected_images) {
+        std::string result;
+        for(size_t i = 0; i < selected_images.size(); ++i) {
+            if(selected_images[i]) {
+                if(!result.empty())
+                    result += "&";
+                result += "response=" + std::to_string(i);
+            }
+        }
+        return result;
+    }
+
+    std::future<bool> google_captcha_post_solution(const std::string &api_key, const std::string &captcha_id, std::array<bool, 9> selected_images, PostSolutionResponse solution_response_callback, bool use_tor) {
+        return std::async(std::launch::async, [solution_response_callback, api_key, captcha_id, selected_images, use_tor]() {
+            std::string captcha_url = "https://www.google.com/recaptcha/api/fallback?k=" + api_key;
+            std::string response;
+            std::vector<CommandArg> additional_args = {
+                CommandArg{"-H", "Referer: " + captcha_url},
+                CommandArg{"--data", "c=" + captcha_id + "&" + build_post_solution_response(selected_images)}
+            };
+            DownloadResult post_result = download_to_string(captcha_url, response, additional_args, use_tor);
+            if(post_result == DownloadResult::OK) {
+                //fprintf(stderr, "Failed  to post captcha solution, response: %s\n", response.c_str());
+                std::optional<std::string> captcha_post_id = google_captcha_parse_submit_solution_response(response);
+                if(captcha_post_id) {
+                    solution_response_callback(std::move(captcha_post_id), std::nullopt);
+                } else {
+                    std::optional<GoogleCaptchaChallengeInfo> challenge_info = google_captcha_parse_request_challenge_response(api_key, response);
+                    solution_response_callback(std::nullopt, std::move(challenge_info));
+                }
+                return true;
+            } else {
+                fprintf(stderr, "Failed  to post captcha solution, response: %s\n", response.c_str());
+                solution_response_callback(std::nullopt, std::nullopt);
+                return false;
+            }
+        });
+    }
+}
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