coyote/servehelper.cpp

411 lines
16 KiB
C++

#include <memory>
#include <exception>
#include <stdexcept>
#include <FastHash.h>
#include <curl/curl.h>
#include "config.h"
#include "models.h"
#include "timeutils.h"
#include "servehelper.h"
#include "lxb_wrapper.h"
#include "routes/routes.h"
#include "blankie/escape.h"
static inline void preprocess_html(const httplib::Request& req, const std::string& domain_name, const std::vector<Emoji>& emojis, lxb_dom_element_t* element);
static inline void preprocess_link(const httplib::Request& req, const std::string& domain_name, lxb_dom_element_t* element);
static inline bool should_fix_link(lxb_dom_element_t* element, const std::string& cls);
static inline lxb_dom_node_t* emojify(lxb_dom_node_t* child, const std::vector<Emoji>& emojis);
static inline std::vector<lxb_dom_node*> emojify(lxb_dom_document_t* document, std::string str, const std::vector<Emoji>& emojis);
static inline Element serialize_media(const Media& media);
class CurlUrlException : public std::exception {
public:
CurlUrlException(CURLUcode code_) : code(code_) {}
const char* what() const noexcept {
return curl_url_strerror(this->code);
}
CURLUcode code;
};
void serve(const httplib::Request& req, httplib::Response& res, std::string title, Element element, Nodes extra_head) {
using namespace std::string_literals;
std::string css_url = get_origin(req) + "/style.css";
res.set_header("Content-Security-Policy", "default-src 'none'; img-src https:; media-src https:; style-src "s + css_url);
Element head("head", {
Element("meta", {{"charset", "utf-8"}}, {}),
Element("title", {std::move(title)}),
Element("link", {{"rel", "stylesheet"}, {"href", std::move(css_url) + "?v=" + std::to_string(css_hash)}}, {}),
Element("meta", {{"name", "viewport"}, {"content", "width=device-width,initial-scale=1"}}, {})
});
head.nodes.reserve(head.nodes.size() + extra_head.size());
head.nodes.insert(head.nodes.end(), extra_head.begin(), extra_head.end());
std::string html = "<!DOCTYPE html>"s + Element("html", {
std::move(head),
std::move(element)
}).serialize();
uint64_t hash = FastHash(html.data(), html.size(), 0);
res.set_header("ETag", std::string(1, '"') + std::to_string(hash) + '"');
if (should_send_304(req, hash)) {
res.status = 304;
res.set_header("Content-Length", std::to_string(html.size()));
res.set_header("Content-Type", "text/html");
} else {
res.set_content(std::move(html), "text/html");
}
}
void serve_error(const httplib::Request& req, httplib::Response& res,
std::string title, std::optional<std::string> subtitle, std::optional<std::string> info) {
Element error_div("div", {{"class", "error"}}, {
Element("h2", {title})
});
if (subtitle) {
error_div.nodes.push_back(Element("p", {
std::move(*subtitle)
}));
}
if (info) {
error_div.nodes.push_back(Element("pre", {
Element("code", {std::move(*info)})
}));
}
Element body("body", {std::move(error_div)});
serve(req, res, std::move(title), std::move(body));
}
void serve_redirect(const httplib::Request& req, httplib::Response& res, std::string url, bool permanent) {
using namespace std::string_literals;
Element body("body", {
"Redirecting to ",
Element("a", {{"href", url}}, {url}),
""
});
res.set_redirect(url, permanent ? 301 : 302);
serve(req, res, "Redirecting to "s + std::move(url) + "", std::move(body));
}
std::string get_origin(const httplib::Request& req) {
if (req.has_header("X-Canonical-Origin")) {
return req.get_header_value("X-Canonical-Origin");
}
if (config.canonical_origin) {
return *config.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;
}
std::string proxy_mastodon_url(const httplib::Request& req, const std::string& url_str) {
using CurlStr = std::unique_ptr<char, decltype(&curl_free)>;
std::unique_ptr<CURLU, decltype(&curl_url_cleanup)> url(curl_url(), curl_url_cleanup);
if (!url) {
throw std::bad_alloc();
}
CURLUcode code = curl_url_set(url.get(), CURLUPART_URL, url_str.c_str(), 0);
if (code) {
throw CurlUrlException(code);
}
auto get_part = [&](CURLUPart part, CURLUcode ignore = CURLUE_OK) {
char* content = nullptr;
CURLUcode code = curl_url_get(url.get(), part, &content, 0);
if (code && code != ignore) {
throw CurlUrlException(code);
}
return CurlStr(content, curl_free);
};
CurlStr host = get_part(CURLUPART_HOST);
CurlStr path = get_part(CURLUPART_PATH);
CurlStr query = get_part(CURLUPART_QUERY, CURLUE_NO_QUERY);
CurlStr fragment = get_part(CURLUPART_FRAGMENT, CURLUE_NO_FRAGMENT);
std::string new_url = get_origin(req) + '/' + host.get() + path.get();
if (query) {
new_url += '?';
new_url += query.get();
}
if (fragment) {
new_url += '#';
new_url += fragment.get();
}
return new_url;
}
bool should_send_304(const httplib::Request& req, uint64_t hash) {
std::string header = req.get_header_value("If-None-Match");
if (header == "*") {
return true;
}
size_t pos = header.find(std::string(1, '"') + std::to_string(hash) + '"');
return pos != std::string::npos && (pos == 0 || header[pos - 1] != '/');
}
Element serialize_post(const httplib::Request& req, const std::string& server, const Post& post) {
using namespace std::string_literals;
if (post.reblog) {
return serialize_post(req, server, *post.reblog);
}
std::string time_title = post.edited_at < 0
? full_time(post.created_at)
: "Created: "s + full_time(post.created_at) + "\nEdited: " + full_time(post.edited_at);
const char* time_badge = post.edited_at < 0 ? "" : " (edited)";
Element contents("div", {preprocess_html(req, server, post.emojis, post.content)});
Element post_attachments("div", {{"class", "post-attachments"}}, {});
post_attachments.nodes.reserve(post.media_attachments.size());
for (const Media& media : post.media_attachments) {
post_attachments.nodes.push_back(serialize_media(media));
}
contents.nodes.push_back(std::move(post_attachments));
if (post.sensitive) {
std::string spoiler_text = !post.spoiler_text.empty() ? post.spoiler_text : "See more";
contents = Element("details", {
Element("summary", {preprocess_html(req, post.emojis, std::move(spoiler_text))}),
std::move(contents),
});
}
Element div("div", {{"class", "post"}}, {
Element("div", {{"class", "post-header"}}, {
Element("a", {{"href", get_origin(req) + '/' + server + "/@" + post.account.acct(false)}}, {
Element("img", {{"class", "post-avatar"}, {"alt", "User profile picture"}, {"src", post.account.avatar_static}}, {}),
Element("span", {
Element("b", {preprocess_html(req, post.account.emojis, post.account.display_name)}),
Element("br"), "@", post.account.acct(),
}),
}),
Element("a", {{"href", get_origin(req) + '/' + server + "/@" + post.account.acct(false) + '/' + post.id}, {"title", time_title}}, {
Element("time", {{"datetime", to_rfc3339(post.created_at)}}, {relative_time(post.created_at, current_time()), time_badge}),
}),
}),
contents,
});
return div;
}
blankie::html::HTMLString preprocess_html(const httplib::Request& req, const std::string& domain_name, const std::vector<Emoji>& emojis, const blankie::html::HTMLString& str) {
LXB::HTML::Document document(str.str);
preprocess_html(req, domain_name, emojis, document.body_element());
return blankie::html::HTMLString(document.serialize());
}
blankie::html::HTMLString preprocess_html(const httplib::Request& req, const std::vector<Emoji>& emojis, const std::string& str) {
return preprocess_html(req, "", emojis, blankie::html::HTMLString(blankie::html::escape(str)));
}
static inline void preprocess_html(const httplib::Request& req, const std::string& domain_name, const std::vector<Emoji>& emojis, lxb_dom_element_t* element) {
const char* tag_name = reinterpret_cast<const char*>(lxb_dom_element_tag_name(element, nullptr));
if (strncmp(tag_name, "A", 2) == 0) {
// Proprocess links
preprocess_link(req, domain_name, element);
}
// Walk through the element's children
lxb_dom_node_t* child = lxb_dom_node_first_child(lxb_dom_interface_node(element));
while (child) {
if (child->type == LXB_DOM_NODE_TYPE_ELEMENT) {
preprocess_html(req, domain_name, emojis, lxb_dom_interface_element(child));
} else if (child->type == LXB_DOM_NODE_TYPE_TEXT) {
child = emojify(child, emojis);
}
child = lxb_dom_node_next(child);
}
}
static std::regex mention_class_re("\\bmention\\b");
static inline void preprocess_link(const httplib::Request& req, const std::string& domain_name, lxb_dom_element_t* element) {
using namespace std::string_literals;
size_t href_c_len;
const lxb_char_t* href_c = lxb_dom_element_get_attribute(element, reinterpret_cast<const lxb_char_t*>("href"), 4, &href_c_len);
if (!href_c) {
return;
}
std::string href(reinterpret_cast<const char*>(href_c), href_c_len);
size_t cls_c_len;
const lxb_char_t* cls_c = lxb_dom_element_class(element, &cls_c_len);
std::string cls = cls_c ? std::string(reinterpret_cast<const char*>(cls_c), cls_c_len) : "";
std::string instance_url_base = "https://"s + domain_name;
// .mention is used in note and posts
// Instance base is used for link fields
if (std::regex_search(cls, mention_class_re) || href.starts_with(instance_url_base + '/') || href == instance_url_base) {
// Proxy this instance's URLs to Coyote
href = proxy_mastodon_url(req, std::move(href));
lxb_dom_element_set_attribute(element, reinterpret_cast<const lxb_char_t*>("href"), 4, reinterpret_cast<const lxb_char_t*>(href.data()), href.size());
}
if (should_fix_link(element, cls)) {
// Set the content of each <a> to its href
lxb_status_t status = lxb_dom_node_text_content_set(lxb_dom_interface_node(element), reinterpret_cast<const lxb_char_t*>(href.data()), href.size());
if (status != LXB_STATUS_OK) {
throw LXB::Exception(status);
}
}
}
static std::regex unhandled_link_re("\\bunhandled-link\\b");
static inline bool should_fix_link(lxb_dom_element_t* element, const std::string& cls) {
// https://vt.social/@LucydiaLuminous/111448085044245037
if (std::regex_search(cls, unhandled_link_re)) {
return true;
}
auto expected_element = [](lxb_dom_node_t* node, const char* expected_cls) {
if (node->type != LXB_DOM_NODE_TYPE_ELEMENT) {
return false;
}
lxb_dom_element_t* span = lxb_dom_interface_element(node);
const char* tag_name = reinterpret_cast<const char*>(lxb_dom_element_tag_name(span, nullptr));
if (strncmp(tag_name, "SPAN", 5) != 0) {
return false;
}
const lxb_char_t* cls = lxb_dom_element_get_attribute(span, reinterpret_cast<const lxb_char_t*>("class"), 5, nullptr);
return cls && strcmp(reinterpret_cast<const char*>(cls), expected_cls) == 0;
};
lxb_dom_node_t* child = lxb_dom_node_first_child(lxb_dom_interface_node(element));
if (!expected_element(child, "invisible")) {
return false;
}
child = lxb_dom_node_next(child);
if (!expected_element(child, "ellipsis") && !expected_element(child, "")) {
return false;
}
child = lxb_dom_node_next(child);
if (!expected_element(child, "invisible")) {
return false;
}
child = lxb_dom_node_next(child);
return child == nullptr;
}
static inline lxb_dom_node_t* emojify(lxb_dom_node_t* child, const std::vector<Emoji>& emojis) {
size_t text_content_len;
const char* text_content = reinterpret_cast<const char*>(lxb_dom_node_text_content(child, &text_content_len));
std::vector<lxb_dom_node_t*> nodes = emojify(child->owner_document, std::string(text_content, text_content_len), emojis);
lxb_dom_node_insert_after(child, nodes[0]);
lxb_dom_node_destroy(child);
child = nodes[0];
for (size_t i = 1; i < nodes.size(); i++) {
lxb_dom_node_insert_after(child, nodes[i]);
child = nodes[i];
}
return child;
}
static std::regex shortcode_re(":([a-zA-Z0-9_]+):");
static inline std::vector<lxb_dom_node_t*> emojify(lxb_dom_document_t* document, std::string str, const std::vector<Emoji>& emojis) {
std::string buf;
std::smatch sm;
std::vector<lxb_dom_node*> res;
while (std::regex_search(str, sm, shortcode_re)) {
buf += sm.prefix();
std::string group_0 = sm.str(0);
auto emoji = std::find_if(emojis.begin(), emojis.end(), [&](const Emoji& i) { return i.shortcode == sm.str(1); });
if (emoji != emojis.end()) {
res.push_back(lxb_dom_interface_node(lxb_dom_document_create_text_node(document, reinterpret_cast<const lxb_char_t*>(buf.data()), buf.size())));
buf.clear();
lxb_dom_element_t* img = lxb_dom_element_create(document, reinterpret_cast<const lxb_char_t*>("IMG"), 3, nullptr, 0, nullptr, 0, nullptr, 0, false);
lxb_dom_element_set_attribute(img, reinterpret_cast<const lxb_char_t*>("class"), 5, reinterpret_cast<const lxb_char_t*>("custom_emoji"), 12);
lxb_dom_element_set_attribute(img, reinterpret_cast<const lxb_char_t*>("alt"), 3, reinterpret_cast<const lxb_char_t*>(group_0.data()), group_0.size());
lxb_dom_element_set_attribute(img, reinterpret_cast<const lxb_char_t*>("title"), 5, reinterpret_cast<const lxb_char_t*>(group_0.data()), group_0.size());
lxb_dom_element_set_attribute(img, reinterpret_cast<const lxb_char_t*>("src"), 3, reinterpret_cast<const lxb_char_t*>(emoji->url.data()), emoji->url.size());
res.push_back(lxb_dom_interface_node(img));
} else {
buf += group_0;
}
str = sm.suffix();
}
if (!str.empty()) {
buf += std::move(str);
}
if (!buf.empty()) {
res.push_back(lxb_dom_interface_node(lxb_dom_document_create_text_node(document, reinterpret_cast<const lxb_char_t*>(buf.data()), buf.size())));
}
return res;
}
static inline Element serialize_media(const Media& media) {
Element element = [&]() {
if (media.type == "image") {
return Element("a", {{"href", media.url}}, {
Element("img", {{"src", media.preview_url.value_or(media.url)}}, {}),
});
} else if (media.type == "video") {
Element video("video", {{"controls", ""}, {"src", media.url}}, {});
if (media.preview_url) {
video.attributes.push_back({"poster", *media.preview_url});
}
return video;
} else if (media.type == "audio") {
return Element("audio", {{"controls", ""}, {"src", media.url}}, {});
} else if (media.type == "unknown" && media.remote_url) {
if (media.remote_url) {
// https://botsin.space/@lina@vt.social/111053598696451525
return Element("a", {{"href", *media.remote_url}}, {"Media is not available from this instance, view externally"});
} else {
return Element("p", {"Media is not available from this instance"});
}
} else {
return Element("p", {"Unsupported media type: ", media.type});
}
}();
if (media.description) {
element.attributes.push_back({"alt", *media.description});
element.attributes.push_back({"title", *media.description});
}
return element;
}