Initial commit

.gitignore

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+builddir/

CMakeLists.txt

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+cmake_minimum_required(VERSION 3.20.2)
+project(patom CXX)
+
+find_package(CURL REQUIRED)
+find_package(nlohmann_json REQUIRED)
+
+add_executable(${PROJECT_NAME} main.cpp)
+target_link_libraries(${PROJECT_NAME} PRIVATE curl nlohmann_json::nlohmann_json)

build

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+#!/bin/sh
+test "$1" = "debug" && TYPE="Debug" || TYPE="Release"
+echo "Building in $TYPE"
+cmake -S . -B builddir -D CMAKE_BUILD_TYPE=$TYPE && cd builddir && cmake --build . --config "$TYPE"

main.cpp

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+#include <cstdlib>
+#include <stdio.h>
+#include <curl/curl.h>
+#include <nlohmann/json.hpp>
+
+#define MAX_FILE_SIZE 1024 * 1024 * 1024
+#define set_curl_opt_or_die(curl, option, param) do { \
+    CURLcode curl_code = curl_easy_setopt(curl, option, param); \
+    if (curl_code != CURLE_OK) { \
+        curl_easy_cleanup(curl); \
+        fprintf(stderr, "curl_easy_setopt returned %s\n", curl_easy_strerror(curl_code)); \
+        curl_global_cleanup(); \
+        exit(1); \
+    } \
+} while(0)
+
+size_t write_memory_cb(char* contents, size_t size, size_t nmemb, std::string* str) {
+    size_t realsize = size * nmemb;
+    if (str->length() + realsize > MAX_FILE_SIZE) {
+        fprintf(stderr, "Max file size reached\n");
+        return 0;
+    }
+    str->append(contents, realsize);
+    return realsize;
+}
+
+// behold: the why
+// oh and this is stolen from https://stackoverflow.com/a/3418285
+void escape_xml(std::string str) {
+    if (str.empty()) {
+        return;
+    }
+    size_t start = 0;
+    while ((start = str.find("&", start)) != std::string::npos) {
+        str.replace(start, 1, "&amp;");
+        start += 5;
+    }
+    start = 0;
+    while ((start = str.find("<", start)) != std::string::npos) {
+        str.replace(start, 1, "&lt;");
+        start += 4;
+    }
+    start = 0;
+    while ((start = str.find(">", start)) != std::string::npos) {
+        str.replace(start, 1, "&gt;");
+        start += 4;
+    }
+    start = 0;
+    while ((start = str.find("\"", start)) != std::string::npos) {
+        str.replace(start, 1, "&quot;");
+        start += 6;
+    }
+    start = 0;
+    while ((start = str.find("'", start)) != std::string::npos) {
+        str.replace(start, 1, "&#x27;");
+        start += 6;
+    }
+}
+
+int main(int argc, char* argv[]) {
+    if (argc != 2) {
+        if (argc > 0) {
+            fprintf(stderr, "Usage: %s <pixiv user id>\n", argv[0]);
+        } else {
+            fprintf(stderr, "Usage: patom <pixiv user id>\n");
+        }
+        return 1;
+    }
+    char* pixiv_user_id = argv[1];
+    if (!*pixiv_user_id) {
+        fprintf(stderr, "User ID is empty\n");
+        return 1;
+    }
+    for (int i=0; pixiv_user_id[i]; i++) {
+        if (!(pixiv_user_id[i] >= '0' && pixiv_user_id[i] <= '9')) {
+            fprintf(stderr, "User ID is not numeric\n");
+            return 1;
+        }
+    }
+    curl_global_init(CURL_GLOBAL_ALL);
+    CURL* curl = curl_easy_init();
+    if (!curl) {
+        fprintf(stderr, "curl_easy_init returned NULL\n");
+        curl_global_cleanup();
+        return 1;
+    }
+    set_curl_opt_or_die(curl, CURLOPT_PROTOCOLS, CURLPROTO_HTTPS);
+    std::string url = "https://www.pixiv.net/touch/ajax/user/illusts?type=illust&lang=en&id=";
+    url.append(argv[1]);
+    set_curl_opt_or_die(curl, CURLOPT_URL, url.c_str());
+    std::string response_body;
+    set_curl_opt_or_die(curl, CURLOPT_WRITEFUNCTION, write_memory_cb);
+    set_curl_opt_or_die(curl, CURLOPT_WRITEDATA, &response_body);
+    CURLcode curl_code = curl_easy_perform(curl);
+    curl_easy_cleanup(curl);
+    if (curl_code != CURLE_OK) {
+        fprintf(stderr, "curl_easy_perform returned %s\n", curl_easy_strerror(curl_code));
+        curl_global_cleanup();
+        return 1;
+    }
+    curl_global_cleanup();
+    nlohmann::json j = nlohmann::json::parse(response_body);
+
+    if (j["error"].get<bool>()) {
+        fprintf(stderr, "Error returned by the API: %s\n", j["message"].get<std::string>().c_str());
+        return 1;
+    }
+    std::vector<nlohmann::json> illusts = j["body"]["illusts"].get<std::vector<nlohmann::json>>();
+    time_t last_updated_timestamp;
+    if (illusts.size()) {
+        last_updated_timestamp = illusts[0]["upload_timestamp"].get<time_t>();
+    } else {
+        last_updated_timestamp = time(NULL);
+    }
+    std::string ogp_title = j["body"]["meta"]["ogp"]["title"].get<std::string>();
+    escape_xml(ogp_title);
+    char tm_str[100] = "";
+    strftime(tm_str, 100, "%FT%TZ", gmtime(&last_updated_timestamp));
+    // wonder if pixiv is a urn namespace
+    // also cba to make another request to find the username so here we are
+    printf("<?xml version=\"1.0\"?>\n<feed xmlns=\"http://www.w3.org/2005/Atom\">\n    <id>urn:pixiv:user:%s</id>\n    <author><name>%s</name></author>\n    <updated>%s</updated>\n    <title type=\"text\">%s</title>\n", argv[1], argv[1], tm_str, ogp_title.c_str());
+    for (size_t i=0; i < illusts.size(); i++) {
+        nlohmann::json illust = illusts[i];
+        std::string title = illust["alt"].get<std::string>();
+        std::string illust_id = illust["id"].get<std::string>();
+        // istg if 0 isn't 1970
+        time_t upload_timestamp = illust["upload_timestamp"].get<time_t>();
+        strftime(tm_str, 100, "%FT%TZ", gmtime(&upload_timestamp));
+        escape_xml(title);
+        printf("    <entry>\n        <id>urn:pixiv:illust:%s</id>\n        <title type=\"text\">%s</title>\n        <updated>%s</updated>\n        <link rel=\"alternate\" type=\"text/html\" href=\"https://www.pixiv.net/en/artworks/%s\"></link>\n    </entry>\n", illust_id.c_str(), title.c_str(), tm_str, illust_id.c_str());
+    }
+    printf("</feed>\n");
+    return 0;
+}