diff --git a/include/cinatra/coro_http_client.hpp b/include/cinatra/coro_http_client.hpp
index f4bfa0cf..8fc1f10f 100644
--- a/include/cinatra/coro_http_client.hpp
+++ b/include/cinatra/coro_http_client.hpp
@@ -144,11 +144,11 @@ class coro_http_client : public std::enable_shared_from_this<coro_http_client> {
   };
 
   coro_http_client(asio::io_context::executor_type executor)
-      : socket_(std::make_shared<socket_t>(executor)),
+      : executor_wrapper_(executor),
+        timer_(&executor_wrapper_),
+        socket_(std::make_shared<socket_t>(executor)),
         read_buf_(socket_->read_buf_),
-        chunked_buf_(socket_->chunked_buf_),
-        executor_wrapper_(executor),
-        timer_(&executor_wrapper_) {}
+        chunked_buf_(socket_->chunked_buf_) {}
 
   coro_http_client(
       coro_io::ExecutorWrapper<> *executor = coro_io::get_global_executor())
@@ -644,7 +644,7 @@ class coro_http_client : public std::enable_shared_from_this<coro_http_client> {
     }
     std::error_code err_code;
     timer_.cancel(err_code);
-    auto ret = co_await std::move(future);
+    co_await std::move(future);
     if (is_timeout_) {
       co_return std::make_error_code(std::errc::timed_out);
     }
@@ -752,6 +752,7 @@ class coro_http_client : public std::enable_shared_from_this<coro_http_client> {
 
     req_context<> ctx{};
     if (range.empty()) {
+      add_header("Transfer-Encoding", "chunked");
       ctx = {req_content_type::none, "", "", std::move(file)};
     }
     else {
diff --git a/include/cinatra/coro_http_connection.hpp b/include/cinatra/coro_http_connection.hpp
index 5776cf31..346aa3b9 100644
--- a/include/cinatra/coro_http_connection.hpp
+++ b/include/cinatra/coro_http_connection.hpp
@@ -88,7 +88,9 @@ class coro_http_connection
 #endif
 
   async_simple::coro::Lazy<void> start() {
+#ifdef CINATRA_ENABLE_SSL
     bool has_shake = false;
+#endif
     while (true) {
 #ifdef CINATRA_ENABLE_SSL
       if (use_ssl_ && !has_shake) {
@@ -220,6 +222,45 @@ class coro_http_connection
     co_return true;
   }
 
+  async_simple::coro::Lazy<bool> write_data(std::string_view message) {
+    std::vector<asio::const_buffer> buffers;
+    buffers.push_back(asio::buffer(message));
+    auto [ec, _] = co_await async_write(buffers);
+    if (ec) {
+      CINATRA_LOG_ERROR << "async_write error: " << ec.message();
+      close();
+      co_return false;
+    }
+
+    if (!keep_alive_) {
+      // now in io thread, so can close socket immediately.
+      close();
+    }
+
+    co_return true;
+  }
+
+  async_simple::coro::Lazy<bool> write_chunked_data(std::string_view buf,
+                                                    bool eof) {
+    std::string chunk_size_str = "";
+    std::vector<asio::const_buffer> buffers =
+        to_chunked_buffers<asio::const_buffer>(buf.data(), buf.length(),
+                                               chunk_size_str, eof);
+    auto [ec, _] = co_await async_write(std::move(buffers));
+    if (ec) {
+      CINATRA_LOG_ERROR << "async_write error: " << ec.message();
+      close();
+      co_return false;
+    }
+
+    if (!keep_alive_) {
+      // now in io thread, so can close socket immediately.
+      close();
+    }
+
+    co_return true;
+  }
+
   bool sync_reply() { return async_simple::coro::syncAwait(reply()); }
 
   async_simple::coro::Lazy<bool> begin_chunked() {
diff --git a/include/cinatra/coro_http_request.hpp b/include/cinatra/coro_http_request.hpp
index 3dfafe5e..7e3b4e60 100644
--- a/include/cinatra/coro_http_request.hpp
+++ b/include/cinatra/coro_http_request.hpp
@@ -54,6 +54,8 @@ class coro_http_request {
     return is_chunk;
   }
 
+  bool is_ranges() { return parser_.is_ranges(); }
+
   content_type get_content_type() {
     static content_type thread_local content_type = get_content_type_impl();
     return content_type;
diff --git a/include/cinatra/coro_http_server.hpp b/include/cinatra/coro_http_server.hpp
index 0a71ec28..3ba84edf 100644
--- a/include/cinatra/coro_http_server.hpp
+++ b/include/cinatra/coro_http_server.hpp
@@ -2,6 +2,7 @@
 
 #include <asio/dispatch.hpp>
 #include <cstdint>
+#include <fstream>
 #include <mutex>
 #include <type_traits>
 
@@ -10,6 +11,8 @@
 #include "async_simple/coro/Lazy.h"
 #include "cinatra/coro_http_response.hpp"
 #include "cinatra/coro_http_router.hpp"
+#include "cinatra/mime_types.hpp"
+#include "cinatra/utils.hpp"
 #include "cinatra_log_wrapper.hpp"
 #include "coro_http_connection.hpp"
 #include "ylt/coro_io/coro_io.hpp"
@@ -78,7 +81,7 @@ class coro_http_server {
       promise.setValue(ec);
     }
 
-    return std::move(future);
+    return future;
   }
 
   // only call once, not thread safe.
@@ -150,6 +153,139 @@ class coro_http_server {
     }
   }
 
+  void set_transfer_chunked_size(size_t size) { chunked_size_ = size; }
+
+  void set_static_res_handler(std::string_view uri_suffix = "",
+                              std::string file_path = "www") {
+    bool has_double_dot = (file_path.find("..") != std::string::npos) ||
+                          (uri_suffix.find("..") != std::string::npos);
+    if (std::filesystem::path(file_path).has_root_path() ||
+        std::filesystem::path(uri_suffix).has_root_path() || has_double_dot) {
+      CINATRA_LOG_ERROR << "invalid file path: " << file_path;
+      std::exit(1);
+    }
+
+    if (!uri_suffix.empty()) {
+      static_dir_router_path_ =
+          std::filesystem::path(uri_suffix).make_preferred().string();
+    }
+
+    if (!file_path.empty()) {
+      static_dir_ = std::filesystem::path(file_path).make_preferred().string();
+    }
+    else {
+      static_dir_ = fs::absolute(fs::current_path().string()).string();
+    }
+
+    files_.clear();
+    for (const auto &file :
+         std::filesystem::recursive_directory_iterator(static_dir_)) {
+      if (!file.is_directory()) {
+        files_.push_back(file.path().string());
+      }
+    }
+
+    std::filesystem::path router_path =
+        std::filesystem::path(static_dir_router_path_);
+
+    std::string uri;
+    for (auto &file : files_) {
+      auto relative_path =
+          std::filesystem::path(file.substr(static_dir_.length())).string();
+      if (size_t pos = relative_path.find('\\') != std::string::npos) {
+        replace_all(relative_path, "\\", "/");
+      }
+      uri = std::string("/")
+                .append(static_dir_router_path_)
+                .append(relative_path);
+
+      set_http_handler<cinatra::GET>(
+          uri,
+          [this, file_name = file](
+              coro_http_request &req,
+              coro_http_response &resp) -> async_simple::coro::Lazy<void> {
+            bool is_chunked = req.is_chunked();
+            bool is_ranges = req.is_ranges();
+            if (!is_chunked && !is_ranges) {
+              resp.set_status(status_type::not_implemented);
+              co_return;
+            }
+
+            std::string_view extension = get_extension(file_name);
+            std::string_view mime = get_mime_type(extension);
+
+            std::string content;
+            detail::resize(content, chunked_size_);
+
+            coro_io::coro_file in_file{};
+            co_await in_file.async_open(file_name, coro_io::flags::read_only);
+            if (!in_file.is_open()) {
+              resp.set_status_and_content(status_type::not_found,
+                                          file_name + "not found");
+              co_return;
+            }
+
+            if (is_chunked) {
+              resp.set_format_type(format_type::chunked);
+              bool ok;
+              if (ok = co_await resp.get_conn()->begin_chunked(); !ok) {
+                co_return;
+              }
+
+              while (true) {
+                auto [ec, size] =
+                    co_await in_file.async_read(content.data(), content.size());
+                if (ec) {
+                  resp.set_status(status_type::no_content);
+                  co_await resp.get_conn()->reply();
+                  co_return;
+                }
+
+                bool r = co_await resp.get_conn()->write_chunked(
+                    std::string_view(content.data(), size));
+                if (!r) {
+                  co_return;
+                }
+
+                if (in_file.eof()) {
+                  co_await resp.get_conn()->end_chunked();
+                  break;
+                }
+              }
+            }
+            else if (is_ranges) {
+              auto range_header = build_range_header(
+                  mime, file_name, coro_io::coro_file::file_size(file_name));
+              resp.set_delay(true);
+              bool r = co_await req.get_conn()->write_data(range_header);
+              if (!r) {
+                co_return;
+              }
+
+              while (true) {
+                auto [ec, size] =
+                    co_await in_file.async_read(content.data(), content.size());
+                if (ec) {
+                  resp.set_status(status_type::no_content);
+                  co_await resp.get_conn()->reply();
+                  co_return;
+                }
+
+                r = co_await req.get_conn()->write_data(
+                    std::string_view(content.data(), size));
+                if (!r) {
+                  co_return;
+                }
+
+                if (in_file.eof()) {
+                  break;
+                }
+              }
+            }
+          });
+    }
+  }
+
   void set_check_duration(auto duration) { check_duration_ = duration; }
 
   void set_timeout_duration(
@@ -305,6 +441,20 @@ class coro_http_server {
     }
   }
 
+  std::string build_range_header(std::string_view mime,
+                                 std::string_view filename, size_t file_size) {
+    std::string header_str =
+        "HTTP/1.1 200 OK\r\nAccess-Control-Allow-origin: "
+        "*\r\nAccept-Ranges: bytes\r\n";
+    header_str.append("Content-Disposition: attachment;filename=");
+    header_str.append(filename).append("\r\n");
+    header_str.append("Connection: keep-alive\r\n");
+    header_str.append("Content-Type: ").append(mime).append("\r\n");
+    header_str.append("Content-Length: ");
+    header_str.append(std::to_string(file_size)).append("\r\n\r\n");
+    return header_str;
+  }
+
  private:
   std::unique_ptr<coro_io::io_context_pool> pool_;
   asio::io_context *out_ctx_ = nullptr;
@@ -325,6 +475,11 @@ class coro_http_server {
   asio::steady_timer check_timer_;
   bool need_check_ = false;
   std::atomic<bool> stop_timer_ = false;
+
+  std::string static_dir_router_path_ = "";
+  std::string static_dir_ = "";
+  std::vector<std::string> files_;
+  size_t chunked_size_ = 1024 * 10;
 #ifdef CINATRA_ENABLE_SSL
   std::string cert_file_;
   std::string key_file_;
diff --git a/include/cinatra/http_parser.hpp b/include/cinatra/http_parser.hpp
index 308d07ca..2935f10e 100644
--- a/include/cinatra/http_parser.hpp
+++ b/include/cinatra/http_parser.hpp
@@ -127,7 +127,7 @@ class http_parser {
   }
 
   bool is_ranges() const {
-    auto transfer_encoding = this->get_header_value("Accept-Ranges"sv);
+    auto transfer_encoding = this->get_header_value("Range"sv);
     return !transfer_encoding.empty();
   }
 
diff --git a/include/cinatra/uri.hpp b/include/cinatra/uri.hpp
index 39750404..40943256 100644
--- a/include/cinatra/uri.hpp
+++ b/include/cinatra/uri.hpp
@@ -308,7 +308,7 @@ struct context {
         port(u.get_port()),
         path(u.get_path()),
         query(u.get_query()),
-        method(mthd),
-        body(std::move(b)) {}
+        body(std::move(b)),
+        method(mthd) {}
 };
 }  // namespace cinatra
\ No newline at end of file
diff --git a/include/cinatra/websocket.hpp b/include/cinatra/websocket.hpp
index 52c9a1e7..bb0509e2 100644
--- a/include/cinatra/websocket.hpp
+++ b/include/cinatra/websocket.hpp
@@ -304,7 +304,6 @@ class websocket {
   std::string_view sec_ws_key_;
 
   size_t payload_length_ = 0;
-  size_t left_payload_length_ = 0;
 
   size_t left_header_len_ = 0;
   uint8_t mask_[4] = {};
diff --git a/tests/test_coro_http_server.cpp b/tests/test_coro_http_server.cpp
index c671e1cf..78029589 100644
--- a/tests/test_coro_http_server.cpp
+++ b/tests/test_coro_http_server.cpp
@@ -766,7 +766,6 @@ TEST_CASE("test websocket with different message sizes") {
         return;
       }
 
-      size_t size = data.resp_body.size();
       std::cout << "ws msg len: " << data.resp_body.size() << std::endl;
       REQUIRE(data.resp_body == medium_message);
     });
@@ -861,7 +860,6 @@ TEST_CASE("test websocket with message max_size limit") {
         return;
       }
 
-      size_t size = data.resp_body.size();
       std::cout << "ws msg len: " << data.resp_body.size() << std::endl;
       REQUIRE(data.resp_body == medium_message);
     });
@@ -922,6 +920,48 @@ TEST_CASE("test ssl server") {
 }
 #endif
 
+TEST_CASE("test http download server") {
+  cinatra::coro_http_server server(1, 9001);
+  std::string filename = "test_download.txt";
+  create_file(filename, 1010);
+
+  // curl http://127.0.0.1:9001/download/test_download.txt will download
+  // test_download.txt file
+  server.set_transfer_chunked_size(100);
+  server.set_static_res_handler("download", "");
+  server.async_start();
+  std::this_thread::sleep_for(200ms);
+
+  {
+    coro_http_client client{};
+    auto result = async_simple::coro::syncAwait(client.async_download(
+        "http://127.0.0.1:9001/download/test_download.txt", "download.txt"));
+
+    CHECK(result.status == 200);
+    std::string download_file = fs::absolute("download.txt").string();
+    std::ifstream ifs(download_file, std::ios::binary);
+    std::string content((std::istreambuf_iterator<char>(ifs)),
+                        (std::istreambuf_iterator<char>()));
+    CHECK(content.size() == 1010);
+    CHECK(content[0] == 'A');
+  }
+
+  {
+    coro_http_client client{};
+    auto result = async_simple::coro::syncAwait(client.async_download(
+        "http://127.0.0.1:9001/download/test_download.txt", "download.txt",
+        "0-"));
+
+    CHECK(result.status == 200);
+    std::string download_file = fs::absolute("download.txt").string();
+    std::ifstream ifs(download_file, std::ios::binary);
+    std::string content((std::istreambuf_iterator<char>(ifs)),
+                        (std::istreambuf_iterator<char>()));
+    CHECK(content.size() == 1010);
+    CHECK(content[0] == 'A');
+  }
+}
+
 DOCTEST_MSVC_SUPPRESS_WARNING_WITH_PUSH(4007)
 int main(int argc, char **argv) { return doctest::Context(argc, argv).run(); }
 DOCTEST_MSVC_SUPPRESS_WARNING_POP
\ No newline at end of file