Repository: ggml-org/llama.cpp
Pull request: server : Support listening on a unix socket

Add support for listening on a unix socket in the example server.

To keep the change small, and avoid extending the set of cli flags I went with a slightly hacky way of passing the socket name to the server. I.e. if `--host` ends with `.sock` then create and listen on a unix socket, else listen on TCP. LMK if this is acceptable, or if it would be better to avoid overloading `--host` and create an additional cli flag?

Changed files:
filename: common/arg.cpp
patch: @@ -1979,7 +1979,7 @@ common_params_context common_params_parser_init(common_params & params, llama_ex
     ).set_examples({LLAMA_EXAMPLE_EMBEDDING}));
     add_opt(common_arg(
         {"--host"}, "HOST",
-        string_format("ip address to listen (default: %s)", params.hostname.c_str()),
+        string_format("ip address to listen, or bind to an UNIX socket if the address ends with .sock (default: %s)", params.hostname.c_str()),
         [](common_params & params, const std::string & value) {
             params.hostname = value;
         }

filename: examples/server/httplib.h
patch: @@ -8,7 +8,7 @@
 #ifndef CPPHTTPLIB_HTTPLIB_H
 #define CPPHTTPLIB_HTTPLIB_H
 
-#define CPPHTTPLIB_VERSION "0.19.0"
+#define CPPHTTPLIB_VERSION "0.20.0"
 
 /*
  * Configuration
@@ -188,15 +188,16 @@ using ssize_t = long;
 #include <winsock2.h>
 #include <ws2tcpip.h>
 
+// afunix.h uses types declared in winsock2.h, so has to be included after it.
+#include <afunix.h>
+
 #ifndef WSA_FLAG_NO_HANDLE_INHERIT
 #define WSA_FLAG_NO_HANDLE_INHERIT 0x80
 #endif
 
+using nfds_t = unsigned long;
 using socket_t = SOCKET;
 using socklen_t = int;
-#ifdef CPPHTTPLIB_USE_POLL
-#define poll(fds, nfds, timeout) WSAPoll(fds, nfds, timeout)
-#endif
 
 #else // not _WIN32
 
@@ -216,16 +217,11 @@ using socklen_t = int;
 #ifdef __linux__
 #include <resolv.h>
 #endif
+#include <csignal>
 #include <netinet/tcp.h>
-#ifdef CPPHTTPLIB_USE_POLL
 #include <poll.h>
-#endif
-#include <csignal>
 #include <pthread.h>
 #include <sys/mman.h>
-#ifndef __VMS
-#include <sys/select.h>
-#endif
 #include <sys/socket.h>
 #include <sys/un.h>
 #include <unistd.h>
@@ -247,7 +243,6 @@ using socket_t = int;
 #include <errno.h>
 #include <exception>
 #include <fcntl.h>
-#include <fstream>
 #include <functional>
 #include <iomanip>
 #include <iostream>
@@ -320,6 +315,10 @@ using socket_t = int;
 #include <brotli/encode.h>
 #endif
 
+#ifdef CPPHTTPLIB_ZSTD_SUPPORT
+#include <zstd.h>
+#endif
+
 /*
  * Declaration
  */
@@ -435,6 +434,15 @@ struct scope_exit {
 
 } // namespace detail
 
+enum SSLVerifierResponse {
+  // no decision has been made, use the built-in certificate verifier
+  NoDecisionMade,
+  // connection certificate is verified and accepted
+  CertificateAccepted,
+  // connection certificate was processed but is rejected
+  CertificateRejected
+};
+
 enum StatusCode {
   // Information responses
   Continue_100 = 100,
@@ -670,7 +678,7 @@ struct Request {
   bool is_chunked_content_provider_ = false;
   size_t authorization_count_ = 0;
   std::chrono::time_point<std::chrono::steady_clock> start_time_ =
-      std::chrono::steady_clock::time_point::min();
+      (std::chrono::steady_clock::time_point::min)();
 };
 
 struct Response {
@@ -736,7 +744,8 @@ class Stream {
   virtual ~Stream() = default;
 
   virtual bool is_readable() const = 0;
-  virtual bool is_writable() const = 0;
+  virtual bool wait_readable() const = 0;
+  virtual bool wait_writable() const = 0;
 
   virtual ssize_t read(char *ptr, size_t size) = 0;
   virtual ssize_t write(const char *ptr, size_t size) = 0;
@@ -879,7 +888,7 @@ class MatcherBase {
  * Captures parameters in request path and stores them in Request::path_params
  *
  * Capture name is a substring of a pattern from : to /.
- * The rest of the pattern is matched agains the request path directly
+ * The rest of the pattern is matched against the request path directly
  * Parameters are captured starting from the next character after
  * the end of the last matched static pattern fragment until the next /.
  *
@@ -1109,7 +1118,7 @@ class Server {
   virtual bool process_and_close_socket(socket_t sock);
 
   std::atomic<bool> is_running_{false};
-  std::atomic<bool> is_decommisioned{false};
+  std::atomic<bool> is_decommissioned{false};
 
   struct MountPointEntry {
     std::string mount_point;
@@ -1483,7 +1492,8 @@ class ClientImpl {
 #ifdef CPPHTTPLIB_OPENSSL_SUPPORT
   void enable_server_certificate_verification(bool enabled);
   void enable_server_hostname_verification(bool enabled);
-  void set_server_certificate_verifier(std::function<bool(SSL *ssl)> verifier);
+  void set_server_certificate_verifier(
+      std::function<SSLVerifierResponse(SSL *ssl)> verifier);
 #endif
 
   void set_logger(Logger logger);
@@ -1600,7 +1610,7 @@ class ClientImpl {
 #ifdef CPPHTTPLIB_OPENSSL_SUPPORT
   bool server_certificate_verification_ = true;
   bool server_hostname_verification_ = true;
-  std::function<bool(SSL *ssl)> server_certificate_verifier_;
+  std::function<SSLVerifierResponse(SSL *ssl)> server_certificate_verifier_;
 #endif
 
   Logger logger_;
@@ -1913,7 +1923,8 @@ class Client {
 #ifdef CPPHTTPLIB_OPENSSL_SUPPORT
   void enable_server_certificate_verification(bool enabled);
   void enable_server_hostname_verification(bool enabled);
-  void set_server_certificate_verifier(std::function<bool(SSL *ssl)> verifier);
+  void set_server_certificate_verifier(
+      std::function<SSLVerifierResponse(SSL *ssl)> verifier);
 #endif
 
   void set_logger(Logger logger);
@@ -2046,6 +2057,10 @@ inline void duration_to_sec_and_usec(const T &duration, U callback) {
   callback(static_cast<time_t>(sec), static_cast<time_t>(usec));
 }
 
+template <size_t N> inline constexpr size_t str_len(const char (&)[N]) {
+  return N - 1;
+}
+
 inline bool is_numeric(const std::string &str) {
   return !str.empty() && std::all_of(str.begin(), str.end(), ::isdigit);
 }
@@ -2205,9 +2220,9 @@ inline const char *status_message(int status) {
 
 inline std::string get_bearer_token_auth(const Request &req) {
   if (req.has_header("Authorization")) {
-    static std::string BearerHeaderPrefix = "Bearer ";
+    constexpr auto bearer_header_prefix_len = detail::str_len("Bearer ");
     return req.get_header_value("Authorization")
-        .substr(BearerHeaderPrefix.length());
+        .substr(bearer_header_prefix_len);
   }
   return "";
 }
@@ -2382,8 +2397,6 @@ std::string encode_query_param(const std::string &value);
 
 std::string decode_url(const std::string &s, bool convert_plus_to_space);
 
-void read_file(const std::string &path, std::string &out);
-
 std::string trim_copy(const std::string &s);
 
 void divide(
@@ -2439,7 +2452,7 @@ ssize_t send_socket(socket_t sock, const void *ptr, size_t size, int flags);
 
 ssize_t read_socket(socket_t sock, void *ptr, size_t size, int flags);
 
-enum class EncodingType { None = 0, Gzip, Brotli };
+enum class EncodingType { None = 0, Gzip, Brotli, Zstd };
 
 EncodingType encoding_type(const Request &req, const Response &res);
 
@@ -2449,7 +2462,8 @@ class BufferStream final : public Stream {
   ~BufferStream() override = default;
 
   bool is_readable() const override;
-  bool is_writable() const override;
+  bool wait_readable() const override;
+  bool wait_writable() const override;
   ssize_t read(char *ptr, size_t size) override;
   ssize_t write(const char *ptr, size_t size) override;
   void get_remote_ip_and_port(std::string &ip, int &port) const override;
@@ -2551,6 +2565,34 @@ class brotli_decompressor final : public decompressor {
 };
 #endif
 
+#ifdef CPPHTTPLIB_ZSTD_SUPPORT
+class zstd_compressor : public compressor {
+public:
+  zstd_compressor();
+  ~zstd_compressor();
+
+  bool compress(const char *data, size_t data_length, bool last,
+                Callback callback) override;
+
+private:
+  ZSTD_CCtx *ctx_ = nullptr;
+};
+
+class zstd_decompressor : public decompressor {
+public:
+  zstd_decompressor();
+  ~zstd_decompressor();
+
+  bool is_valid() const override;
+
+  bool decompress(const char *data, size_t data_length,
+                  Callback callback) override;
+
+private:
+  ZSTD_DCtx *ctx_ = nullptr;
+};
+#endif
+
 // NOTE: until the read size reaches `fixed_buffer_size`, use `fixed_buffer`
 // to store data. The call can set memory on stack for performance.
 class stream_line_reader {
@@ -2569,7 +2611,7 @@ class stream_line_reader {
   char *fixed_buffer_;
   const size_t fixed_buffer_size_;
   size_t fixed_buffer_used_size_ = 0;
-  std::string glowable_buffer_;
+  std::string growable_buffer_;
 };
 
 class mmap {
@@ -2910,18 +2952,9 @@ inline std::string decode_url(const std::string &s,
   return result;
 }
 
-inline void read_file(const std::string &path, std::string &out) {
-  std::ifstream fs(path, std::ios_base::binary);
-  fs.seekg(0, std::ios_base::end);
-  auto size = fs.tellg();
-  fs.seekg(0);
-  out.resize(static_cast<size_t>(size));
-  fs.read(&out[0], static_cast<std::streamsize>(size));
-}
-
 inline std::string file_extension(const std::string &path) {
   std::smatch m;
-  static auto re = std::regex("\\.([a-zA-Z0-9]+)$");
+  thread_local auto re = std::regex("\\.([a-zA-Z0-9]+)$");
   if (std::regex_search(path, m, re)) { return m[1].str(); }
   return std::string();
 }
@@ -3005,18 +3038,18 @@ inline stream_line_reader::stream_line_reader(Stream &strm, char *fixed_buffer,
       fixed_buffer_size_(fixed_buffer_size) {}
 
 inline const char *stream_line_reader::ptr() const {
-  if (glowable_buffer_.empty()) {
+  if (growable_buffer_.empty()) {
     return fixed_buffer_;
   } else {
-    return glowable_buffer_.data();
+    return growable_buffer_.data();
   }
 }
 
 inline size_t stream_line_reader::size() const {
-  if (glowable_buffer_.empty()) {
+  if (growable_buffer_.empty()) {
     return fixed_buffer_used_size_;
   } else {
-    return glowable_buffer_.size();
+    return growable_buffer_.size();
   }
 }
 
@@ -3027,7 +3060,7 @@ inline bool stream_line_reader::end_with_crlf() const {
 
 inline bool stream_line_reader::getline() {
   fixed_buffer_used_size_ = 0;
-  glowable_buffer_.clear();
+  growable_buffer_.clear();
 
 #ifndef CPPHTTPLIB_ALLOW_LF_AS_LINE_TERMINATOR
   char prev_byte = 0;
@@ -3065,11 +3098,11 @@ inline void stream_line_reader::append(char c) {
     fixed_buffer_[fixed_buffer_used_size_++] = c;
     fixed_buffer_[fixed_buffer_used_size_] = '\0';
   } else {
-    if (glowable_buffer_.empty()) {
+    if (growable_buffer_.empty()) {
       assert(fixed_buffer_[fixed_buffer_used_size_] == '\0');
-      glowable_buffer_.assign(fixed_buffer_, fixed_buffer_used_size_);
+      growable_buffer_.assign(fixed_buffer_, fixed_buffer_used_size_);
     }
-    glowable_buffer_ += c;
+    growable_buffer_ += c;
   }
 }
 
@@ -3246,35 +3279,23 @@ inline ssize_t send_socket(socket_t sock, const void *ptr, size_t size,
   });
 }
 
+inline int poll_wrapper(struct pollfd *fds, nfds_t nfds, int timeout) {
+#ifdef _WIN32
+  return ::WSAPoll(fds, nfds, timeout);
+#else
+  return ::poll(fds, nfds, timeout);
+#endif
+}
+
 template <bool Read>
 inline ssize_t select_impl(socket_t sock, time_t sec, time_t usec) {
-#ifdef CPPHTTPLIB_USE_POLL
   struct pollfd pfd;
   pfd.fd = sock;
   pfd.events = (Read ? POLLIN : POLLOUT);
 
   auto timeout = static_cast<int>(sec * 1000 + usec / 1000);
 
-  return handle_EINTR([&]() { return poll(&pfd, 1, timeout); });
-#else
-#ifndef _WIN32
-  if (sock >= FD_SETSIZE) { return -1; }
-#endif
-
-  fd_set fds, *rfds, *wfds;
-  FD_ZERO(&fds);
-  FD_SET(sock, &fds);
-  rfds = (Read ? &fds : nullptr);
-  wfds = (Read ? nullptr : &fds);
-
-  timeval tv;
-  tv.tv_sec = static_cast<long>(sec);
-  tv.tv_usec = static_cast<decltype(tv.tv_usec)>(usec);
-
-  return handle_EINTR([&]() {
-    return select(static_cast<int>(sock + 1), rfds, wfds, nullptr, &tv);
-  });
-#endif
+  return handle_EINTR([&]() { return poll_wrapper(&pfd, 1, timeout); });
 }
 
 inline ssize_t select_read(socket_t sock, time_t sec, time_t usec) {
@@ -3287,14 +3308,14 @@ inline ssize_t select_write(socket_t sock, time_t sec, time_t usec) {
 
 inline Error wait_until_socket_is_ready(socket_t sock, time_t sec,
                                         time_t usec) {
-#ifdef CPPHTTPLIB_USE_POLL
   struct pollfd pfd_read;
   pfd_read.fd = sock;
   pfd_read.events = POLLIN | POLLOUT;
 
   auto timeout = static_cast<int>(sec * 1000 + usec / 1000);
 
-  auto poll_res = handle_EINTR([&]() { return poll(&pfd_read, 1, timeout); });
+  auto poll_res =
+      handle_EINTR([&]() { return poll_wrapper(&pfd_read, 1, timeout); });
 
   if (poll_res == 0) { return Error::ConnectionTimeout; }
 
@@ -3308,38 +3329,6 @@ inline Error wait_until_socket_is_ready(socket_t sock, time_t sec,
   }
 
   return Error::Connection;
-#else
-#ifndef _WIN32
-  if (sock >= FD_SETSIZE) { return Error::Connection; }
-#endif
-
-  fd_set fdsr;
-  FD_ZERO(&fdsr);
-  FD_SET(sock, &fdsr);
-
-  auto fdsw = fdsr;
-  auto fdse = fdsr;
-
-  timeval tv;
-  tv.tv_sec = static_cast<long>(sec);
-  tv.tv_usec = static_cast<decltype(tv.tv_usec)>(usec);
-
-  auto ret = handle_EINTR([&]() {
-    return select(static_cast<int>(sock + 1), &fdsr, &fdsw, &fdse, &tv);
-  });
-
-  if (ret == 0) { return Error::ConnectionTimeout; }
-
-  if (ret > 0 && (FD_ISSET(sock, &fdsr) || FD_ISSET(sock, &fdsw))) {
-    auto error = 0;
-    socklen_t len = sizeof(error);
-    auto res = getsockopt(sock, SOL_SOCKET, SO_ERROR,
-                          reinterpret_cast<char *>(&error), &len);
-    auto successful = res >= 0 && !error;
-    return successful ? Error::Success : Error::Connection;
-  }
-  return Error::Connection;
-#endif
 }
 
 inline bool is_socket_alive(socket_t sock) {
@@ -3359,11 +3348,12 @@ class SocketStream final : public Stream {
                time_t write_timeout_sec, time_t write_timeout_usec,
                time_t max_timeout_msec = 0,
                std::chrono::time_point<std::chrono::steady_clock> start_time =
-                   std::chrono::steady_clock::time_point::min());
+                   (std::chrono::steady_clock::time_point::min)());
   ~SocketStream() override;
 
   bool is_readable() const override;
-  bool is_writable() const override;
+  bool wait_readable() const override;
+  bool wait_writable() const override;
   ssize_t read(char *ptr, size_t size) override;
   ssize_t write(const char *ptr, size_t size) override;
   void get_remote_ip_and_port(std::string &ip, int &port) const override;
@@ -3378,7 +3368,7 @@ class SocketStream final : public Stream {
   time_t write_timeout_sec_;
   time_t write_timeout_usec_;
   time_t max_timeout_msec_;
-  const std::chrono::time_point<std::chrono::steady_clock> start_time;
+  const std::chrono::time_point<std::chrono::steady_clock> start_time_;
 
   std::vector<char> read_buff_;
   size_t read_buff_off_ = 0;
@@ -3395,11 +3385,12 @@ class SSLSocketStream final : public Stream {
       time_t read_timeout_usec, time_t write_timeout_sec,
       time_t write_timeout_usec, time_t max_timeout_msec = 0,
       std::chrono::time_point<std::chrono::steady_clock> start_time =
-          std::chrono::steady_clock::time_point::min());
+          (std::chrono::steady_clock::time_point::min)());
   ~SSLSocketStream() override;
 
   bool is_readable() const override;
-  bool is_writable() const override;
+  bool wait_readable() const override;
+  bool wait_writable() const override;
   ssize_t read(char *ptr, size_t size) override;
   ssize_t write(const char *ptr, size_t size) override;
   void get_remote_ip_and_port(std::string &ip, int &port) const override;
@@ -3415,7 +3406,7 @@ class SSLSocketStream final : public Stream {
   time_t write_timeout_sec_;
   time_t write_timeout_usec_;
   time_t max_timeout_msec_;
-  const std::chrono::time_point<std::chrono::steady_clock> start_time;
+  const std::chrono::time_point<std::chrono::steady_clock> start_time_;
 };
 #endif
 
@@ -3550,7 +3541,6 @@ socket_t create_socket(const std::string &host, const std::string &ip, int port,
     hints.ai_flags = socket_flags;
   }
 
-#ifndef _WIN32
   if (hints.ai_family == AF_UNIX) {
     const auto addrlen = host.length();
     if (addrlen > sizeof(sockaddr_un::sun_path)) { return INVALID_SOCKET; }
@@ -3574,11 +3564,19 @@ socket_t create_socket(const std::string &host, const std::string &ip, int port,
           sizeof(addr) - sizeof(addr.sun_path) + addrlen);
 
 #ifndef SOCK_CLOEXEC
+#ifndef _WIN32
       fcntl(sock, F_SETFD, FD_CLOEXEC);
+#endif
 #endif
 
       if (socket_options) { socket_options(sock); }
 
+#ifdef _WIN32
+      // Setting SO_REUSEADDR seems not to work well with AF_UNIX on windows, so
+      // remove the option.
+      detail::set_socket_opt(sock, SOL_SOCKET, SO_REUSEADDR, 0);
+#endif
+
       bool dummy;
       if (!bind_or_connect(sock, hints, dummy)) {
         close_socket(sock);
@@ -3587,7 +3585,6 @@ socket_t create_socket(const std::string &host, const std::string &ip, int port,
     }
     return sock;
   }
-#endif
 
   auto service = std::to_string(port);
 
@@ -3993,6 +3990,12 @@ inline EncodingType encoding_type(const Request &req, const Response &res) {
   if (ret) { return EncodingType::Gzip; }
 #endif
 
+#ifdef CPPHTTPLIB_ZSTD_SUPPORT
+  // TODO: 'Accept-Encoding' has zstd, not zstd;q=0
+  ret = s.find("zstd") != std::string::npos;
+  if (ret) { return EncodingType::Zstd; }
+#endif
+
   return EncodingType::None;
 }
 
@@ -4201,6 +4204,61 @@ inline bool brotli_decompressor::decompress(const char *data,
 }
 #endif
 
+#ifdef CPPHTTPLIB_ZSTD_SUPPORT
+inline zstd_compressor::zstd_compressor() {
+  ctx_ = ZSTD_createCCtx();
+  ZSTD_CCtx_setParameter(ctx_, ZSTD_c_compressionLevel, ZSTD_fast);
+}
+
+inline zstd_compressor::~zstd_compressor() { ZSTD_freeCCtx(ctx_); }
+
+inline bool zstd_compressor::compress(const char *data, size_t data_length,
+                                      bool last, Callback callback) {
+  std::array<char, CPPHTTPLIB_COMPRESSION_BUFSIZ> buff{};
+
+  ZSTD_EndDirective mode = last ? ZSTD_e_end : ZSTD_e_continue;
+  ZSTD_inBuffer input = {data, data_length, 0};
+
+  bool finished;
+  do {
+    ZSTD_outBuffer output = {buff.data(), CPPHTTPLIB_COMPRESSION_BUFSIZ, 0};
+    size_t const remaining = ZSTD_compressStream2(ctx_, &output, &input, mode);
+
+    if (ZSTD_isError(remaining)) { return false; }
+
+    if (!callback(buff.data(), output.pos)) { return false; }
+
+    finished = last ? (remaining == 0) : (input.pos == input.size);
+
+  } while (!finished);
+
+  return true;
+}
+
+inline zstd_decompressor::zstd_decompressor() { ctx_ = ZSTD_createDCtx(); }
+
+inline zstd_decompressor::~zstd_decompressor() { ZSTD_freeDCtx(ctx_); }
+
+inline bool zstd_decompressor::is_valid() const { return ctx_ != nullptr; }
+
+inline bool zstd_decompressor::decompress(const char *data, size_t data_length,
+                                          Callback callback) {
+  std::array<char, CPPHTTPLIB_COMPRESSION_BUFSIZ> buff{};
+  ZSTD_inBuffer input = {data, data_length, 0};
+
+  while (input.pos < input.size) {
+    ZSTD_outBuffer output = {buff.data(), CPPHTTPLIB_COMPRESSION_BUFSIZ, 0};
+    size_t const remaining = ZSTD_decompressStream(ctx_, &output, &input);
+
+    if (ZSTD_isError(remaining)) { return false; }
+
+    if (!callback(buff.data(), output.pos)) { return false; }
+  }
+
+  return true;
+}
+#endif
+
 inline bool has_header(const Headers &headers, const std::string &key) {
   return headers.find(key) != headers.end();
 }
@@ -4227,6 +4285,9 @@ inline bool parse_header(const char *beg, const char *end, T fn) {
     p++;
   }
 
+  auto name = std::string(beg, p);
+  if (!detail::fields::is_field_name(name)) { return false; }
+
   if (p == end) { return false; }
 
   auto key_end = p;
@@ -4242,10 +4303,6 @@ inline bool parse_header(const char *beg, const char *end, T fn) {
     if (!key_len) { return false; }
 
     auto key = std::string(beg, key_end);
-    // auto val = (case_ignore::equal(key, "Location") ||
-    //             case_ignore::equal(key, "Referer"))
-    //                ? std::string(p, end)
-    //                : decode_url(std::string(p, end), false);
     auto val = std::string(p, end);
 
     if (!detail::fields::is_field_value(val)) { return false; }
@@ -4341,7 +4398,8 @@ inline bool read_content_without_length(Stream &strm,
   uint64_t r = 0;
   for (;;) {
     auto n = strm.read(buf, CPPHTTPLIB_RECV_BUFSIZ);
-    if (n <= 0) { return false; }
+    if (n == 0) { return true; }
+    if (n < 0) { return false; }
 
     if (!out(buf, static_cast<size_t>(n), r, 0)) { return false; }
     r += static_cast<uint64_t>(n);
@@ -4384,7 +4442,7 @@ inline bool read_content_chunked(Stream &strm, T &x,
 
   assert(chunk_len == 0);
 
-  // NOTE: In RFC 9112, '7.1 Chunked Transfer Coding' mentiones "The chunked
+  // NOTE: In RFC 9112, '7.1 Chunked Transfer Coding' mentions "The chunked
   // transfer coding is complete when a chunk with a chunk-size of zero is
   // received, possibly followed by a trailer section, and finally terminated by
   // an empty line". https://www.rfc-editor.org/rfc/rfc9112.html#section-7.1
@@ -4394,8 +4452,8 @@ inline bool read_content_chunked(Stream &strm, T &x,
   // to be ok whether the final CRLF exists or not in the chunked data.
   // https://www.rfc-editor.org/rfc/rfc9112.html#section-7.1.3
   //
-  // According to the reference code in RFC 9112, cpp-htpplib now allows
-  // chuncked transfer coding data without the final CRLF.
+  // According to the reference code in RFC 9112, cpp-httplib now allows
+  // chunked transfer coding data without the final CRLF.
   if (!line_reader.getline()) { return true; }
 
   while (strcmp(line_reader.ptr(), "\r\n") != 0) {
@@ -4442,6 +4500,13 @@ bool prepare_content_receiver(T &x, int &status,
 #else
       status = StatusCode::UnsupportedMediaType_415;
       return false;
+#endif
+    } else if (encoding == "zstd") {
+#ifdef CPPHTTPLIB_ZSTD_SUPPORT
+      decompressor = detail::make_unique<zstd_decompressor>();
+#else
+      status = StatusCode::UnsupportedMediaType_415;
+      return false;
 #endif
     }
 
@@ -4565,7 +4630,7 @@ inline bool write_content(Stream &strm, const ContentProvider &content_provider,
 
   data_sink.write = [&](const char *d, size_t l) -> bool {
     if (ok) {
-      if (strm.is_writable() && write_data(strm, d, l)) {
+      if (write_data(strm, d, l)) {
         offset += l;
       } else {
         ok = false;
@@ -4574,10 +4639,10 @@ inline bool write_content(Stream &strm, const ContentProvider &content_provider,
     return ok;
   };
 
-  data_sink.is_writable = [&]() -> bool { return strm.is_writable(); };
+  data_sink.is_writable = [&]() -> bool { return strm.wait_writable(); };
 
   while (offset < end_offset && !is_shutting_down()) {
-    if (!strm.is_writable()) {
+    if (!strm.wait_writable()) {
       error = Error::Write;
       return false;
     } else if (!content_provider(offset, end_offset - offset, data_sink)) {
@@ -4615,17 +4680,17 @@ write_content_without_length(Stream &strm,
   data_sink.write = [&](const char *d, size_t l) -> bool {
     if (ok) {
       offset += l;
-      if (!strm.is_writable() || !write_data(strm, d, l)) { ok = false; }
+      if (!write_data(strm, d, l)) { ok = false; }
     }
     return ok;
   };
 
-  data_sink.is_writable = [&]() -> bool { return strm.is_writable(); };
+  data_sink.is_writable = [&]() -> bool { return strm.wait_writable(); };
 
   data_sink.done = [&](void) { data_available = false; };
 
   while (data_available && !is_shutting_down()) {
-    if (!strm.is_writable()) {
+    if (!strm.wait_writable()) {
       return false;
     } else if (!content_provider(offset, 0, data_sink)) {
       return false;
@@ -4660,10 +4725,7 @@ write_content_chunked(Stream &strm, const ContentProvider &content_provider,
           // Emit chunked response header and footer for each chunk
           auto chunk =
               from_i_to_hex(payload.size()) + "\r\n" + payload + "\r\n";
-          if (!strm.is_writable() ||
-              !write_data(strm, chunk.data(), chunk.size())) {
-            ok = false;
-          }
+          if (!write_data(strm, chunk.data(), chunk.size())) { ok = false; }
         }
       } else {
         ok = false;
@@ -4672,7 +4734,7 @@ write_content_chunked(Stream &strm, const ContentProvider &content_provider,
     return ok;
   };
 
-  data_sink.is_writable = [&]() -> bool { return strm.is_writable(); };
+  data_sink.is_writable = [&]() -> bool { return strm.wait_writable(); };
 
   auto done_with_trailer = [&](const Headers *trailer) {
     if (!ok) { return; }
@@ -4692,17 +4754,14 @@ write_content_chunked(Stream &strm, const ContentProvider &content_provider,
     if (!payload.empty()) {
       // Emit chunked response header and footer for each chunk
       auto chunk = from_i_to_hex(payload.size()) + "\r\n" + payload + "\r\n";
-      if (!strm.is_writable() ||
-          !write_data(strm, chunk.data(), chunk.size())) {
+      if (!write_data(strm, chunk.data(), chunk.size())) {
         ok = false;
         return;
       }
     }
 
-    static const std::string done_marker("0\r\n");
-    if (!write_data(strm, done_marker.data(), done_marker.size())) {
-      ok = false;
-    }
+    constexpr const char done_marker[] = "0\r\n";
+    if (!write_data(strm, done_marker, str_len(done_marker))) { ok = false; }
 
     // Trailer
     if (trailer) {
@@ -4714,8 +4773,8 @@ write_content_chunked(Stream &strm, const ContentProvider &content_provider,
       }
     }
 
-    static const std::string crlf("\r\n");
-    if (!write_data(strm, crlf.data(), crlf.size())) { ok = false; }
+    constexpr const char crlf[] = "\r\n";
+    if (!write_data(strm, crlf, str_len(crlf))) { ok = false; }
   };
 
   data_sink.done = [&](void) { done_with_trailer(nullptr); };
@@ -4725,7 +4784,7 @@ write_content_chunked(Stream &strm, const ContentProvider &content_provider,
   };
 
   while (data_available && !is_shutting_down()) {
-    if (!strm.is_writable()) {
+    if (!strm.wait_writable()) {
       error = Error::Write;
       return false;
     } else if (!content_provider(offset, 0, data_sink)) {
@@ -4957,13 +5016,13 @@ class MultipartFormDataParser {
             return false;
           }
 
-          static const std::string header_content_type = "Content-Type:";
+          constexpr const char header_content_type[] = "Content-Type:";
 
           if (start_with_case_ignore(header, header_content_type)) {
             file_.content_type =
-                trim_copy(header.substr(header_content_type.size()));
+                trim_copy(header.substr(str_len(header_content_type)));
           } else {
-            static const std::regex re_content_disposition(
+            thread_local const std::regex re_content_disposition(
                 R"~(^Content-Disposition:\s*form-data;\s*(.*)$)~",
                 std::regex_constants::icase);
 
@@ -4985,8 +5044,8 @@ class MultipartFormDataParser {
 
               it = params.find("filename*");
               if (it != params.end()) {
-                // Only allow UTF-8 enconnding...
-                static const std::regex re_rfc5987_encoding(
+                // Only allow UTF-8 encoding...
+                thread_local const std::regex re_rfc5987_encoding(
                     R"~(^UTF-8''(.+?)$)~", std::regex_constants::icase);
 
                 std::smatch m2;
@@ -5058,10 +5117,10 @@ class MultipartFormDataParser {
     file_.content_type.clear();
   }
 
-  bool start_with_case_ignore(const std::string &a,
-                              const std::string &b) const {
-    if (a.size() < b.size()) { return false; }
-    for (size_t i = 0; i < b.size(); i++) {
+  bool start_with_case_ignore(const std::string &a, const char *b) const {
+    const auto b_len = strlen(b);
+    if (a.size() < b_len) { return false; }
+    for (size_t i = 0; i < b_len; i++) {
       if (case_ignore::to_lower(a[i]) != case_ignore::to_lower(b[i])) {
         return false;
       }
@@ -5148,19 +5207,18 @@ class MultipartFormDataParser {
 };
 
 inline std::string random_string(size_t length) {
-  static const char data[] =
+  constexpr const char data[] =
       "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
 
-  // std::random_device might actually be deterministic on some
-  // platforms, but due to lack of support in the c++ standard library,
-  // doing better requires either some ugly hacks or breaking portability.
-  static std::random_device seed_gen;
-
-  // Request 128 bits of entropy for initialization
-  static std::seed_seq seed_sequence{seed_gen(), seed_gen(), seed_gen(),
-                                     seed_gen()};
-
-  static std::mt19937 engine(seed_sequence);
+  thread_local auto engine([]() {
+    // std::random_device might actually be deterministic on some
+    // platforms, but due to lack of support in the c++ standard library,
+    // doing better requires either some ugly hacks or breaking portability.
+    std::random_device seed_gen;
+    // Request 128 bits of entropy for initialization
+    std::seed_seq seed_sequence{seed_gen(), seed_gen(), seed_gen(), seed_gen()};
+    return std::mt19937(seed_sequence);
+  }());
 
   std::string result;
   for (size_t i = 0; i < length; i++) {
@@ -5232,7 +5290,7 @@ serialize_multipart_formdata(const MultipartFormDataItems &items,
 
 inline bool range_error(Request &req, Response &res) {
   if (!req.ranges.empty() && 200 <= res.status && res.status < 300) {
-    ssize_t contant_len = static_cast<ssize_t>(
+    ssize_t content_len = static_cast<ssize_t>(
         res.content_length_ ? res.content_length_ : res.body.size());
 
     ssize_t prev_first_pos = -1;
@@ -5252,12 +5310,12 @@ inline bool range_error(Request &req, Response &res) {
 
       if (first_pos == -1 && last_pos == -1) {
         first_pos = 0;
-        last_pos = contant_len;
+        last_pos = content_len;
       }
 
       if (first_pos == -1) {
-        first_pos = contant_len - last_pos;
-        last_pos = contant_len - 1;
+        first_pos = content_len - last_pos;
+        last_pos = content_len - 1;
       }
 
       // NOTE: RFC-9110 '14.1.2. Byte Ranges':
@@ -5269,13 +5327,13 @@ inline bool range_error(Request &req, Response &res) {
       // with a value that is one less than the current length of the selected
       // representation).
       // https://www.rfc-editor.org/rfc/rfc9110.html#section-14.1.2-6
-      if (last_pos == -1 || last_pos >= contant_len) {
-        last_pos = contant_len - 1;
+      if (last_pos == -1 || last_pos >= content_len) {
+        last_pos = content_len - 1;
       }
 
       // Range must be within content length
       if (!(0 <= first_pos && first_pos <= last_pos &&
-            last_pos <= contant_len - 1)) {
+            last_pos <= content_len - 1)) {
         return true;
       }
 
@@ -5674,7 +5732,8 @@ inline bool parse_www_authenticate(const Response &res,
                                    bool is_proxy) {
   auto auth_key = is_proxy ? "Proxy-Authenticate" : "WWW-Authenticate";
   if (res.has_header(auth_key)) {
-    static auto re = std::regex(R"~((?:(?:,\s*)?(.+?)=(?:"(.*?)"|([^,]*))))~");
+    thread_local auto re =
+        std::regex(R"~((?:(?:,\s*)?(.+?)=(?:"(.*?)"|([^,]*))))~");
     auto s = res.get_header_value(auth_key);
     auto pos = s.find(' ');
     if (pos != std::string::npos) {
@@ -5758,7 +5817,7 @@ inline void hosted_at(const std::string &hostname,
 inline std::string append_query_params(const std::string &path,
                                        const Params &params) {
   std::string path_with_query = path;
-  const static std::regex re("[^?]+\\?.*");
+  thread_local const std::regex re("[^?]+\\?.*");
   auto delm = std::regex_match(path, re) ? '&' : '?';
   path_with_query += delm + detail::params_to_query_str(params);
   return path_with_query;
@@ -5987,14 +6046,14 @@ inline ssize_t Stream::write(const std::string &s) {
 
 namespace detail {
 
-inline void calc_actual_timeout(time_t max_timeout_msec,
-                                time_t duration_msec, time_t timeout_sec,
-                                time_t timeout_usec, time_t &actual_timeout_sec,
+inline void calc_actual_timeout(time_t max_timeout_msec, time_t duration_msec,
+                                time_t timeout_sec, time_t timeout_usec,
+                                time_t &actual_timeout_sec,
                                 time_t &actual_timeout_usec) {
   auto timeout_msec = (timeout_sec * 1000) + (timeout_usec / 1000);
 
   auto actual_timeout_msec =
-      std::min(max_timeout_msec - duration_msec, timeout_msec);
+      (std::min)(max_timeout_msec - duration_msec, timeout_msec);
 
   actual_timeout_sec = actual_timeout_msec / 1000;
   actual_timeout_usec = (actual_timeout_msec % 1000) * 1000;
@@ -6010,12 +6069,16 @@ inline SocketStream::SocketStream(
       read_timeout_usec_(read_timeout_usec),
       write_timeout_sec_(write_timeout_sec),
       write_timeout_usec_(write_timeout_usec),
-      max_timeout_msec_(max_timeout_msec), start_time(start_time),
+      max_timeout_msec_(max_timeout_msec), start_time_(start_time),
       read_buff_(read_buff_size_, 0) {}
 
 inline SocketStream::~SocketStream() = default;
 
 inline bool SocketStream::is_readable() const {
+  return read_buff_off_ < read_buff_content_size_;
+}
+
+inline bool SocketStream::wait_readable() const {
   if (max_timeout_msec_ <= 0) {
     return select_read(sock_, read_timeout_sec_, read_timeout_usec_) > 0;
   }
@@ -6028,7 +6091,7 @@ inline bool SocketStream::is_readable() const {
   return select_read(sock_, read_timeout_sec, read_timeout_usec) > 0;
 }
 
-inline bool SocketStream::is_writable() const {
+inline bool SocketStream::wait_writable() const {
   return select_write(sock_, write_timeout_sec_, write_timeout_usec_) > 0 &&
          is_socket_alive(sock_);
 }
@@ -6055,7 +6118,7 @@ inline ssize_t SocketStream::read(char *ptr, size_t size) {
     }
   }
 
-  if (!is_readable()) { return -1; }
+  if (!wait_readable()) { return -1; }
 
   read_buff_off_ = 0;
   read_buff_content_size_ = 0;
@@ -6080,7 +6143,7 @@ inline ssize_t SocketStream::read(char *ptr, size_t size) {
 }
 
 inline ssize_t SocketStream::write(const char *ptr, size_t size) {
-  if (!is_writable()) { return -1; }
+  if (!wait_writable()) { return -1; }
 
 #if defined(_WIN32) && !defined(_WIN64)
   size =
@@ -6104,14 +6167,16 @@ inline socket_t SocketStream::socket() const { return sock_; }
 
 inline time_t SocketStream::duration() const {
   return std::chrono::duration_cast<std::chrono::milliseconds>(
-             std::chrono::steady_clock::now() - start_time)
+             std::chrono::steady_clock::now() - start_time_)
       .count();
 }
 
 // Buffer stream implementation
 inline bool BufferStream::is_readable() const { return true; }
 
-inline bool BufferStream::is_writable() const { return true; }
+inline bool BufferStream::wait_readable() const { return true; }
+
+inline bool BufferStream::wait_writable() const { return true; }
 
 inline ssize_t BufferStream::read(char *ptr, size_t size) {
 #if defined(_MSC_VER) && _MSC_VER < 1910
@@ -6141,7 +6206,7 @@ inline time_t BufferStream::duration() const { return 0; }
 inline const std::string &BufferStream::get_buffer() const { return buffer; }
 
 inline PathParamsMatcher::PathParamsMatcher(const std::string &pattern) {
-  static constexpr char marker[] = "/:";
+  constexpr const char marker[] = "/:";
 
   // One past the last ending position of a path param substring
   std::size_t last_param_end = 0;
@@ -6162,7 +6227,7 @@ inline PathParamsMatcher::PathParamsMatcher(const std::string &pattern) {
     static_fragments_.push_back(
         pattern.substr(last_param_end, marker_pos - last_param_end + 1));
 
-    const auto param_name_start = marker_pos + 2;
+    const auto param_name_start = marker_pos + str_len(marker);
 
     auto sep_pos = pattern.find(separator, param_name_start);
     if (sep_pos == std::string::npos) { sep_pos = pattern.length(); }
@@ -6469,12 +6534,12 @@ inline Server &Server::set_payload_max_length(size_t length) {
 inline bool Server::bind_to_port(const std::string &host, int port,
                                  int socket_flags) {
   auto ret = bind_internal(host, port, socket_flags);
-  if (ret == -1) { is_decommisioned = true; }
+  if (ret == -1) { is_decommissioned = true; }
   return ret >= 0;
 }
 inline int Server::bind_to_any_port(const std::string &host, int socket_flags) {
   auto ret = bind_internal(host, 0, socket_flags);
-  if (ret == -1) { is_decommisioned = true; }
+  if (ret == -1) { is_decommissioned = true; }
   return ret;
 }
 
@@ -6488,7 +6553,7 @@ inline bool Server::listen(const std::string &host, int port,
 inline bool Server::is_running() const { return is_running_; }
 
 inline void Server::wait_until_ready() const {
-  while (!is_running_ && !is_decommisioned) {
+  while (!is_running_ && !is_decommissioned) {
     std::this_thread::sleep_for(std::chrono::milliseconds{1});
   }
 }
@@ -6500,10 +6565,10 @@ inline void Server::stop() {
     detail::shutdown_socket(sock);
     detail::close_socket(sock);
   }
-  is_decommisioned = false;
+  is_decommissioned = false;
 }
 
-inline void Server::decommission() { is_decommisioned = true; }
+inline void Server::decommission() { is_decommissioned = true; }
 
 inline bool Server::parse_request_line(const char *s, Request &req) const {
   auto len = strlen(s);
@@ -6526,7 +6591,7 @@ inline bool Server::parse_request_line(const char *s, Request &req) const {
     if (count != 3) { return false; }
   }
 
-  static const std::set<std::string> methods{
+  thread_local const std::set<std::string> methods{
       "GET",     "HEAD",    "POST",  "PUT",   "DELETE",
       "CONNECT", "OPTIONS", "TRACE", "PATCH", "PRI"};
 
@@ -6680,6 +6745,10 @@ Server::write_content_with_provider(Stream &strm, const Request &req,
       } else if (type == detail::EncodingType::Brotli) {
 #ifdef CPPHTTPLIB_BROTLI_SUPPORT
         compressor = detail::make_unique<detail::brotli_compressor>();
+#endif
+      } else if (type == detail::EncodingType::Zstd) {
+#ifdef CPPHTTPLIB_ZSTD_SUPPORT
+        compressor = detail::make_unique<detail::zstd_compressor>();
 #endif
       } else {
         compressor = detail::make_unique<detail::nocompressor>();
@@ -6862,7 +6931,7 @@ Server::create_server_socket(const std::string &host, int port,
 
 inline int Server::bind_internal(const std::string &host, int port,
                                  int socket_flags) {
-  if (is_decommisioned) { return -1; }
+  if (is_decommissioned) { return -1; }
 
   if (!is_valid()) { return -1; }
 
@@ -6889,7 +6958,7 @@ inline int Server::bind_internal(const std::string &host, int port,
 }
 
 inline bool Server::listen_internal() {
-  if (is_decommisioned) { return false; }
+  if (is_decommissioned) { return false; }
 
   auto ret = true;
   is_running_ = true;
@@ -6913,7 +6982,7 @@ inline bool Server::listen_internal() {
 #endif
 
 #if defined _WIN32
-      // sockets conneced via WASAccept inherit flags NO_HANDLE_INHERIT,
+      // sockets connected via WASAccept inherit flags NO_HANDLE_INHERIT,
       // OVERLAPPED
       socket_t sock = WSAAccept(svr_sock_, nullptr, nullptr, nullptr, 0);
 #elif defined SOCK_CLOEXEC
@@ -6955,7 +7024,7 @@ inline bool Server::listen_internal() {
     task_queue->shutdown();
   }
 
-  is_decommisioned = !ret;
+  is_decommissioned = !ret;
   return ret;
 }
 
@@ -7095,6 +7164,8 @@ inline void Server::apply_ranges(const Request &req, Response &res,
             res.set_header("Content-Encoding", "gzip");
           } else if (type == detail::EncodingType::Brotli) {
             res.set_header("Content-Encoding", "br");
+          } else if (type == detail::EncodingType::Zstd) {
+            res.set_header("Content-Encoding", "zstd");
           }
         }
       }
@@ -7134,6 +7205,11 @@ inline void Server::apply_ranges(const Request &req, Response &res,
 #ifdef CPPHTTPLIB_BROTLI_SUPPORT
         compressor = detail::make_unique<detail::brotli_compressor>();
         content_encoding = "br";
+#endif
+      } else if (type == detail::EncodingType::Zstd) {
+#ifdef CPPHTTPLIB_ZSTD_SUPPORT
+        compressor = detail::make_unique<detail::zstd_compressor>();
+        content_encoding = "zstd";
 #endif
       }
 
@@ -7189,20 +7265,6 @@ Server::process_request(Stream &strm, const std::string &remote_addr,
   res.version = "HTTP/1.1";
   res.headers = default_headers_;
 
-#ifdef _WIN32
-  // TODO: Increase FD_SETSIZE statically (libzmq), dynamically (MySQL).
-#else
-#ifndef CPPHTTPLIB_USE_POLL
-  // Socket file descriptor exceeded FD_SETSIZE...
-  if (strm.socket() >= FD_SETSIZE) {
-    Headers dummy;
-    detail::read_headers(strm, dummy);
-    res.status = StatusCode::InternalServerError_500;
-    return write_response(strm, close_connection, req, res);
-  }
-#endif
-#endif
-
   // Request line and headers
   if (!parse_request_line(line_reader.ptr(), req) ||
       !detail::read_headers(strm, req.headers)) {
@@ -7394,6 +7456,16 @@ inline ClientImpl::ClientImpl(const std::string &host, int port,
       client_cert_path_(client_cert_path), client_key_path_(client_key_path) {}
 
 inline ClientImpl::~ClientImpl() {
+  // Wait until all the requests in flight are handled.
+  size_t retry_count = 10;
+  while (retry_count-- > 0) {
+    {
+      std::lock_guard<std::mutex> guard(socket_mutex_);
+      if (socket_requests_in_flight_ == 0) { break; }
+    }
+    std::this_thread::sleep_for(std::chrono::milliseconds{1});
+  }
+
   std::lock_guard<std::mutex> guard(socket_mutex_);
   shutdown_socket(socket_);
   close_socket(socket_);
@@ -7519,9 +7591,9 @@ inline bool ClientImpl::read_response_line(Stream &strm, const Request &req,
   if (!line_reader.getline()) { return false; }
 
 #ifdef CPPHTTPLIB_ALLOW_LF_AS_LINE_TERMINATOR
-  const static std::regex re("(HTTP/1\\.[01]) (\\d{3})(?: (.*?))?\r?\n");
+  thread_local const std::regex re("(HTTP/1\\.[01]) (\\d{3})(?: (.*?))?\r?\n");
 #else
-  const static std::regex re("(HTTP/1\\.[01]) (\\d{3})(?: (.*?))?\r\n");
+  thread_local const std::regex re("(HTTP/1\\.[01]) (\\d{3})(?: (.*?))?\r\n");
 #endif
 
   std::cmatch m;
@@ -7577,7 +7649,7 @@ inline bool ClientImpl::send_(Request &req, Response &res, Error &error) {
 #endif
 
       if (!is_alive) {
-        // Attempt to avoid sigpipe by shutting down nongracefully if it seems
+        // Attempt to avoid sigpipe by shutting down non-gracefully if it seems
         // like the other side has already closed the connection Also, there
         // cannot be any requests in flight from other threads since we locked
         // request_mutex_, so safe to close everything immediately
@@ -7753,7 +7825,7 @@ inline bool ClientImpl::redirect(Request &req, Response &res, Error &error) {
   auto location = res.get_header_value("location");
   if (location.empty()) { return false; }
 
-  const static std::regex re(
+  thread_local const std::regex re(
       R"((?:(https?):)?(?://(?:\[([a-fA-F\d:]+)\]|([^:/?#]+))(?::(\d+))?)?([^?#]*)(\?[^#]*)?(?:#.*)?)");
 
   std::smatch m;
@@ -7862,6 +7934,10 @@ inline bool ClientImpl::write_request(Stream &strm, Request &req,
 #ifdef CPPHTTPLIB_ZLIB_SUPPORT
       if (!accept_encoding.empty()) { accept_encoding += ", "; }
       accept_encoding += "gzip, deflate";
+#endif
+#ifdef CPPHTTPLIB_ZSTD_SUPPORT
+      if (!accept_encoding.empty()) { accept_encoding += ", "; }
+      accept_encoding += "zstd";
 #endif
       req.set_header("Accept-Encoding", accept_encoding);
     }
@@ -8213,8 +8289,7 @@ inline bool ClientImpl::process_socket(
     std::function<bool(Stream &strm)> callback) {
   return detail::process_client_socket(
       socket.sock, read_timeout_sec_, read_timeout_usec_, write_timeout_sec_,
-      write_timeout_usec_, max_timeout_msec_, start_time,
-      std::move(callback));
+      write_timeout_usec_, max_timeout_msec_, start_time, std::move(callback));
 }
 
 inline bool ClientImpl::is_ssl() const { return false; }
@@ -9009,7 +9084,7 @@ inline void ClientImpl::enable_server_hostname_verification(bool enabled) {
 }
 
 inline void ClientImpl::set_server_certificate_verifier(
-    std::function<bool(SSL *ssl)> verifier) {
+    std::function<SSLVerifierResponse(SSL *ssl)> verifier) {
   server_certificate_verifier_ = verifier;
 }
 #endif
@@ -9062,18 +9137,13 @@ inline void ssl_delete(std::mutex &ctx_mutex, SSL *ssl, socket_t sock,
   // Note that it is not always possible to avoid SIGPIPE, this is merely a
   // best-efforts.
   if (shutdown_gracefully) {
-#ifdef _WIN32
     (void)(sock);
-    SSL_shutdown(ssl);
-#else
-    detail::set_socket_opt_time(sock, SOL_SOCKET, SO_RCVTIMEO, 1, 0);
-
-    auto ret = SSL_shutdown(ssl);
-    while (ret == 0) {
-      std::this_thread::sleep_for(std::chrono::milliseconds{100});
-      ret = SSL_shutdown(ssl);
+    // SSL_shutdown() returns 0 on first call (indicating close_notify alert
+    // sent) and 1 on subsequent call (indicating close_notify alert received)
+    if (SSL_shutdown(ssl) == 0) {
+      // Expected to return 1, but even if it doesn't, we free ssl
+      SSL_shutdown(ssl);
     }
-#endif
   }
 
   std::lock_guard<std::mutex> guard(ctx_mutex);
@@ -9124,19 +9194,11 @@ inline bool process_client_socket_ssl(
     time_t max_timeout_msec,
     std::chrono::time_point<std::chrono::steady_clock> start_time, T callback) {
   SSLSocketStream strm(sock, ssl, read_timeout_sec, read_timeout_usec,
-                       write_timeout_sec, write_timeout_usec,
-                       max_timeout_msec, start_time);
+                       write_timeout_sec, write_timeout_usec, max_timeout_msec,
+                       start_time);
   return callback(strm);
 }
 
-class SSLInit {
-public:
-  SSLInit() {
-    OPENSSL_init_ssl(
-        OPENSSL_INIT_LOAD_SSL_STRINGS | OPENSSL_INIT_LOAD_CRYPTO_STRINGS, NULL);
-  }
-};
-
 // SSL socket stream implementation
 inline SSLSocketStream::SSLSocketStream(
     socket_t sock, SSL *ssl, time_t read_timeout_sec, time_t read_timeout_usec,
@@ -9147,13 +9209,17 @@ inline SSLSocketStream::SSLSocketStream(
       read_timeout_usec_(read_timeout_usec),
       write_timeout_sec_(write_timeout_sec),
       write_timeout_usec_(write_timeout_usec),
-      max_timeout_msec_(max_timeout_msec), start_time(start_time) {
+      max_timeout_msec_(max_timeout_msec), start_time_(start_time) {
   SSL_clear_mode(ssl, SSL_MODE_AUTO_RETRY);
 }
 
 inline SSLSocketStream::~SSLSocketStream() = default;
 
 inline bool SSLSocketStream::is_readable() const {
+  return SSL_pending(ssl_) > 0;
+}
+
+inline bool SSLSocketStream::wait_readable() const {
   if (max_timeout_msec_ <= 0) {
     return select_read(sock_, read_timeout_sec_, read_timeout_usec_) > 0;
   }
@@ -9166,15 +9232,15 @@ inline bool SSLSocketStream::is_readable() const {
   return select_read(sock_, read_timeout_sec, read_timeout_usec) > 0;
 }
 
-inline bool SSLSocketStream::is_writable() const {
+inline bool SSLSocketStream::wait_writable() const {
   return select_write(sock_, write_timeout_sec_, write_timeout_usec_) > 0 &&
          is_socket_alive(sock_) && !is_ssl_peer_could_be_closed(ssl_, sock_);
 }
 
 inline ssize_t SSLSocketStream::read(char *ptr, size_t size) {
   if (SSL_pending(ssl_) > 0) {
     return SSL_read(ssl_, ptr, static_cast<int>(size));
-  } else if (is_readable()) {
+  } else if (wait_readable()) {
     auto ret = SSL_read(ssl_, ptr, static_cast<int>(size));
     if (ret < 0) {
       auto err = SSL_get_error(ssl_, ret);
@@ -9188,7 +9254,7 @@ inline ssize_t SSLSocketStream::read(char *ptr, size_t size) {
 #endif
         if (SSL_pending(ssl_) > 0) {
           return SSL_read(ssl_, ptr, static_cast<int>(size));
-        } else if (is_readable()) {
+        } else if (wait_readable()) {
           std::this_thread::sleep_for(std::chrono::microseconds{10});
           ret = SSL_read(ssl_, ptr, static_cast<int>(size));
           if (ret >= 0) { return ret; }
@@ -9205,7 +9271,7 @@ inline ssize_t SSLSocketStream::read(char *ptr, size_t size) {
 }
 
 inline ssize_t SSLSocketStream::write(const char *ptr, size_t size) {
-  if (is_writable()) {
+  if (wait_writable()) {
     auto handle_size = static_cast<int>(
         std::min<size_t>(size, (std::numeric_limits<int>::max)()));
 
@@ -9220,7 +9286,7 @@ inline ssize_t SSLSocketStream::write(const char *ptr, size_t size) {
 #else
       while (--n >= 0 && err == SSL_ERROR_WANT_WRITE) {
 #endif
-        if (is_writable()) {
+        if (wait_writable()) {
           std::this_thread::sleep_for(std::chrono::microseconds{10});
           ret = SSL_write(ssl_, ptr, static_cast<int>(handle_size));
           if (ret >= 0) { return ret; }
@@ -9249,12 +9315,10 @@ inline socket_t SSLSocketStream::socket() const { return sock_; }
 
 inline time_t SSLSocketStream::duration() const {
   return std::chrono::duration_cast<std::chrono::milliseconds>(
-             std::chrono::steady_clock::now() - start_time)
+             std::chrono::steady_clock::now() - start_time_)
       .count();
 }
 
-static SSLInit sslinit_;
-
 } // namespace detail
 
 // SSL HTTP server implementation
@@ -9623,12 +9687,18 @@ inline bool SSLClient::initialize_ssl(Socket &socket, Error &error) {
         }
 
         if (server_certificate_verification_) {
+          auto verification_status = SSLVerifierResponse::NoDecisionMade;
+
           if (server_certificate_verifier_) {
-            if (!server_certificate_verifier_(ssl2)) {
-              error = Error::SSLServerVerification;
-              return false;
-            }
-          } else {
+            verification_status = server_certificate_verifier_(ssl2);
+          }
+
+          if (verification_status == SSLVerifierResponse::CertificateRejected) {
+            error = Error::SSLServerVerification;
+            return false;
+          }
+
+          if (verification_status == SSLVerifierResponse::NoDecisionMade) {
             verify_result_ = SSL_get_verify_result(ssl2);
 
             if (verify_result_ != X509_V_OK) {
@@ -9740,8 +9810,8 @@ SSLClient::verify_host_with_subject_alt_name(X509 *server_cert) const {
 
   auto type = GEN_DNS;
 
-  struct in6_addr addr6{};
-  struct in_addr addr{};
+  struct in6_addr addr6 = {};
+  struct in_addr addr = {};
   size_t addr_len = 0;
 
 #ifndef __MINGW32__
@@ -10389,7 +10459,7 @@ inline void Client::enable_server_hostname_verification(bool enabled) {
 }
 
 inline void Client::set_server_certificate_verifier(
-    std::function<bool(SSL *ssl)> verifier) {
+    std::function<SSLVerifierResponse(SSL *ssl)> verifier) {
   cli_->set_server_certificate_verifier(verifier);
 }
 #endif
@@ -10433,8 +10503,4 @@ inline SSL_CTX *Client::ssl_context() const {
 
 } // namespace httplib
 
-#if defined(_WIN32) && defined(CPPHTTPLIB_USE_POLL)
-#undef poll
-#endif
-
 #endif // CPPHTTPLIB_HTTPLIB_H

filename: examples/server/server.cpp
patch: @@ -4459,15 +4459,24 @@ int main(int argc, char ** argv) {
         llama_backend_free();
     };
 
-    // bind HTTP listen port
     bool was_bound = false;
-    if (params.port == 0) {
-        int bound_port = svr->bind_to_any_port(params.hostname);
-        if ((was_bound = (bound_port >= 0))) {
-            params.port = bound_port;
-        }
+    if (string_ends_with(std::string(params.hostname), ".sock")) {
+        LOG_INF("%s: setting address family to AF_UNIX\n", __func__);
+        svr->set_address_family(AF_UNIX);
+        // bind_to_port requires a second arg, any value other than 0 should
+        // simply get ignored
+        was_bound = svr->bind_to_port(params.hostname, 8080);
     } else {
-        was_bound = svr->bind_to_port(params.hostname, params.port);
+        LOG_INF("%s: binding port with default address family\n", __func__);
+        // bind HTTP listen port
+        if (params.port == 0) {
+            int bound_port = svr->bind_to_any_port(params.hostname);
+            if ((was_bound = (bound_port >= 0))) {
+                params.port = bound_port;
+            }
+        } else {
+            was_bound = svr->bind_to_port(params.hostname, params.port);
+        }
     }
 
     if (!was_bound) {