Boost.Asio文件上传标题

Question

这是我在发布文本数据时使用的内容（即name = Boxxy＆amp; age = 18）

            ostream request_stream(&request);
            request_stream << "POST " << path << " HTTP/1.0\r\n";
            request_stream << "Host: " << host << "\r\n";
            request_stream << "User-Agent: HTTPTool/1.0\r\n";
            request_stream << "Content-Type: application/x-www-form-urlencoded\r\n";
            request_stream << "Content-Length: " << data.length() << "\r\n";
            request_stream << "Accept: */*\r\n";
            request_stream << "Connection: close\r\n\r\n";
            request_stream << data;

而且，在发布文件时，我试图使用它：

            ifstream fin(file.c_str(), ios::binary);
            ostringstream buffer;
            buffer << fin.rdbuf();
            string ctn(buffer.str());
            boost::asio::streambuf request;
            std::ostream request_stream(&request);
            request_stream << "POST " << path << " HTTP/1.0\r\n";
            request_stream << "Host: " << host << "\r\n";
            request_stream << "User-Agent: HTTPTool/1.0\r\n";
            request_stream << "Content-Type: image/png\r\n";
            request_stream << "Content-Disposition: attachment;name=file;filename=a.png\r\n";
            request_stream << "Content-Length: " << ctn.length() << "\r\n";
            request_stream << "Accept: */*\r\n";
            request_stream << "Connection: close\r\n\r\n";
            request_stream << ctn;

此代码返回1，但PHP端没有任何反应。我也尝试使用PUT而不是POST。和不同的内容类型。我的标题有问题，还是我应该做一些与普通POST请求不同的事情？