Where is the "file manager"? Can you help me!!!

Dear, I use web server to send "*.bin" file, and use "post handler" to receive data. ... $.ajax({\ url: '/echo', type: 'POST', data: data ... httpd_uri_t echo = { .uri = "/echo", .method = HTTP_POST, .handler = echo_post_handler, .user_ctx = NULL }; The app runs well when the size of bin file lower ...