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tilemaker/server/Simple-Web-Server/utility.hpp
2024-01-01 23:07:13 +00:00

480 lines
16 KiB
C++

#ifndef SIMPLE_WEB_UTILITY_HPP
#define SIMPLE_WEB_UTILITY_HPP
#include "status_code.hpp"
#include <atomic>
#include <chrono>
#include <cstdlib>
#include <ctime>
#include <iostream>
#include <memory>
#include <mutex>
#include <string>
#include <unordered_map>
#ifndef DEPRECATED
#if defined(__GNUC__) || defined(__clang__)
#define DEPRECATED __attribute__((deprecated))
#elif defined(_MSC_VER)
#define DEPRECATED __declspec(deprecated)
#else
#define DEPRECATED
#endif
#endif
#if __cplusplus > 201402L || _MSVC_LANG > 201402L
#include <string_view>
namespace SimpleWeb {
using string_view = std::string_view;
}
#elif !defined(ASIO_STANDALONE)
#include <boost/utility/string_ref.hpp>
namespace SimpleWeb {
using string_view = boost::string_ref;
}
#else
namespace SimpleWeb {
using string_view = const std::string &;
}
#endif
namespace SimpleWeb {
inline bool case_insensitive_equal(const std::string &str1, const std::string &str2) noexcept {
return str1.size() == str2.size() &&
std::equal(str1.begin(), str1.end(), str2.begin(), [](char a, char b) {
return tolower(a) == tolower(b);
});
}
class CaseInsensitiveEqual {
public:
bool operator()(const std::string &str1, const std::string &str2) const noexcept {
return case_insensitive_equal(str1, str2);
}
};
// Based on https://stackoverflow.com/questions/2590677/how-do-i-combine-hash-values-in-c0x/2595226#2595226
class CaseInsensitiveHash {
public:
std::size_t operator()(const std::string &str) const noexcept {
std::size_t h = 0;
std::hash<int> hash;
for(auto c : str)
h ^= hash(tolower(c)) + 0x9e3779b9 + (h << 6) + (h >> 2);
return h;
}
};
using CaseInsensitiveMultimap = std::unordered_multimap<std::string, std::string, CaseInsensitiveHash, CaseInsensitiveEqual>;
/// Percent encoding and decoding
class Percent {
public:
/// Returns percent-encoded string
static std::string encode(const std::string &value) noexcept {
static auto hex_chars = "0123456789ABCDEF";
std::string result;
result.reserve(value.size()); // Minimum size of result
for(auto &chr : value) {
if(!((chr >= '0' && chr <= '9') || (chr >= 'A' && chr <= 'Z') || (chr >= 'a' && chr <= 'z') || chr == '-' || chr == '.' || chr == '_' || chr == '~'))
result += std::string("%") + hex_chars[static_cast<unsigned char>(chr) >> 4] + hex_chars[static_cast<unsigned char>(chr) & 15];
else
result += chr;
}
return result;
}
/// Returns percent-decoded string
static std::string decode(const std::string &value) noexcept {
std::string result;
result.reserve(value.size() / 3 + (value.size() % 3)); // Minimum size of result
for(std::size_t i = 0; i < value.size(); ++i) {
auto &chr = value[i];
if(chr == '%' && i + 2 < value.size()) {
auto hex = value.substr(i + 1, 2);
auto decoded_chr = static_cast<char>(std::strtol(hex.c_str(), nullptr, 16));
result += decoded_chr;
i += 2;
}
else if(chr == '+')
result += ' ';
else
result += chr;
}
return result;
}
};
/// Query string creation and parsing
class QueryString {
public:
/// Returns query string created from given field names and values
static std::string create(const CaseInsensitiveMultimap &fields) noexcept {
std::string result;
bool first = true;
for(auto &field : fields) {
result += (!first ? "&" : "") + field.first + '=' + Percent::encode(field.second);
first = false;
}
return result;
}
/// Returns query keys with percent-decoded values.
static CaseInsensitiveMultimap parse(const std::string &query_string) noexcept {
CaseInsensitiveMultimap result;
if(query_string.empty())
return result;
std::size_t name_pos = 0;
auto name_end_pos = std::string::npos;
auto value_pos = std::string::npos;
for(std::size_t c = 0; c < query_string.size(); ++c) {
if(query_string[c] == '&') {
auto name = query_string.substr(name_pos, (name_end_pos == std::string::npos ? c : name_end_pos) - name_pos);
if(!name.empty()) {
auto value = value_pos == std::string::npos ? std::string() : query_string.substr(value_pos, c - value_pos);
result.emplace(std::move(name), Percent::decode(value));
}
name_pos = c + 1;
name_end_pos = std::string::npos;
value_pos = std::string::npos;
}
else if(query_string[c] == '=' && name_end_pos == std::string::npos) {
name_end_pos = c;
value_pos = c + 1;
}
}
if(name_pos < query_string.size()) {
auto name = query_string.substr(name_pos, (name_end_pos == std::string::npos ? std::string::npos : name_end_pos - name_pos));
if(!name.empty()) {
auto value = value_pos >= query_string.size() ? std::string() : query_string.substr(value_pos);
result.emplace(std::move(name), Percent::decode(value));
}
}
return result;
}
};
class HttpHeader {
public:
/// Parse header fields from stream
static CaseInsensitiveMultimap parse(std::istream &stream) noexcept {
CaseInsensitiveMultimap result;
std::string line;
std::size_t param_end;
while(getline(stream, line) && (param_end = line.find(':')) != std::string::npos) {
std::size_t value_start = param_end + 1;
while(value_start + 1 < line.size() && line[value_start] == ' ')
++value_start;
if(value_start < line.size())
result.emplace(line.substr(0, param_end), line.substr(value_start, line.size() - value_start - (line.back() == '\r' ? 1 : 0)));
}
return result;
}
class FieldValue {
public:
class SemicolonSeparatedAttributes {
public:
/// Parse Set-Cookie or Content-Disposition from given header field value.
/// Attribute values are percent-decoded.
static CaseInsensitiveMultimap parse(const std::string &value) {
CaseInsensitiveMultimap result;
std::size_t name_start_pos = std::string::npos;
std::size_t name_end_pos = std::string::npos;
std::size_t value_start_pos = std::string::npos;
for(std::size_t c = 0; c < value.size(); ++c) {
if(name_start_pos == std::string::npos) {
if(value[c] != ' ' && value[c] != ';')
name_start_pos = c;
}
else {
if(name_end_pos == std::string::npos) {
if(value[c] == ';') {
result.emplace(value.substr(name_start_pos, c - name_start_pos), std::string());
name_start_pos = std::string::npos;
}
else if(value[c] == '=')
name_end_pos = c;
}
else {
if(value_start_pos == std::string::npos) {
if(value[c] == '"' && c + 1 < value.size())
value_start_pos = c + 1;
else
value_start_pos = c;
}
else if(value[c] == '"' || value[c] == ';') {
result.emplace(value.substr(name_start_pos, name_end_pos - name_start_pos), Percent::decode(value.substr(value_start_pos, c - value_start_pos)));
name_start_pos = std::string::npos;
name_end_pos = std::string::npos;
value_start_pos = std::string::npos;
}
}
}
}
if(name_start_pos != std::string::npos) {
if(name_end_pos == std::string::npos)
result.emplace(value.substr(name_start_pos), std::string());
else if(value_start_pos != std::string::npos) {
if(value.back() == '"')
result.emplace(value.substr(name_start_pos, name_end_pos - name_start_pos), Percent::decode(value.substr(value_start_pos, value.size() - 1)));
else
result.emplace(value.substr(name_start_pos, name_end_pos - name_start_pos), Percent::decode(value.substr(value_start_pos)));
}
}
return result;
}
};
};
};
class RequestMessage {
public:
/** Parse request line and header fields from a request stream.
*
* @param[in] stream Stream to parse.
* @param[out] method HTTP method.
* @param[out] path Path from request URI.
* @param[out] query_string Query string from request URI.
* @param[out] version HTTP version.
* @param[out] header Header fields.
*
* @return True if stream is parsed successfully, false if not.
*/
static bool parse(std::istream &stream, std::string &method, std::string &path, std::string &query_string, std::string &version, CaseInsensitiveMultimap &header) noexcept {
std::string line;
std::size_t method_end;
if(getline(stream, line) && (method_end = line.find(' ')) != std::string::npos) {
method = line.substr(0, method_end);
std::size_t query_start = std::string::npos;
std::size_t path_and_query_string_end = std::string::npos;
for(std::size_t i = method_end + 1; i < line.size(); ++i) {
if(line[i] == '?' && (i + 1) < line.size() && query_start == std::string::npos)
query_start = i + 1;
else if(line[i] == ' ') {
path_and_query_string_end = i;
break;
}
}
if(path_and_query_string_end != std::string::npos) {
if(query_start != std::string::npos) {
path = line.substr(method_end + 1, query_start - method_end - 2);
query_string = line.substr(query_start, path_and_query_string_end - query_start);
}
else
path = line.substr(method_end + 1, path_and_query_string_end - method_end - 1);
std::size_t protocol_end;
if((protocol_end = line.find('/', path_and_query_string_end + 1)) != std::string::npos) {
if(line.compare(path_and_query_string_end + 1, protocol_end - path_and_query_string_end - 1, "HTTP") != 0)
return false;
version = line.substr(protocol_end + 1, line.size() - protocol_end - 2);
}
else
return false;
header = HttpHeader::parse(stream);
}
else
return false;
}
else
return false;
return true;
}
};
class ResponseMessage {
public:
/** Parse status line and header fields from a response stream.
*
* @param[in] stream Stream to parse.
* @param[out] version HTTP version.
* @param[out] status_code HTTP status code.
* @param[out] header Header fields.
*
* @return True if stream is parsed successfully, false if not.
*/
static bool parse(std::istream &stream, std::string &version, std::string &status_code, CaseInsensitiveMultimap &header) noexcept {
std::string line;
std::size_t version_end;
if(getline(stream, line) && (version_end = line.find(' ')) != std::string::npos) {
if(5 < line.size())
version = line.substr(5, version_end - 5);
else
return false;
if((version_end + 1) < line.size())
status_code = line.substr(version_end + 1, line.size() - (version_end + 1) - (line.back() == '\r' ? 1 : 0));
else
return false;
header = HttpHeader::parse(stream);
}
else
return false;
return true;
}
};
/// Date class working with formats specified in RFC 7231 Date/Time Formats
class Date {
public:
/// Returns the given std::chrono::system_clock::time_point as a string with the following format: Wed, 31 Jul 2019 11:34:23 GMT.
static std::string to_string(const std::chrono::system_clock::time_point time_point) noexcept {
static std::string result_cache;
static std::chrono::system_clock::time_point last_time_point;
static std::mutex mutex;
std::lock_guard<std::mutex> lock(mutex);
if(std::chrono::duration_cast<std::chrono::seconds>(time_point - last_time_point).count() == 0 && !result_cache.empty())
return result_cache;
last_time_point = time_point;
std::string result;
result.reserve(29);
auto time = std::chrono::system_clock::to_time_t(time_point);
tm tm;
#if defined(_MSC_VER) || defined(__MINGW32__)
if(gmtime_s(&tm, &time) != 0)
return {};
auto gmtime = &tm;
#else
auto gmtime = gmtime_r(&time, &tm);
if(!gmtime)
return {};
#endif
switch(gmtime->tm_wday) {
case 0: result += "Sun, "; break;
case 1: result += "Mon, "; break;
case 2: result += "Tue, "; break;
case 3: result += "Wed, "; break;
case 4: result += "Thu, "; break;
case 5: result += "Fri, "; break;
case 6: result += "Sat, "; break;
}
result += gmtime->tm_mday < 10 ? '0' : static_cast<char>(gmtime->tm_mday / 10 + 48);
result += static_cast<char>(gmtime->tm_mday % 10 + 48);
switch(gmtime->tm_mon) {
case 0: result += " Jan "; break;
case 1: result += " Feb "; break;
case 2: result += " Mar "; break;
case 3: result += " Apr "; break;
case 4: result += " May "; break;
case 5: result += " Jun "; break;
case 6: result += " Jul "; break;
case 7: result += " Aug "; break;
case 8: result += " Sep "; break;
case 9: result += " Oct "; break;
case 10: result += " Nov "; break;
case 11: result += " Dec "; break;
}
auto year = gmtime->tm_year + 1900;
result += static_cast<char>(year / 1000 + 48);
result += static_cast<char>((year / 100) % 10 + 48);
result += static_cast<char>((year / 10) % 10 + 48);
result += static_cast<char>(year % 10 + 48);
result += ' ';
result += gmtime->tm_hour < 10 ? '0' : static_cast<char>(gmtime->tm_hour / 10 + 48);
result += static_cast<char>(gmtime->tm_hour % 10 + 48);
result += ':';
result += gmtime->tm_min < 10 ? '0' : static_cast<char>(gmtime->tm_min / 10 + 48);
result += static_cast<char>(gmtime->tm_min % 10 + 48);
result += ':';
result += gmtime->tm_sec < 10 ? '0' : static_cast<char>(gmtime->tm_sec / 10 + 48);
result += static_cast<char>(gmtime->tm_sec % 10 + 48);
result += " GMT";
result_cache = result;
return result;
}
};
} // namespace SimpleWeb
#ifdef __SSE2__
#include <emmintrin.h>
namespace SimpleWeb {
inline void spin_loop_pause() noexcept { _mm_pause(); }
} // namespace SimpleWeb
// TODO: need verification that the following checks are correct:
#elif defined(_MSC_VER) && _MSC_VER >= 1800 && (defined(_M_X64) || defined(_M_IX86))
#include <intrin.h>
namespace SimpleWeb {
inline void spin_loop_pause() noexcept { _mm_pause(); }
} // namespace SimpleWeb
#else
namespace SimpleWeb {
inline void spin_loop_pause() noexcept {}
} // namespace SimpleWeb
#endif
namespace SimpleWeb {
/// Makes it possible to for instance cancel Asio handlers without stopping asio::io_service.
class ScopeRunner {
/// Scope count that is set to -1 if scopes are to be canceled.
std::atomic<long> count;
public:
class SharedLock {
friend class ScopeRunner;
std::atomic<long> &count;
SharedLock(std::atomic<long> &count) noexcept : count(count) {}
SharedLock &operator=(const SharedLock &) = delete;
SharedLock(const SharedLock &) = delete;
public:
~SharedLock() noexcept {
count.fetch_sub(1);
}
};
ScopeRunner() noexcept : count(0) {}
/// Returns nullptr if scope should be exited, or a shared lock otherwise.
/// The shared lock ensures that a potential destructor call is delayed until all locks are released.
std::unique_ptr<SharedLock> continue_lock() noexcept {
long expected = count;
while(expected >= 0 && !count.compare_exchange_weak(expected, expected + 1))
spin_loop_pause();
if(expected < 0)
return nullptr;
else
return std::unique_ptr<SharedLock>(new SharedLock(count));
}
/// Blocks until all shared locks are released, then prevents future shared locks.
void stop() noexcept {
long expected = 0;
while(!count.compare_exchange_weak(expected, -1)) {
if(expected < 0)
return;
expected = 0;
spin_loop_pause();
}
}
};
} // namespace SimpleWeb
#endif // SIMPLE_WEB_UTILITY_HPP