Add URL utility

CMakeLists.txt

@@ -23,7 +23,7 @@ list(APPEND FLAGS -Werror -Wall -Wextra -Wshadow -Wpedantic -Wno-gnu-anonymous-s
 add_link_options(${FLAGS})
 
 
-add_executable(${PROJECT_NAME} main.cpp misc.cpp config.cpp servehelper.cpp pixivclient.cpp blankie/serializer.cpp blankie/escape.cpp
+add_executable(${PROJECT_NAME} main.cpp misc.cpp config.cpp servehelper.cpp pixivclient.cpp blankie/serializer.cpp blankie/escape.cpp blankie/murl.cpp
     routes/home.cpp routes/css.cpp routes/users/common.cpp routes/users/users.cpp)
 set_target_properties(${PROJECT_NAME}
     PROPERTIES

blankie/murl.cpp

@@ -0,0 +1,151 @@
+#include <regex>
+#include <vector>
+#include <climits>
+
+#include "murl.h"
+
+#define UNRESERVED "[\\w\\d\\-._~]"
+#define PCT_ENCODED "%[\\da-f]{2}"
+// A space is added to sub-delims to make it work with URLs that have a space
+#define SUB_DELIMS "[!$&'()*+,;= ]"
+
+#define USERINFO "((?:" UNRESERVED "|" PCT_ENCODED "|" SUB_DELIMS "|:)*)"
+// A lot looser than RFC 3986, but things will go very wrong very quickly if I comply
+#define HOST "([^/?#]+?)"
+#define PORT "(\\d*)"
+#define AUTHORITY "(?:" USERINFO "@)?" HOST "(?::" PORT ")?"
+
+#define PCHAR "(?:" UNRESERVED "|" PCT_ENCODED "|" SUB_DELIMS "|[:@])"
+#define SEGMENT PCHAR "*"
+#define PATH_ABEMPTY "((?:/" SEGMENT ")*)"
+
+#define QUERY "((?:" PCHAR "|[/?])*)"
+// Looser than RFC 3986, but fragments might as well own everything
+#define FRAGMENT "(.*)"
+
+#define HTTP_HTTPS_URL \
+    "(?:(https?)?:)?(?://" AUTHORITY ")?" \
+    PATH_ABEMPTY \
+    "(?:\\?" QUERY ")?" \
+    "(?:#" FRAGMENT ")?"
+
+static std::regex url_regex(HTTP_HTTPS_URL, std::regex::icase);
+static inline int to_int(const std::string& str);
+static void handle_segment(std::vector<std::string>& segments, const std::string& str, size_t offset, size_t length);
+
+namespace blankie {
+namespace murl {
+
+Url::Url(const std::string& str) {
+    std::smatch sm;
+    if (!std::regex_match(str, sm, url_regex)) {
+        throw std::invalid_argument(str + " is not a URL");
+    }
+    this->scheme = sm.str(1);
+    this->userinfo = sm.str(2);
+    this->hostname = sm.str(3);
+    this->port = sm[4].length() > 0 ? to_int(sm.str(4)) : -1;
+    this->path = sm.str(5);
+    this->query = sm.str(6);
+    this->fragment = sm.str(7);
+}
+
+std::string Url::to_string() const {
+    std::string str;
+    if (!this->hostname.empty()) {
+        if (!this->scheme.empty()) {
+            str += this->scheme + ':';
+        }
+        str += "//";
+        if (!this->userinfo.empty()) {
+            str += this->userinfo + '@';
+        }
+        str += this->hostname;
+        if (this->port != -1) {
+            str += ':';
+            str += std::to_string(this->port);
+        }
+    }
+    str += this->path;
+    if (!this->query.empty()) {
+        str += '?';
+        str += this->query;
+    }
+    if (!this->fragment.empty()) {
+        str += '#';
+        str += this->fragment;
+    }
+    return str;
+}
+
+std::string normalize_path(const std::string& str) {
+    std::vector<std::string> segments;
+    std::string res;
+    size_t pos = 0;
+    size_t last_pos = 0;
+    bool starts_with_slash = false;
+    bool ends_with_slash = false;
+
+    if (str.size() > 0 && str[0] == '/') {
+        starts_with_slash = true;
+        last_pos = pos = 1;
+    }
+
+    while ((pos = str.find('/', pos)) != std::string::npos) {
+        handle_segment(segments, str, last_pos, pos - last_pos);
+        last_pos = ++pos;
+    }
+    if (str.size() > last_pos) {
+        handle_segment(segments, str, last_pos, str.size() - last_pos);
+    }
+
+    if (str.size() > 1 && str.back() == '/' && !segments.empty()) {
+        ends_with_slash = true;
+    }
+
+    if (starts_with_slash) {
+        res += '/';
+    }
+    for (size_t i = 0; i < segments.size(); i++) {
+        if (i != 0) {
+            res += '/';
+        }
+        res += std::move(segments[i]);
+    }
+    if (ends_with_slash) {
+        res += '/';
+    }
+
+    return res;
+}
+
+}; // namespace murl
+}; // namespace blankie
+
+static inline int to_int(const std::string& str) {
+    char* endptr;
+
+    long res = strtol(str.c_str(), &endptr, 10);
+    if (res > INT_MAX) {
+        throw std::overflow_error(str + " is too big");
+    } else if (res < INT_MIN) {
+        throw std::underflow_error(str + " is too small");
+    } else if (endptr[0] != '\0') {
+        throw std::invalid_argument(str + " has trailing text");
+    }
+
+    return static_cast<int>(res);
+}
+
+static void handle_segment(std::vector<std::string>& segments, const std::string& str, size_t offset, size_t length) {
+    if (length == 2 && str[offset] == '.' && str[offset + 1] == '.') {
+        if (segments.empty()) {
+            return;
+        }
+        segments.pop_back();
+    } else if (length == 1 && str[offset] == '.') {
+        // do nothing
+    } else if (length != 0) {
+        segments.push_back(str.substr(offset, length));
+    }
+}

blankie/murl.h

@@ -0,0 +1,38 @@
+#pragma once
+
+#include <string>
+
+namespace blankie {
+namespace murl {
+
+struct Url {
+    std::string scheme;
+    std::string userinfo;
+    std::string hostname;
+    int port; // -1 if unspecified
+    std::string path;
+    std::string query;
+    std::string fragment;
+
+    Url(const std::string& str);
+
+    constexpr std::string get_origin() const {
+        std::string res;
+        if (!this->scheme.empty()) {
+            res = this->scheme + "://";
+        }
+        res += this->hostname;
+        if (this->port != -1) {
+            res += ':';
+            res += std::to_string(this->port);
+        }
+        return res;
+    }
+
+    std::string to_string() const;
+};
+
+std::string normalize_path(const std::string& str);
+
+}; // namespace murl
+}; // namespace blankie

config.cpp

@@ -16,5 +16,5 @@ void from_json(const nlohmann::json& j, Config& config) {
     if (config.bind_port < 0) {
         throw std::invalid_argument("Invalid port to bind to: "s + std::to_string(config.bind_port));
     }
-    j.at("image_proxy_url").get_to(config.image_proxy_url);
+    config.image_proxy_url = j.at("image_proxy_url").get<std::string>();
 }

config.h

@@ -2,11 +2,12 @@
 
 #include <string>
 #include <nlohmann/json.hpp>
+#include "blankie/murl.h"
 
 struct Config {
     std::string bind_host = "127.0.0.1";
     int bind_port = 8080;
-    std::string image_proxy_url = "https://i.pixiv.cat";
+    blankie::murl::Url image_proxy_url{"https://i.pixiv.cat"};
 };
 
 Config load_config(const char* path);

pixivclient.cpp

@@ -1,10 +1,11 @@
 #include <regex>
 
+#include "blankie/murl.h"
 #include "pixivclient.h"
 
-static inline std::optional<std::string> get_1920x960_cover_image(const std::string& thumbnail);
-static inline std::optional<std::string> get_original_cover_image(const std::string& thumbnail);
-static inline std::optional<std::string> get_original_profile_picture(const std::string& thumbnail);
+static inline std::optional<std::string> get_1920x960_cover_image(blankie::murl::Url url);
+static inline std::optional<std::string> get_original_cover_image(blankie::murl::Url url);
+static inline std::optional<std::string> get_original_profile_picture(blankie::murl::Url url);
 static inline uint64_t to_ull(const std::string& str);
 
 PixivClient::PixivClient() {
@@ -81,43 +82,37 @@ void from_json(const nlohmann::json& j, User& user) {
     add_social_as_needed("pawoo", "Pawoo");
 }
 
-static std::regex c1920x960_cover_image_thumbnail_regex(
-    "((?:https?://)?(?:i\\.pximg\\.net)?)" // optional scheme and host
-    "/c/(\\d+x\\d+)(.+)"
-);
-static inline std::optional<std::string> get_1920x960_cover_image(const std::string& thumbnail) {
+static std::regex resolution_path_regex("/c/(\\d+x\\d+)(.+)");
+static inline std::optional<std::string> get_1920x960_cover_image(blankie::murl::Url url) {
     std::smatch sm;
-    if (!std::regex_match(thumbnail, sm, c1920x960_cover_image_thumbnail_regex)) {
+    if (!std::regex_match(url.path, sm, resolution_path_regex)) {
         return std::nullopt;
     }
-    if (sm[2] == "1920x960") {
+    if (sm[1] == "1920x960") {
         return std::nullopt;
     }
-    return sm[1].str() + "/c/1920x960" + sm[3].str();
+    url.path = "/c/1920x960" + sm.str(2);
+    return url.to_string();
 }
 
-static std::regex original_cover_image_thumbnail_regex(
-    "((?:https?://)?(?:i\\.pximg\\.net)?)" // optional scheme and host
-    "/c/[0-9a-z_-]+(/.+)_master\\d+(\\.\\w{3,4})"
-);
-static inline std::optional<std::string> get_original_cover_image(const std::string& thumbnail) {
+static std::regex thumbnail_path_regex("/c/[^/]+/(.+)_master\\d+(\\.\\w{3,4})?");
+static inline std::optional<std::string> get_original_cover_image(blankie::murl::Url url) {
     std::smatch sm;
-    if (!std::regex_match(thumbnail, sm, original_cover_image_thumbnail_regex)) {
+    if (!std::regex_match(url.path, sm, thumbnail_path_regex)) {
         return std::nullopt;
     }
-    return sm[1].str() + sm[2].str() + sm[3].str();
+    url.path = sm.str(1) + sm.str(2);
+    return url.to_string();
 }
 
-static std::regex profile_picture_thumbnail_regex(
-    "((?:https?://)?(?:i\\.pximg\\.net)?)" // optional scheme and host
-    "(/.+)_\\d+(\\.\\w{3,4})"
-);
-static inline std::optional<std::string> get_original_profile_picture(const std::string& thumbnail) {
+static std::regex profile_picture_thumbnail_path_regex("(/.+)_\\d{2,}(\\.\\w{3,4})");
+static inline std::optional<std::string> get_original_profile_picture(blankie::murl::Url url) {
     std::smatch sm;
-    if (!std::regex_match(thumbnail, sm, profile_picture_thumbnail_regex)) {
+    if (!std::regex_match(url.path, sm, profile_picture_thumbnail_path_regex)) {
         return std::nullopt;
     }
-    return sm[1].str() + sm[2].str() + sm[3].str();
+    url.path = sm.str(1) + sm.str(2);
+    return url.to_string();
 }
 
 static inline uint64_t to_ull(const std::string& str) {

routes/users/common.cpp

@@ -8,20 +8,20 @@ static std::string thumbnail_or_original(const Images& images);
 static std::string original_or_thumbnail(const Images& images);
 
 Element generate_user_header(const User& user, const Config& config) {
-    auto proxy_url = [&](std::string url) {
-        return config.image_proxy_url + remove_origin(std::move(url));
-    };
-
     Element header("header");
     if (user.cover_images) {
-        header.nodes.push_back(Element("a", {{"href", proxy_url(original_or_thumbnail(*user.cover_images))}}, {
-            Element("img", {{"class", "cover"}, {"src", proxy_url(thumbnail_or_original(*user.cover_images))}}, {})
+        std::string cover_original = proxy_image_url(config, original_or_thumbnail(*user.cover_images));
+        std::string cover_thumbnail = proxy_image_url(config, thumbnail_or_original(*user.cover_images));
+        header.nodes.push_back(Element("a", {{"href", std::move(cover_original)}}, {
+            Element("img", {{"class", "cover"}, {"src", std::move(cover_thumbnail)}}, {})
         }));
     }
 
+    std::string profile_picture_original = proxy_image_url(config, original_or_thumbnail(user.profile_pictures));
+    std::string profile_picture_thumbnail = proxy_image_url(config, thumbnail_or_original(user.profile_pictures));
     header.nodes.push_back(Element("div", {{"class", "usermetadata"}}, {
-        Element("a", {{"href", proxy_url(original_or_thumbnail(user.profile_pictures))}}, {
-            Element("img", {{"class", "profilepicture"}, {"src", proxy_url(thumbnail_or_original(user.profile_pictures))}}, {})
+        Element("a", {{"href", std::move(profile_picture_original)}}, {
+            Element("img", {{"class", "profilepicture"}, {"src", std::move(profile_picture_thumbnail)}}, {})
         }),
         Element("div", {
             Element("p", {Element("b", {user.display_name}), " (@", user.username, ")"}),

servehelper.cpp

@@ -3,15 +3,12 @@
 #include "config.h"
 #include "servehelper.h"
 
-static inline std::string get_image_proxy_origin(const std::string& url);
-
 void serve(const httplib::Request& req, httplib::Response& res, const Config& config, std::string title, Element element) {
     using namespace std::string_literals;
 
-    std::string origin = get_origin(req, config);
-    std::string css_url = origin + "/style.css";
+    std::string css_url = get_origin(req, config) + "/style.css";
     res.set_header("Content-Security-Policy", "default-src 'none'; style-src "s + css_url
-        + "; img-src " + get_image_proxy_origin(config.image_proxy_url));
+        + "; img-src " + config.image_proxy_url.get_origin());
 
     Element html("html", {
         Element("head", {
@@ -74,29 +71,16 @@ std::string get_origin(const httplib::Request& req, const Config& config) {
     return origin;
 }
 
-static std::regex remove_origin_regex(
-    "(?:https?://)?" // optional schema
-    "(?:.+?@)?" // optional username and pass
-    "(?:[^/]+[.:][^/]+(?:\\d+)?)" // host
-    "(/.*)");
-std::string remove_origin(const std::string& url) {
-    std::smatch sm;
-    if (!std::regex_match(url, sm, remove_origin_regex)) {
-        return url;
+std::string proxy_image_url(const Config& config, blankie::murl::Url url) {
+    blankie::murl::Url new_url = config.image_proxy_url;
+    if (!url.path.empty() && url.path[0] != '/') {
+        new_url.path += '/';
     }
-    return sm[1].str();
-}
-
-
-static std::regex image_proxy_regex(
-    "(https?://)?" // optional scheme
-    "(?:.+?@)?" // optional username and pass
-    "([^/]+(?::\\d+)?)" // host
-    "(?:/.*)?$");
-static inline std::string get_image_proxy_origin(const std::string& url) {
-    std::smatch sm;
-    if (!std::regex_match(url, sm, image_proxy_regex)) {
-        return url;
+    new_url.path += std::move(url.path);
+    if (!new_url.query.empty() && !url.query.empty()) {
+        new_url.query += '&';
+        new_url.query += std::move(url.query);
     }
-    return sm[1].str() + sm[2].str();
+    new_url.fragment = std::move(url.fragment);
+    return new_url.to_string();
 }

servehelper.h

@@ -3,6 +3,7 @@
 #include <optional>
 
 #include <httplib/httplib.h>
+#include "blankie/murl.h"
 #include "blankie/serializer.h"
 
 struct Config; // forward declaration from config.h
@@ -13,4 +14,4 @@ void serve_error(const httplib::Request& req, httplib::Response& res, const Conf
         std::string title, std::optional<std::string> subtitle = std::nullopt, std::optional<std::string> info = std::nullopt);
 void serve_redirect(const httplib::Request& req, httplib::Response& res, const Config& config, std::string url);
 std::string get_origin(const httplib::Request& req, const Config& config);
-std::string remove_origin(const std::string& url);
+std::string proxy_image_url(const Config& config, blankie::murl::Url url);