Generate HTML

CMakeLists.txt

@@ -23,7 +23,8 @@ list(APPEND FLAGS -Werror -Wall -Wextra -Wshadow -Wpedantic -Wno-gnu-anonymous-s
 add_link_options(${FLAGS})
 
 
-add_executable(${PROJECT_NAME} main.cpp misc.cpp config.cpp routes/home.cpp)
+add_executable(${PROJECT_NAME} main.cpp misc.cpp config.cpp servehelper.cpp blankie/serializer.cpp blankie/escape.cpp
+    routes/home.cpp)
 set_target_properties(${PROJECT_NAME}
     PROPERTIES
         CXX_STANDARD 20

blankie/escape.cpp

@@ -0,0 +1,42 @@
+#include <stdexcept>
+
+#include "escape.h"
+
+static inline const char* get_replacement(char c);
+
+namespace blankie {
+namespace html {
+
+std::string escape(const std::string& in) {
+    std::string out;
+    size_t pos = 0;
+    size_t last_pos = 0;
+
+    out.reserve(in.size());
+    while ((pos = in.find_first_of("&<>\"'", pos)) != std::string::npos) {
+        out.append(in, last_pos, pos - last_pos);
+        out.append(get_replacement(in[pos]));
+        pos++;
+        last_pos = pos;
+    }
+
+    if (in.size() > last_pos) {
+        out.append(in, last_pos);
+    }
+
+    return out;
+}
+
+}; // namespace html
+}; // namespace blankie
+
+static inline const char* get_replacement(char c) {
+    switch (c) {
+        case '&': return "&amp;";
+        case '<': return "&lt;";
+        case '>': return "&gt;";
+        case '"': return "&quot;";
+        case '\'': return "&#x27;";
+        default: throw std::runtime_error("Encountered unknown replacement character");
+    }
+}

blankie/escape.h

@@ -0,0 +1,11 @@
+#pragma once
+
+#include <string>
+
+namespace blankie {
+namespace html {
+
+std::string escape(const std::string& in);
+
+}; // namespace html
+}; // namespace blankie

blankie/serializer.cpp

@@ -0,0 +1,54 @@
+#include <cstring>
+#include <stdexcept>
+
+#include "escape.h"
+#include "serializer.h"
+
+static inline bool should_not_close_tag(const char* tag);
+
+namespace blankie {
+namespace html {
+
+std::string Element::serialize() const {
+    std::string out;
+
+    out += '<';
+    out += this->tag;
+    for (const auto &[key, value] : this->attributes) {
+        out += ' ';
+        out += key;
+        if (!value.empty()) {
+            out += "=\"";
+            out += escape(value);
+            out += '"';
+        }
+    }
+    out += '>';
+
+    for (const Node& node : this->nodes) {
+        if (const Element* element = std::get_if<Element>(&node)) {
+            out += element->serialize();
+        } else if (const char* const* text = std::get_if<const char*>(&node)) {
+            out += escape(*text);
+        } else if (const std::string* str = std::get_if<std::string>(&node)) {
+            out += escape(*str);
+        } else {
+            throw std::runtime_error("Encountered unknown node");
+        }
+    }
+
+    if (!should_not_close_tag(this->tag)) {
+        out += "</";
+        out += this->tag;
+        out += '>';
+    }
+
+    return out;
+}
+
+}; // namespace html
+}; // namespace blankie
+
+static inline bool should_not_close_tag(const char* tag) {
+    return !strncmp(tag, "link", 5);
+}

blankie/serializer.h

@@ -0,0 +1,30 @@
+#pragma once
+
+#include <string>
+#include <vector>
+#include <variant>
+#include <utility>
+
+namespace blankie {
+namespace html {
+
+struct Element;
+
+typedef std::pair<const char*, std::string> Attribute;
+typedef std::variant<Element, const char*, std::string> Node;
+
+struct Element {
+    const char* tag;
+    std::vector<Attribute> attributes;
+    std::vector<Node> nodes;
+
+    Element(const char* tag_) : tag(tag_) {}
+    Element(const char* tag_, std::vector<Node> nodes_)
+        : tag(tag_), nodes(std::move(nodes_)) {}
+    Element(const char* tag_, std::vector<Attribute> attributes_, std::vector<Node> nodes_)
+        : tag(tag_), attributes(std::move(attributes_)), nodes(std::move(nodes_)) {}
+    std::string serialize() const;
+};
+
+}; // namespace html
+}; // namespace blankie

main.cpp

@@ -20,7 +20,9 @@ int main(int argc, char** argv) {
     }
 
     httplib::Server server;
-    server.Get("/", home_route);
+    server.Get("/", [&](const httplib::Request& req, httplib::Response& res) {
+        home_route(req, res, config);
+    });
 
     if (config.bind_port != 0) {
         if (!server.bind_to_port(config.bind_host, config.bind_port)) {

routes/home.cpp

@@ -1,5 +1,8 @@
 #include "home.h"
+#include "../servehelper.h"
 
-void home_route(const httplib::Request& req, httplib::Response& res) {
+void home_route(const httplib::Request& req, httplib::Response& res, const Config& config) {
-    res.set_content("awoo", "text/plain");
+    Element body("body");
+    body.nodes.push_back(Element("h1", {"awoo"}));
+    serve(req, res, config, "Pixwhile", std::move(body));
 }

routes/home.h

@@ -2,4 +2,6 @@
 
 #include <httplib/httplib.h>
 
-void home_route(const httplib::Request& req, httplib::Response& res);
+struct Config; // forward declaration from config.h
+
+void home_route(const httplib::Request& req, httplib::Response& res, const Config& config);

servehelper.cpp

@@ -0,0 +1,38 @@
+#include "config.h"
+#include "servehelper.h"
+
+static inline std::string get_origin(const httplib::Request& req, const Config& config);
+
+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";
+    res.set_header("Content-Security-Policy", "default-src 'none'; img-src 'self'; style-src "s + css_url);
+
+    Element html("html", {
+        Element("head", {
+            Element("title", {std::move(title)}),
+            Element("link", {{"rel", "stylesheet"}, {"href", std::move(css_url)}}, {})
+        }),
+        std::move(element)
+    });
+    res.set_content("<!DOCTYPE html>"s + html.serialize(), "text/html");
+}
+
+static inline std::string get_origin(const httplib::Request& req, const Config& config) {
+    if (req.has_header("X-Canonical-Origin")) {
+        return req.get_header_value("X-Canonical-Origin");
+    }
+
+    std::string origin = "http://";
+    if (req.has_header("Host")) {
+        origin += req.get_header_value("Host");
+    } else {
+        origin += config.bind_host;
+        if (config.bind_port != 80) {
+            origin += ':' + std::to_string(config.bind_port);
+        }
+    }
+    return origin;
+}

servehelper.h

@@ -0,0 +1,9 @@
+#pragma once
+
+#include <httplib/httplib.h>
+#include "blankie/serializer.h"
+
+struct Config; // forward declaration from config.h
+using Element = blankie::html::Element;
+
+void serve(const httplib::Request& req, httplib::Response& res, const Config& config, std::string title, Element element);