diff --git a/include/ylt/coro_io/coro_file.hpp b/include/ylt/coro_io/coro_file.hpp
index a45633b67..bddf79063 100644
--- a/include/ylt/coro_io/coro_file.hpp
+++ b/include/ylt/coro_io/coro_file.hpp
@@ -332,11 +332,11 @@ class coro_file {
         return "rb";
       case flags::create_write:
       case flags::write_only:
-        return "w";
+        return "wb+";
       case flags::read_write:
         return "rb+";
       case flags::append:
-        return "a";
+        return "ab+";
       case flags::create_read_write_append:
         return "ab+";
       case flags::truncate:
diff --git a/include/ylt/thirdparty/cinatra/coro_http_client.hpp b/include/ylt/thirdparty/cinatra/coro_http_client.hpp
index b250c24dc..0d6af95f8 100644
--- a/include/ylt/thirdparty/cinatra/coro_http_client.hpp
+++ b/include/ylt/thirdparty/cinatra/coro_http_client.hpp
@@ -1630,11 +1630,16 @@ class coro_http_client : public std::enable_shared_from_this<coro_http_client> {
     std::string short_name =
         std::filesystem::path(part.filename).filename().string();
     if (is_file) {
-      part_content_head.append("; filename=\"").append(short_name).append("\"");
+      part_content_head.append("; filename=\"")
+          .append(short_name)
+          .append("\"")
+          .append(CRCF);
       auto ext = std::filesystem::path(short_name).extension().string();
       if (auto it = g_content_type_map.find(ext);
           it != g_content_type_map.end()) {
-        part_content_head.append("Content-Type: ").append(it->second);
+        part_content_head.append("Content-Type: ")
+            .append(it->second)
+            .append(CRCF);
       }
 
       std::error_code ec;
@@ -1642,8 +1647,11 @@ class coro_http_client : public std::enable_shared_from_this<coro_http_client> {
         co_return resp_data{
             std::make_error_code(std::errc::no_such_file_or_directory), 404};
       }
+      part_content_head.append(CRCF);
+    }
+    else {
+      part_content_head.append(TWO_CRCF);
     }
-    part_content_head.append(TWO_CRCF);
     if (auto [ec, size] = co_await async_write(asio::buffer(part_content_head));
         ec) {
       co_return resp_data{ec, 404};
@@ -1655,7 +1663,7 @@ class coro_http_client : public std::enable_shared_from_this<coro_http_client> {
       assert(file.is_open());
       std::string file_data;
       detail::resize(file_data, max_single_part_size_);
-      while (!file.eof()) {
+      while (true) {
         auto [rd_ec, rd_size] =
             co_await file.async_read(file_data.data(), file_data.size());
         if (auto [ec, size] =
@@ -1663,19 +1671,22 @@ class coro_http_client : public std::enable_shared_from_this<coro_http_client> {
             ec) {
           co_return resp_data{ec, 404};
         }
+        if (file.eof()) {
+          if (auto [ec, size] = co_await async_write(asio::buffer(CRCF)); ec) {
+            co_return resp_data{ec, 404};
+          }
+          break;
+        }
       }
     }
     else {
-      if (auto [ec, size] = co_await async_write(asio::buffer(part.content));
-          ec) {
+      std::array<asio::const_buffer, 2> arr{asio::buffer(part.content),
+                                            asio::buffer(CRCF)};
+      if (auto [ec, size] = co_await async_write(arr); ec) {
         co_return resp_data{ec, 404};
       }
     }
 
-    if (auto [ec, size] = co_await async_write(asio::buffer(CRCF)); ec) {
-      co_return resp_data{ec, 404};
-    }
-
     co_return resp_data{{}, 200};
   }
 
diff --git a/include/ylt/thirdparty/cinatra/coro_http_connection.hpp b/include/ylt/thirdparty/cinatra/coro_http_connection.hpp
index b1b36180d..e293ad057 100644
--- a/include/ylt/thirdparty/cinatra/coro_http_connection.hpp
+++ b/include/ylt/thirdparty/cinatra/coro_http_connection.hpp
@@ -18,6 +18,7 @@
 #include "sha1.hpp"
 #include "string_resize.hpp"
 #include "websocket.hpp"
+#include "ylt/coro_io/coro_file.hpp"
 #include "ylt/coro_io/coro_io.hpp"
 
 namespace cinatra {
@@ -27,6 +28,12 @@ struct chunked_result {
   std::string_view data;
 };
 
+struct part_head_t {
+  std::error_code ec;
+  std::string name;
+  std::string filename;
+};
+
 struct websocket_result {
   std::error_code ec;
   ws_frame_type type;
@@ -38,9 +45,11 @@ class coro_http_connection
     : public std::enable_shared_from_this<coro_http_connection> {
  public:
   template <typename executor_t>
-  coro_http_connection(executor_t *executor, asio::ip::tcp::socket socket)
+  coro_http_connection(executor_t *executor, asio::ip::tcp::socket socket,
+                       coro_http_router &router)
       : executor_(executor),
         socket_(std::move(socket)),
+        router_(router),
         request_(parser_, this),
         response_(this) {
     buffers_.reserve(3);
@@ -125,9 +134,9 @@ class coro_http_connection
       head_buf_.consume(size);
       keep_alive_ = check_keep_alive();
 
-      bool is_chunked = parser_.is_chunked();
+      auto type = request_.get_content_type();
 
-      if (!is_chunked) {
+      if (type != content_type::chunked && type != content_type::multipart) {
         size_t body_len = parser_.body_len();
         if (body_len == 0) {
           if (parser_.method() == "GET"sv) {
@@ -178,13 +187,12 @@ class coro_http_connection
         request_.set_body(body_);
       }
 
-      auto &router = coro_http_router::instance();
-      if (auto handler = router.get_handler(key); handler) {
-        router.route(handler, request_, response_);
+      if (auto handler = router_.get_handler(key); handler) {
+        router_.route(handler, request_, response_);
       }
       else {
-        if (auto coro_handler = router.get_coro_handler(key); coro_handler) {
-          co_await router.route_coro(coro_handler, request_, response_);
+        if (auto coro_handler = router_.get_coro_handler(key); coro_handler) {
+          co_await router_.route_coro(coro_handler, request_, response_);
         }
         else {
           // not found
@@ -339,6 +347,99 @@ class coro_http_connection
     co_return result;
   }
 
+  async_simple::coro::Lazy<part_head_t> read_part_head() {
+    if (head_buf_.size() > 0) {
+      const char *data_ptr = asio::buffer_cast<const char *>(head_buf_.data());
+      chunked_buf_.sputn(data_ptr, head_buf_.size());
+      head_buf_.consume(head_buf_.size());
+    }
+
+    part_head_t result{};
+    std::error_code ec{};
+    size_t last_size = chunked_buf_.size();
+    size_t size;
+
+    auto get_part_name = [](std::string_view data, std::string_view name,
+                            size_t start) {
+      start += name.length();
+      size_t end = data.find("\"", start);
+      return data.substr(start, end - start);
+    };
+
+    constexpr std::string_view name = "name=\"";
+    constexpr std::string_view filename = "filename=\"";
+
+    while (true) {
+      if (std::tie(ec, size) = co_await async_read_until(chunked_buf_, CRCF);
+          ec) {
+        result.ec = ec;
+        close();
+        co_return result;
+      }
+
+      const char *data_ptr =
+          asio::buffer_cast<const char *>(chunked_buf_.data());
+      chunked_buf_.consume(size);
+      if (*data_ptr == '-') {
+        continue;
+      }
+      std::string_view data{data_ptr, size};
+      if (size == 2) {  // got the head end: \r\n\r\n
+        break;
+      }
+
+      if (size_t pos = data.find("name"); pos != std::string_view::npos) {
+        result.name = get_part_name(data, name, pos);
+
+        if (size_t pos = data.find("filename"); pos != std::string_view::npos) {
+          result.filename = get_part_name(data, filename, pos);
+        }
+        continue;
+      }
+    }
+
+    co_return result;
+  }
+
+  async_simple::coro::Lazy<chunked_result> read_part_body(
+      std::string_view boundary) {
+    chunked_result result{};
+    std::error_code ec{};
+    size_t size = 0;
+
+    if (std::tie(ec, size) = co_await async_read_until(chunked_buf_, boundary);
+        ec) {
+      result.ec = ec;
+      close();
+      co_return result;
+    }
+
+    const char *data_ptr = asio::buffer_cast<const char *>(chunked_buf_.data());
+    chunked_buf_.consume(size);
+    result.data = std::string_view{
+        data_ptr, size - boundary.size() - 4};  //-- boundary \r\n
+
+    if (std::tie(ec, size) = co_await async_read_until(chunked_buf_, CRCF);
+        ec) {
+      result = {};
+      result.ec = ec;
+      close();
+      co_return result;
+    }
+
+    data_ptr = asio::buffer_cast<const char *>(chunked_buf_.data());
+    std::string data{data_ptr, size};
+    if (size > 2) {
+      constexpr std::string_view complete_flag = "--\r\n";
+      if (data == complete_flag) {
+        result.eof = true;
+      }
+    }
+
+    chunked_buf_.consume(size);
+    co_return result;
+  }
+
   async_simple::coro::Lazy<std::error_code> write_websocket(
       std::string_view msg, opcode op = opcode::text) {
     auto header = ws_.format_header(msg.length(), op);
@@ -584,6 +685,7 @@ class coro_http_connection
  private:
   async_simple::Executor *executor_;
   asio::ip::tcp::socket socket_;
+  coro_http_router &router_;
   asio::streambuf head_buf_;
   std::string body_;
   asio::streambuf chunked_buf_;
diff --git a/include/ylt/thirdparty/cinatra/coro_http_request.hpp b/include/ylt/thirdparty/cinatra/coro_http_request.hpp
index 112a41121..07211d955 100644
--- a/include/ylt/thirdparty/cinatra/coro_http_request.hpp
+++ b/include/ylt/thirdparty/cinatra/coro_http_request.hpp
@@ -49,21 +49,13 @@ class coro_http_request {
 
   std::string_view get_body() const { return body_; }
 
-  bool is_chunked() {
-    static bool thread_local is_chunk = parser_.is_chunked();
-    return is_chunk;
-  }
+  bool is_chunked() { return parser_.is_chunked(); }
 
   bool is_resp_ranges() { return parser_.is_resp_ranges(); }
 
   bool is_req_ranges() { return parser_.is_req_ranges(); }
 
   content_type get_content_type() {
-    static content_type thread_local content_type = get_content_type_impl();
-    return content_type;
-  }
-
-  content_type get_content_type_impl() {
     if (is_chunked())
       return content_type::chunked;
 
@@ -93,6 +85,14 @@ class coro_http_request {
     return content_type::unknown;
   }
 
+  std::string_view get_boundary() {
+    auto content_type = get_header_value("content-type");
+    if (content_type.empty()) {
+      return {};
+    }
+    return content_type.substr(content_type.rfind("=") + 1);
+  }
+
   coro_http_connection* get_conn() { return conn_; }
 
   bool is_upgrade() {
diff --git a/include/ylt/thirdparty/cinatra/coro_http_router.hpp b/include/ylt/thirdparty/cinatra/coro_http_router.hpp
index 18946143d..e269a23c0 100644
--- a/include/ylt/thirdparty/cinatra/coro_http_router.hpp
+++ b/include/ylt/thirdparty/cinatra/coro_http_router.hpp
@@ -28,11 +28,6 @@ constexpr inline bool is_lazy_v =
 
 class coro_http_router {
  public:
-  static coro_http_router& instance() {
-    static coro_http_router instance;
-    return instance;
-  }
-
   // eg: "GET hello/" as a key
   template <http_method method, typename Func>
   void set_http_handler(std::string key, Func handler) {
@@ -110,7 +105,6 @@ class coro_http_router {
   const auto& get_coro_handlers() const { return coro_handles_; }
 
  private:
-  coro_http_router() = default;
   std::set<std::string> keys_;
   std::unordered_map<
       std::string_view,
diff --git a/include/ylt/thirdparty/cinatra/coro_http_server.hpp b/include/ylt/thirdparty/cinatra/coro_http_server.hpp
index 6f402fde4..5b4653ff2 100644
--- a/include/ylt/thirdparty/cinatra/coro_http_server.hpp
+++ b/include/ylt/thirdparty/cinatra/coro_http_server.hpp
@@ -128,13 +128,11 @@ class coro_http_server {
   void set_http_handler(std::string key, Func handler) {
     static_assert(sizeof...(method) >= 1, "must set http_method");
     if constexpr (sizeof...(method) == 1) {
-      (coro_http_router::instance().set_http_handler<method>(
-           std::move(key), std::move(handler)),
+      (router_.set_http_handler<method>(std::move(key), std::move(handler)),
        ...);
     }
     else {
-      (coro_http_router::instance().set_http_handler<method>(key, handler),
-       ...);
+      (router_.set_http_handler<method>(key, handler), ...);
     }
   }
 
@@ -181,6 +179,8 @@ class coro_http_server {
     }
   }
 
+  const coro_http_router &get_router() const { return router_; }
+
   void set_file_resp_format_type(file_resp_format_type type) {
     format_type_ = type;
   }
@@ -227,6 +227,7 @@ class coro_http_server {
       if (size_t pos = relative_path.find('\\') != std::string::npos) {
         replace_all(relative_path, "\\", "/");
       }
+
       if (static_dir_router_path_.empty()) {
         uri = relative_path;
       }
@@ -405,8 +406,8 @@ class coro_http_server {
 
       uint64_t conn_id = ++conn_id_;
       CINATRA_LOG_DEBUG << "new connection comming, id: " << conn_id;
-      auto conn =
-          std::make_shared<coro_http_connection>(executor, std::move(socket));
+      auto conn = std::make_shared<coro_http_connection>(
+          executor, std::move(socket), router_);
       if (no_delay_) {
         conn->tcp_socket().set_option(asio::ip::tcp::no_delay(true));
       }
@@ -532,5 +533,6 @@ class coro_http_server {
   std::string passwd_;
   bool use_ssl_ = false;
 #endif
+  coro_http_router router_;
 };
 }  // namespace cinatra
\ No newline at end of file