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transmission/libtransmission/web-utils.cc
2023-07-08 10:24:03 -05:00

463 lines
11 KiB
C++

// This file Copyright © 2021-2023 Mnemosyne LLC.
// It may be used under GPLv2 (SPDX: GPL-2.0-only), GPLv3 (SPDX: GPL-3.0-only),
// or any future license endorsed by Mnemosyne LLC.
// License text can be found in the licenses/ folder.
#include <algorithm>
#include <array>
#include <cctype>
#include <cstdlib> // for strtoul()
#include <limits>
#include <optional>
#include <string>
#include <string_view>
#include <utility>
#include <fmt/core.h>
#define PSL_STATIC
#include <libpsl.h>
#include "libtransmission/log.h"
#include "libtransmission/net.h"
#include "libtransmission/tr-assert.h"
#include "libtransmission/tr-macros.h"
#include "libtransmission/tr-strbuf.h"
#include "libtransmission/utils.h"
#include "libtransmission/web-utils.h"
using namespace std::literals;
// ---
bool tr_addressIsIP(char const* address)
{
return address != nullptr && tr_address::from_string(address).has_value();
}
char const* tr_webGetResponseStr(long code)
{
switch (code)
{
case 0:
return "No Response";
case 101:
return "Switching Protocols";
case 200:
return "OK";
case 201:
return "Created";
case 202:
return "Accepted";
case 203:
return "Non-Authoritative Information";
case 204:
return "No Content";
case 205:
return "Reset Content";
case 206:
return "Partial Content";
case 300:
return "Multiple Choices";
case 301:
return "Moved Permanently";
case 302:
return "Found";
case 303:
return "See Other";
case 304:
return "Not Modified";
case 305:
return "Use Proxy";
case 306:
return " (Unused)";
case 307:
return "Temporary Redirect";
case 400:
return "Bad Request";
case 401:
return "Unauthorized";
case 402:
return "Payment Required";
case 403:
return "Forbidden";
case 404:
return "Not Found";
case 405:
return "Method Not Allowed";
case 406:
return "Not Acceptable";
case 407:
return "Proxy Authentication Required";
case 408:
return "Request Timeout";
case 409:
return "Conflict";
case 410:
return "Gone";
case 411:
return "Length Required";
case 412:
return "Precondition Failed";
case 413:
return "Request Entity Too Large";
case 414:
return "Request-URI Too Long";
case 415:
return "Unsupported Media Type";
case 416:
return "Requested Range Not Satisfiable";
case 417:
return "Expectation Failed";
case 421:
return "Misdirected Request";
case 500:
return "Internal Server Error";
case 501:
return "Not Implemented";
case 502:
return "Bad Gateway";
case 503:
return "Service Unavailable";
case 504:
return "Gateway Timeout";
case 505:
return "HTTP Version Not Supported";
default:
return "Unknown Error";
}
}
// --- URLs
namespace
{
auto parsePort(std::string_view port_sv)
{
auto const port = tr_num_parse<int>(port_sv);
using PortLimits = std::numeric_limits<uint16_t>;
return port && PortLimits::min() <= *port && *port <= PortLimits::max() ? *port : -1;
}
constexpr std::string_view getPortForScheme(std::string_view scheme)
{
auto constexpr KnownSchemes = std::array<std::pair<std::string_view, std::string_view>, 5>{ {
{ "ftp"sv, "21"sv },
{ "http"sv, "80"sv },
{ "https"sv, "443"sv },
{ "sftp"sv, "22"sv },
{ "udp"sv, "80"sv },
} };
for (auto const& [known_scheme, port] : KnownSchemes)
{
if (scheme == known_scheme)
{
return port;
}
}
return "-1"sv;
}
TR_CONSTEXPR20 bool urlCharsAreValid(std::string_view url)
{
// rfc2396
auto constexpr ValidChars = std::string_view{
"abcdefghijklmnopqrstuvwxyz" // lowalpha
"ABCDEFGHIJKLMNOPQRSTUVWXYZ" // upalpha
"0123456789" // digit
"-_.!~*'()" // mark
";/?:@&=+$," // reserved
"<>#%<\"" // delims
"{}|\\^[]`" // unwise
};
return !std::empty(url) &&
std::all_of(std::begin(url), std::end(url), [&ValidChars](auto ch) { return tr_strv_contains(ValidChars, ch); });
}
bool tr_isValidTrackerScheme(std::string_view scheme)
{
auto constexpr Schemes = std::array<std::string_view, 3>{ "http"sv, "https"sv, "udp"sv };
return std::find(std::begin(Schemes), std::end(Schemes), scheme) != std::end(Schemes);
}
bool isAsciiNonUpperCase(std::string_view host)
{
return std::all_of(
std::begin(host),
std::end(host),
[](unsigned char ch) { return (ch < 128) && (std::isupper(ch) == 0); });
}
// www.example.com -> example
// www.example.co.uk -> example
// 127.0.0.1 -> 127.0.0.1
std::string_view getSiteName(std::string_view host)
{
// is it empty?
if (std::empty(host))
{
return host;
}
// is it an IP?
if (auto const addr = tr_address::from_string(host); addr)
{
return host;
}
TR_ASSERT(psl_builtin() != nullptr);
if (psl_builtin() == nullptr)
{
tr_logAddWarn("psl_builtin is null");
return host;
}
// psl needs a zero-terminated hostname
auto const szhost = tr_urlbuf{ host };
// is it a registered name?
if (isAsciiNonUpperCase(host))
{
// www.example.co.uk -> example.co.uk
if (char const* const top = psl_registrable_domain(psl_builtin(), std::data(szhost)); top != nullptr)
{
host.remove_prefix(top - std::data(szhost));
}
}
else if (char* lower = nullptr; psl_str_to_utf8lower(std::data(szhost), nullptr, nullptr, &lower) == PSL_SUCCESS)
{
// www.example.co.uk -> example.co.uk
if (char const* const top = psl_registrable_domain(psl_builtin(), lower); top != nullptr)
{
host.remove_prefix(top - lower);
}
psl_free_string(lower);
}
// example.co.uk -> example
if (auto const dot_pos = host.find('.'); dot_pos != std::string_view::npos)
{
host = host.substr(0, dot_pos);
}
return host;
}
} // namespace
std::optional<tr_url_parsed_t> tr_urlParse(std::string_view url)
{
url = tr_strv_strip(url);
auto parsed = tr_url_parsed_t{};
parsed.full = url;
// So many magnet links are malformed, e.g. not escaping text
// in the display name, that we're better off handling magnets
// as a special case before even scanning for invalid chars.
if (auto constexpr MagnetStart = "magnet:?"sv; tr_strv_starts_with(url, MagnetStart))
{
parsed.scheme = "magnet"sv;
parsed.query = url.substr(std::size(MagnetStart));
return parsed;
}
if (!urlCharsAreValid(url))
{
return std::nullopt;
}
// scheme
parsed.scheme = tr_strv_sep(&url, ':');
if (std::empty(parsed.scheme))
{
return std::nullopt;
}
// authority
// The authority component is preceded by a double slash ("//") and is
// terminated by the next slash ("/"), question mark ("?"), or number
// sign ("#") character, or by the end of the URI.
if (auto key = "//"sv; tr_strv_starts_with(url, key))
{
url.remove_prefix(std::size(key));
auto pos = url.find_first_of("/?#");
parsed.authority = url.substr(0, pos);
url = pos == std::string_view::npos ? ""sv : url.substr(pos);
// A host identified by an Internet Protocol literal address, version 6
// [RFC3513] or later, is distinguished by enclosing the IP literal
// within square brackets ("[" and "]"). This is the only place where
// square bracket characters are allowed in the URI syntax.
auto remain = parsed.authority;
if (tr_strv_starts_with(remain, '['))
{
remain.remove_prefix(1); // '['
parsed.host = tr_strv_sep(&remain, ']');
if (tr_strv_starts_with(remain, ':'))
{
remain.remove_prefix(1);
}
}
// Not legal by RFC3986 standards, but sometimes users omit
// square brackets for an IPv6 address with an implicit port
else if (std::count(std::begin(remain), std::end(remain), ':') > 1U)
{
parsed.host = remain;
remain = ""sv;
}
else
{
parsed.host = tr_strv_sep(&remain, ':');
}
parsed.sitename = getSiteName(parsed.host);
parsed.port = parsePort(!std::empty(remain) ? remain : getPortForScheme(parsed.scheme));
}
// The path is terminated by the first question mark ("?") or
// number sign ("#") character, or by the end of the URI.
auto pos = url.find_first_of("?#");
parsed.path = url.substr(0, pos);
url = pos == std::string_view::npos ? ""sv : url.substr(pos);
// query
if (tr_strv_starts_with(url, '?'))
{
url.remove_prefix(1);
pos = url.find('#');
parsed.query = url.substr(0, pos);
url = pos == std::string_view::npos ? ""sv : url.substr(pos);
}
// fragment
if (tr_strv_starts_with(url, '#'))
{
parsed.fragment = url.substr(1);
}
return parsed;
}
std::optional<tr_url_parsed_t> tr_urlParseTracker(std::string_view url)
{
auto const parsed = tr_urlParse(url);
return parsed && tr_isValidTrackerScheme(parsed->scheme) ? std::make_optional(*parsed) : std::nullopt;
}
bool tr_urlIsValidTracker(std::string_view url)
{
return !!tr_urlParseTracker(url);
}
bool tr_urlIsValid(std::string_view url)
{
auto constexpr Schemes = std::array<std::string_view, 5>{ "http"sv, "https"sv, "ftp"sv, "sftp"sv, "udp"sv };
auto const parsed = tr_urlParse(url);
return parsed && std::find(std::begin(Schemes), std::end(Schemes), parsed->scheme) != std::end(Schemes);
}
std::string tr_urlTrackerLogName(std::string_view url)
{
if (auto const parsed = tr_urlParse(url); parsed)
{
return fmt::format(FMT_STRING("{:s}://{:s}:{:d}"), parsed->scheme, parsed->host, parsed->port);
}
// we have an invalid URL, we log the full string
return std::string{ url };
}
tr_url_query_view::iterator& tr_url_query_view::iterator::operator++()
{
auto pair = tr_strv_sep(&remain, '&');
keyval.first = tr_strv_sep(&pair, '=');
keyval.second = pair;
return *this;
}
tr_url_query_view::iterator tr_url_query_view::begin() const
{
auto it = iterator{};
it.remain = query;
++it;
return it;
}
std::string tr_urlPercentDecode(std::string_view in)
{
auto out = std::string{};
out.reserve(std::size(in));
for (;;)
{
auto pos = in.find('%');
out += in.substr(0, pos);
if (pos == std::string_view::npos)
{
break;
}
in.remove_prefix(pos);
if (std::size(in) >= 3 && in[0] == '%' && (std::isxdigit(in[1]) != 0) && (std::isxdigit(in[2]) != 0))
{
auto hexstr = std::array<char, 3>{ in[1], in[2], '\0' };
auto const hex = strtoul(std::data(hexstr), nullptr, 16);
out += char(hex);
in.remove_prefix(3);
}
else
{
out += in.front();
in.remove_prefix(1);
}
}
return out;
}