diff --git a/mio/lib/Makefile.am b/mio/lib/Makefile.am
index 7880016..072544d 100644
--- a/mio/lib/Makefile.am
+++ b/mio/lib/Makefile.am
@@ -58,6 +58,7 @@ libmio_la_SOURCES = \
 	htre.c \
 	http.c \
 	http-cgi.c \
+	http-fil.c \
 	http-svr.c \
 	http-thr.c \
 	http-txt.c \
diff --git a/mio/lib/Makefile.in b/mio/lib/Makefile.in
index c8f2741..6c384b5 100644
--- a/mio/lib/Makefile.in
+++ b/mio/lib/Makefile.in
@@ -145,24 +145,26 @@ libmio_la_DEPENDENCIES = $(am__DEPENDENCIES_2) $(am__DEPENDENCIES_1) \
 	$(am__DEPENDENCIES_1)
 am__libmio_la_SOURCES_DIST = chr.c dns.c dns-cli.c ecs.c ecs-imp.h \
 	err.c fmt.c fmt-imp.h htb.c htrd.c htre.c http.c http-cgi.c \
-	http-svr.c http-thr.c http-txt.c json.c mio-prv.h mio.c nwif.c \
-	path.c pipe.c pro.c sck.c skad.c sys.c sys-ass.c sys-err.c \
-	sys-log.c sys-mux.c sys-prv.h sys-tim.c thr.c uch-case.h \
-	uch-prop.h tmr.c utf8.c utl.c utl-siph.c mar.c mar-cli.c
+	http-fil.c http-svr.c http-thr.c http-txt.c json.c mio-prv.h \
+	mio.c nwif.c path.c pipe.c pro.c sck.c skad.c sys.c sys-ass.c \
+	sys-err.c sys-log.c sys-mux.c sys-prv.h sys-tim.c thr.c \
+	uch-case.h uch-prop.h tmr.c utf8.c utl.c utl-siph.c mar.c \
+	mar-cli.c
 @ENABLE_MARIADB_TRUE@am__objects_1 = libmio_la-mar.lo \
 @ENABLE_MARIADB_TRUE@	libmio_la-mar-cli.lo
 am_libmio_la_OBJECTS = libmio_la-chr.lo libmio_la-dns.lo \
 	libmio_la-dns-cli.lo libmio_la-ecs.lo libmio_la-err.lo \
 	libmio_la-fmt.lo libmio_la-htb.lo libmio_la-htrd.lo \
 	libmio_la-htre.lo libmio_la-http.lo libmio_la-http-cgi.lo \
-	libmio_la-http-svr.lo libmio_la-http-thr.lo \
-	libmio_la-http-txt.lo libmio_la-json.lo libmio_la-mio.lo \
-	libmio_la-nwif.lo libmio_la-path.lo libmio_la-pipe.lo \
-	libmio_la-pro.lo libmio_la-sck.lo libmio_la-skad.lo \
-	libmio_la-sys.lo libmio_la-sys-ass.lo libmio_la-sys-err.lo \
-	libmio_la-sys-log.lo libmio_la-sys-mux.lo libmio_la-sys-tim.lo \
-	libmio_la-thr.lo libmio_la-tmr.lo libmio_la-utf8.lo \
-	libmio_la-utl.lo libmio_la-utl-siph.lo $(am__objects_1)
+	libmio_la-http-fil.lo libmio_la-http-svr.lo \
+	libmio_la-http-thr.lo libmio_la-http-txt.lo libmio_la-json.lo \
+	libmio_la-mio.lo libmio_la-nwif.lo libmio_la-path.lo \
+	libmio_la-pipe.lo libmio_la-pro.lo libmio_la-sck.lo \
+	libmio_la-skad.lo libmio_la-sys.lo libmio_la-sys-ass.lo \
+	libmio_la-sys-err.lo libmio_la-sys-log.lo libmio_la-sys-mux.lo \
+	libmio_la-sys-tim.lo libmio_la-thr.lo libmio_la-tmr.lo \
+	libmio_la-utf8.lo libmio_la-utl.lo libmio_la-utl-siph.lo \
+	$(am__objects_1)
 libmio_la_OBJECTS = $(am_libmio_la_OBJECTS)
 AM_V_lt = $(am__v_lt_@AM_V@)
 am__v_lt_ = $(am__v_lt_@AM_DEFAULT_V@)
@@ -193,6 +195,7 @@ am__depfiles_remade = ./$(DEPDIR)/libmio_la-chr.Plo \
 	./$(DEPDIR)/libmio_la-htb.Plo ./$(DEPDIR)/libmio_la-htrd.Plo \
 	./$(DEPDIR)/libmio_la-htre.Plo \
 	./$(DEPDIR)/libmio_la-http-cgi.Plo \
+	./$(DEPDIR)/libmio_la-http-fil.Plo \
 	./$(DEPDIR)/libmio_la-http-svr.Plo \
 	./$(DEPDIR)/libmio_la-http-thr.Plo \
 	./$(DEPDIR)/libmio_la-http-txt.Plo \
@@ -405,6 +408,7 @@ pdfdir = @pdfdir@
 prefix = @prefix@
 program_transform_name = @program_transform_name@
 psdir = @psdir@
+runstatedir = @runstatedir@
 sbindir = @sbindir@
 sharedstatedir = @sharedstatedir@
 srcdir = @srcdir@
@@ -438,11 +442,11 @@ include_HEADERS = mio-cfg.h mio-chr.h mio-cmn.h mio-dns.h mio-ecs.h \
 	mio.h $(am__append_1)
 lib_LTLIBRARIES = libmio.la
 libmio_la_SOURCES = chr.c dns.c dns-cli.c ecs.c ecs-imp.h err.c fmt.c \
-	fmt-imp.h htb.c htrd.c htre.c http.c http-cgi.c http-svr.c \
-	http-thr.c http-txt.c json.c mio-prv.h mio.c nwif.c path.c \
-	pipe.c pro.c sck.c skad.c sys.c sys-ass.c sys-err.c sys-log.c \
-	sys-mux.c sys-prv.h sys-tim.c thr.c uch-case.h uch-prop.h \
-	tmr.c utf8.c utl.c utl-siph.c $(am__append_2)
+	fmt-imp.h htb.c htrd.c htre.c http.c http-cgi.c http-fil.c \
+	http-svr.c http-thr.c http-txt.c json.c mio-prv.h mio.c nwif.c \
+	path.c pipe.c pro.c sck.c skad.c sys.c sys-ass.c sys-err.c \
+	sys-log.c sys-mux.c sys-prv.h sys-tim.c thr.c uch-case.h \
+	uch-prop.h tmr.c utf8.c utl.c utl-siph.c $(am__append_2)
 libmio_la_CPPFLAGS = $(CPPFLAGS_LIB_COMMON)
 libmio_la_LDFLAGS = $(LDFLAGS_LIB_COMMON) $(am__append_3)
 libmio_la_LIBADD = $(LIBADD_LIB_COMMON) $(SSL_LIBS) $(SOCKET_LIBS) \
@@ -551,6 +555,7 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libmio_la-htrd.Plo@am__quote@ # am--include-marker
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libmio_la-htre.Plo@am__quote@ # am--include-marker
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libmio_la-http-cgi.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libmio_la-http-fil.Plo@am__quote@ # am--include-marker
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libmio_la-http-svr.Plo@am__quote@ # am--include-marker
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libmio_la-http-thr.Plo@am__quote@ # am--include-marker
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libmio_la-http-txt.Plo@am__quote@ # am--include-marker
@@ -684,6 +689,13 @@ libmio_la-http-cgi.lo: http-cgi.c
 @AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
 @am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(libmio_la_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o libmio_la-http-cgi.lo `test -f 'http-cgi.c' || echo '$(srcdir)/'`http-cgi.c
 
+libmio_la-http-fil.lo: http-fil.c
+@am__fastdepCC_TRUE@	$(AM_V_CC)$(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(libmio_la_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT libmio_la-http-fil.lo -MD -MP -MF $(DEPDIR)/libmio_la-http-fil.Tpo -c -o libmio_la-http-fil.lo `test -f 'http-fil.c' || echo '$(srcdir)/'`http-fil.c
+@am__fastdepCC_TRUE@	$(AM_V_at)$(am__mv) $(DEPDIR)/libmio_la-http-fil.Tpo $(DEPDIR)/libmio_la-http-fil.Plo
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	$(AM_V_CC)source='http-fil.c' object='libmio_la-http-fil.lo' libtool=yes @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(libmio_la_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o libmio_la-http-fil.lo `test -f 'http-fil.c' || echo '$(srcdir)/'`http-fil.c
+
 libmio_la-http-svr.lo: http-svr.c
 @am__fastdepCC_TRUE@	$(AM_V_CC)$(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(libmio_la_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT libmio_la-http-svr.lo -MD -MP -MF $(DEPDIR)/libmio_la-http-svr.Tpo -c -o libmio_la-http-svr.lo `test -f 'http-svr.c' || echo '$(srcdir)/'`http-svr.c
 @am__fastdepCC_TRUE@	$(AM_V_at)$(am__mv) $(DEPDIR)/libmio_la-http-svr.Tpo $(DEPDIR)/libmio_la-http-svr.Plo
@@ -1017,6 +1029,7 @@ distclean: distclean-am
 	-rm -f ./$(DEPDIR)/libmio_la-htrd.Plo
 	-rm -f ./$(DEPDIR)/libmio_la-htre.Plo
 	-rm -f ./$(DEPDIR)/libmio_la-http-cgi.Plo
+	-rm -f ./$(DEPDIR)/libmio_la-http-fil.Plo
 	-rm -f ./$(DEPDIR)/libmio_la-http-svr.Plo
 	-rm -f ./$(DEPDIR)/libmio_la-http-thr.Plo
 	-rm -f ./$(DEPDIR)/libmio_la-http-txt.Plo
@@ -1098,6 +1111,7 @@ maintainer-clean: maintainer-clean-am
 	-rm -f ./$(DEPDIR)/libmio_la-htrd.Plo
 	-rm -f ./$(DEPDIR)/libmio_la-htre.Plo
 	-rm -f ./$(DEPDIR)/libmio_la-http-cgi.Plo
+	-rm -f ./$(DEPDIR)/libmio_la-http-fil.Plo
 	-rm -f ./$(DEPDIR)/libmio_la-http-svr.Plo
 	-rm -f ./$(DEPDIR)/libmio_la-http-thr.Plo
 	-rm -f ./$(DEPDIR)/libmio_la-http-txt.Plo
diff --git a/mio/lib/http-cgi.c b/mio/lib/http-cgi.c
index 12489ea..7382a4e 100644
--- a/mio/lib/http-cgi.c
+++ b/mio/lib/http-cgi.c
@@ -111,6 +111,7 @@ static int cgi_state_write_to_client (cgi_state_t* cgi_state, const void* data,
 
 	if (cgi_state->num_pending_writes_to_client > CGI_STATE_PENDING_IO_THRESHOLD)
 	{
+		/* disable reading on the output stream of the peer */
 		if (mio_dev_pro_read(cgi_state->peer, MIO_DEV_PRO_OUT, 0) <= -1) return -1;
 	}
 	return 0;
@@ -242,7 +243,10 @@ printf ("DETACHING FROM THE MAIN CLIENT RSRC... state -> %p\n", cgi_state->clien
 
 static void cgi_state_on_kill (cgi_state_t* cgi_state)
 {
-printf ("**** CGI_STATE_ON_KILL \n");
+	mio_t* mio = cgi_state->htts->mio;
+
+	MIO_DEBUG2 (mio, "HTTS(%p) - killing cgi_state client(%p)\n", cgi_state->htts, cgi_state->client->sck);
+
 	if (cgi_state->peer)
 	{
 		cgi_peer_xtn_t* cgi_peer = mio_dev_pro_getxtn(cgi_state->peer);
@@ -273,7 +277,6 @@ printf ("**** CGI_STATE_ON_KILL \n");
 		cgi_state->client_org_on_write = MIO_NULL;
 	}
 
-
 	if (cgi_state->client_org_on_disconnect)
 	{
 		cgi_state->client->sck->on_disconnect = cgi_state->client_org_on_disconnect;
@@ -288,15 +291,15 @@ printf ("**** CGI_STATE_ON_KILL \n");
 
 	if (!cgi_state->client_disconnected)
 	{
-printf ("ENABLING INPUT WATCHING on CLIENT %p. \n", cgi_state->client->sck);
+/*printf ("ENABLING INPUT WATCHING on CLIENT %p. \n", cgi_state->client->sck);*/
 		if (!cgi_state->keep_alive || mio_dev_sck_read(cgi_state->client->sck, 1) <= -1)
 		{
-			MIO_DEBUG2 (cgi_state->htts->mio, "HTTS(%p) - halting client(%p) for failure to enable input watching\n", cgi_state->htts, cgi_state->client->sck);
+			MIO_DEBUG2 (mio, "HTTS(%p) - halting client(%p) for failure to enable input watching\n", cgi_state->htts, cgi_state->client->sck);
 			mio_dev_sck_halt (cgi_state->client->sck);
 		}
 	}
 
-printf ("**** CGI_STATE_ON_KILL DONE\n");
+/*printf ("**** CGI_STATE_ON_KILL DONE\n");*/
 }
 
 static void cgi_peer_on_close (mio_dev_pro_t* pro, mio_dev_pro_sid_t sid)
diff --git a/mio/lib/http-fil.c b/mio/lib/http-fil.c
new file mode 100644
index 0000000..e08059a
--- /dev/null
+++ b/mio/lib/http-fil.c
@@ -0,0 +1,606 @@
+/*
+ * $Id$
+ *
+    Copyright (c) 2016-2020 Chung, Hyung-Hwan. All rights reserved.
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions
+    are met:
+    1. Redistributions of source code must retain the above copyright
+       notice, this list of conditions and the following disclaimer.
+    2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in the
+       documentation and/or other materials provided with the distribution.
+
+    THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS OR
+    IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WAfRRANTIES
+    OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+    IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+    NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+    THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "http-prv.h"
+#include <mio-pro.h>
+#include <mio-fmt.h>
+#include <mio-chr.h>
+
+#include <unistd.h> /* TODO: move file operations to sys-file.XXX */
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <stdlib.h> /* setenv, clearenv */
+
+#define FILE_ALLOW_UNLIMITED_REQ_CONTENT_LENGTH
+
+enum file_state_res_mode_t
+{
+	FILE_STATE_RES_MODE_CHUNKED,
+	FILE_STATE_RES_MODE_CLOSE,
+	FILE_STATE_RES_MODE_LENGTH
+};
+typedef enum file_state_res_mode_t file_state_res_mode_t;
+
+#define FILE_STATE_PENDING_IO_THRESHOLD 5
+
+#define FILE_STATE_OVER_READ_FROM_CLIENT (1 << 0)
+#define FILE_STATE_OVER_READ_FROM_PEER   (1 << 1)
+#define FILE_STATE_OVER_WRITE_TO_CLIENT  (1 << 2)
+#define FILE_STATE_OVER_WRITE_TO_PEER    (1 << 3)
+#define FILE_STATE_OVER_ALL (FILE_STATE_OVER_READ_FROM_CLIENT | FILE_STATE_OVER_READ_FROM_PEER | FILE_STATE_OVER_WRITE_TO_CLIENT | FILE_STATE_OVER_WRITE_TO_PEER)
+
+struct file_state_t
+{
+	MIO_SVC_HTTS_RSRC_HEADER;
+
+	mio_oow_t num_pending_writes_to_client;
+	mio_oow_t num_pending_writes_to_peer;
+	int peer;
+
+	mio_svc_htts_cli_t* client;
+	mio_http_version_t req_version; /* client request */
+
+	unsigned int over: 4; /* must be large enough to accomodate FILE_STATE_OVER_ALL */
+	unsigned int keep_alive: 1;
+	unsigned int req_content_length_unlimited: 1;
+	unsigned int ever_attempted_to_write_to_client: 1;
+	unsigned int client_disconnected: 1;
+	unsigned int client_htrd_recbs_changed: 1;
+	mio_oow_t req_content_length; /* client request content length */
+	file_state_res_mode_t res_mode_to_cli;
+
+	mio_dev_sck_on_read_t client_org_on_read;
+	mio_dev_sck_on_write_t client_org_on_write;
+	mio_dev_sck_on_disconnect_t client_org_on_disconnect;
+	mio_htrd_recbs_t client_htrd_org_recbs;
+
+};
+typedef struct file_state_t file_state_t;
+
+
+static void file_state_halt_participating_devices (file_state_t* file_state)
+{
+	MIO_ASSERT (file_state->client->htts->mio, file_state->client != MIO_NULL);
+	MIO_ASSERT (file_state->client->htts->mio, file_state->client->sck != MIO_NULL);
+
+	MIO_DEBUG4 (file_state->client->htts->mio, "HTTS(%p) - Halting participating devices in file state %p(client=%p,peer=%d)\n", file_state->client->htts, file_state, file_state->client->sck, (int)file_state->peer);
+
+
+	mio_dev_sck_halt (file_state->client->sck);
+}
+
+static int file_state_write_to_client (file_state_t* file_state, const void* data, mio_iolen_t dlen)
+{
+	file_state->ever_attempted_to_write_to_client = 1;
+
+	file_state->num_pending_writes_to_client++;
+	if (mio_dev_sck_write(file_state->client->sck, data, dlen, MIO_NULL, MIO_NULL) <= -1)  /* TODO: use sendfile here.. */
+	{
+		file_state->num_pending_writes_to_client--;
+		return -1;
+	}
+
+	if (file_state->num_pending_writes_to_client > FILE_STATE_PENDING_IO_THRESHOLD)
+	{
+		/* STOP READING */
+		/*if (mio_dev_pro_read(file_state->peer, MIO_DEV_PRO_OUT, 0) <= -1) return -1;*/
+	}
+	return 0;
+}
+
+
+#if 0
+
+static int file_state_writev_to_client (file_state_t* file_state, mio_iovec_t* iov, mio_iolen_t iovcnt)
+{
+	file_state->ever_attempted_to_write_to_client = 1;
+
+	file_state->num_pending_writes_to_client++;
+	if (mio_dev_sck_writev(file_state->client->sck, iov, iovcnt, MIO_NULL, MIO_NULL) <= -1) 
+	{
+		file_state->num_pending_writes_to_client--;
+		return -1;
+	}
+
+	if (file_state->num_pending_writes_to_client > FILE_STATE_PENDING_IO_THRESHOLD)
+	{
+		if (mio_dev_pro_read(file_state->peer, MIO_DEV_PRO_OUT, 0) <= -1) return -1;
+	}
+	return 0;
+}
+
+#endif
+
+static int file_state_send_final_status_to_client (file_state_t* file_state, int status_code, int force_close)
+{
+	mio_svc_htts_cli_t* cli = file_state->client;
+	mio_bch_t dtbuf[64];
+
+	mio_svc_htts_fmtgmtime (cli->htts, MIO_NULL, dtbuf, MIO_COUNTOF(dtbuf));
+
+	if (!force_close) force_close = !file_state->keep_alive;
+	if (mio_becs_fmt(cli->sbuf, "HTTP/%d.%d %d %hs\r\nServer: %hs\r\nDate: %s\r\nConnection: %hs\r\nContent-Length: 0\r\n\r\n",
+		file_state->req_version.major, file_state->req_version.minor,
+		status_code, mio_http_status_to_bcstr(status_code),
+		cli->htts->server_name, dtbuf,
+		(force_close? "close": "keep-alive")) == (mio_oow_t)-1) return -1;
+
+	return (file_state_write_to_client(file_state, MIO_BECS_PTR(cli->sbuf), MIO_BECS_LEN(cli->sbuf)) <= -1 ||
+	        (force_close && file_state_write_to_client(file_state, MIO_NULL, 0) <= -1))? -1: 0;
+}
+
+
+#if 0
+
+static int file_state_write_last_chunk_to_client (file_state_t* file_state)
+{
+	if (!file_state->ever_attempted_to_write_to_client)
+	{
+		if (file_state_send_final_status_to_client(file_state, 500, 0) <= -1) return -1;
+	}
+	else
+	{
+		if (file_state->res_mode_to_cli == FILE_STATE_RES_MODE_CHUNKED &&
+		    file_state_write_to_client(file_state, "0\r\n\r\n", 5) <= -1) return -1;
+	}
+
+	if (!file_state->keep_alive && file_state_write_to_client(file_state, MIO_NULL, 0) <= -1) return -1;
+	return 0;
+}
+
+static int file_state_write_to_peer (file_state_t* file_state, const void* data, mio_iolen_t dlen)
+{
+	file_state->num_pending_writes_to_peer++;
+	if (mio_dev_pro_write(file_state->peer, data, dlen, MIO_NULL) <= -1) 
+	{
+		file_state->num_pending_writes_to_peer--;
+		return -1;
+	}
+
+/* TODO: check if it's already finished or something.. */
+	if (file_state->num_pending_writes_to_peer > FILE_STATE_PENDING_IO_THRESHOLD)
+	{
+		if (mio_dev_sck_read(file_state->client->sck, 0) <= -1) return -1;
+	}
+	return 0;
+}
+
+static MIO_INLINE void file_state_mark_over (file_state_t* file_state, int over_bits)
+{
+	unsigned int old_over;
+
+	old_over = file_state->over;
+	file_state->over |= over_bits;
+
+	MIO_DEBUG5 (file_state->htts->mio, "HTTS(%p) - client=%p peer=%p new-bits=%x over=%x\n", file_state->htts, file_state->client->sck, file_state->peer, (int)over_bits, (int)file_state->over);
+
+	if (!(old_over & FILE_STATE_OVER_READ_FROM_CLIENT) && (file_state->over & FILE_STATE_OVER_READ_FROM_CLIENT))
+	{
+		if (mio_dev_sck_read(file_state->client->sck, 0) <= -1) 
+		{
+			MIO_DEBUG2 (file_state->htts->mio, "HTTS(%p) - halting client(%p) for failure to disable input watching\n", file_state->htts, file_state->client->sck);
+			mio_dev_sck_halt (file_state->client->sck);
+		}
+	}
+
+	if (!(old_over & FILE_STATE_OVER_READ_FROM_PEER) && (file_state->over & FILE_STATE_OVER_READ_FROM_PEER))
+	{
+		if (file_state->peer && mio_dev_pro_read(file_state->peer, MIO_DEV_PRO_OUT, 0) <= -1) 
+		{
+			MIO_DEBUG2 (file_state->htts->mio, "HTTS(%p) - halting peer(%p) for failure to disable input watching\n", file_state->htts, file_state->peer);
+			mio_dev_pro_halt (file_state->peer);
+		}
+	}
+
+	if (old_over != FILE_STATE_OVER_ALL && file_state->over == FILE_STATE_OVER_ALL)
+	{
+		/* ready to stop */
+		if (file_state->peer) 
+		{
+			MIO_DEBUG2 (file_state->htts->mio, "HTTS(%p) - halting peer(%p) as it is unneeded\n", file_state->htts, file_state->peer);
+			mio_dev_pro_halt (file_state->peer);
+		}
+
+		if (file_state->keep_alive) 
+		{
+			/* how to arrange to delete this file_state object and put the socket back to the normal waiting state??? */
+			MIO_ASSERT (file_state->htts->mio, file_state->client->rsrc == (mio_svc_htts_rsrc_t*)file_state);
+
+printf ("DETACHING FROM THE MAIN CLIENT RSRC... state -> %p\n", file_state->client->rsrc);
+			MIO_SVC_HTTS_RSRC_DETACH (file_state->client->rsrc);
+			/* file_state must not be access from here down as it could have been destroyed */
+		}
+		else
+		{
+			MIO_DEBUG2 (file_state->htts->mio, "HTTS(%p) - halting client(%p) for no keep-alive\n", file_state->htts, file_state->client->sck);
+			mio_dev_sck_shutdown (file_state->client->sck, MIO_DEV_SCK_SHUTDOWN_WRITE);
+			mio_dev_sck_halt (file_state->client->sck);
+		}
+	}
+}
+
+#endif
+
+static void file_state_on_kill (file_state_t* file_state)
+{
+	mio_t* mio = file_state->htts->mio;
+
+	MIO_DEBUG2 (mio, "HTTS(%p) - killing file_state client(%p)\n", file_state->htts, file_state->client->sck);
+
+	if (file_state->peer >= 0)
+	{
+		close (file_state->peer);
+		file_state->peer = -1;
+	}
+
+
+	if (file_state->client_org_on_read)
+	{
+		file_state->client->sck->on_read = file_state->client_org_on_read;
+		file_state->client_org_on_read = MIO_NULL;
+	}
+
+	if (file_state->client_org_on_write)
+	{
+		file_state->client->sck->on_write = file_state->client_org_on_write;
+		file_state->client_org_on_write = MIO_NULL;
+	}
+
+	if (file_state->client_org_on_disconnect)
+	{
+		file_state->client->sck->on_disconnect = file_state->client_org_on_disconnect;
+		file_state->client_org_on_disconnect = MIO_NULL;
+	}
+
+	if (file_state->client_htrd_recbs_changed)
+	{
+		/* restore the callbacks */
+		mio_htrd_setrecbs (file_state->client->htrd, &file_state->client_htrd_org_recbs);
+	}
+
+	if (!file_state->client_disconnected)
+	{
+/*printf ("ENABLING INPUT WATCHING on CLIENT %p. \n", file_state->client->sck);*/
+		if (!file_state->keep_alive || mio_dev_sck_read(file_state->client->sck, 1) <= -1)
+		{
+			MIO_DEBUG2 (mio, "HTTS(%p) - halting client(%p) for failure to enable input watching\n", file_state->htts, file_state->client->sck);
+			mio_dev_sck_halt (file_state->client->sck);
+		}
+	}
+
+/*printf ("**** FILE_STATE_ON_KILL DONE\n");*/
+}
+
+
+static void file_client_on_disconnect (mio_dev_sck_t* sck)
+{
+	mio_svc_htts_cli_t* cli = mio_dev_sck_getxtn(sck);
+	file_state_t* file_state = (file_state_t*)cli->rsrc;
+	file_state->client_disconnected = 1;
+	file_state->client_org_on_disconnect (sck);
+}
+
+static int file_client_on_read (mio_dev_sck_t* sck, const void* buf, mio_iolen_t len, const mio_skad_t* srcaddr)
+{
+	mio_t* mio = sck->mio;
+	mio_svc_htts_cli_t* cli = mio_dev_sck_getxtn(sck);
+	file_state_t* file_state = (file_state_t*)cli->rsrc;
+
+	MIO_ASSERT (mio, sck == cli->sck);
+
+	if (len <= -1)
+	{
+		/* read error */
+		MIO_DEBUG2 (cli->htts->mio, "HTTPS(%p) - read error on client %p(%d)\n", sck, (int)sck->hnd);
+		goto oops;
+	}
+
+#if 0
+XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+	if (!file_state->peer)
+	{
+		/* the peer is gone */
+		goto oops; /* do what?  just return 0? */
+	}
+
+	if (len == 0)
+	{
+		/* EOF on the client side. arrange to close */
+		MIO_DEBUG3 (mio, "HTTPS(%p) - EOF from client %p(hnd=%d)\n", file_state->client->htts, sck, (int)sck->hnd);
+
+		if (!(file_state->over & FILE_STATE_OVER_READ_FROM_CLIENT)) /* if this is true, EOF is received without file_client_htrd_poke() */
+		{
+			if (file_state_write_to_peer(file_state, MIO_NULL, 0) <= -1) goto oops;
+			file_state_mark_over (file_state, FILE_STATE_OVER_READ_FROM_CLIENT);
+		}
+	}
+	else
+	{
+		mio_oow_t rem;
+
+		MIO_ASSERT (mio, !(file_state->over & FILE_STATE_OVER_READ_FROM_CLIENT));
+
+		if (mio_htrd_feed(cli->htrd, buf, len, &rem) <= -1) goto oops;
+
+		if (rem > 0)
+		{
+			/* TODO store this to client buffer. once the current resource is completed, arrange to call on_read() with it */
+printf ("UUUUUUUUUUUUUUUUUUUUUUUUUUGGGGGHHHHHHHHHHHH .......... FILE CLIENT GIVING EXCESSIVE DATA AFTER CONTENTS...\n");
+		}
+	}
+#endif
+
+	return 0;
+
+oops:
+	file_state_halt_participating_devices (file_state);
+	return 0;
+}
+
+static int file_client_on_write (mio_dev_sck_t* sck, mio_iolen_t wrlen, void* wrctx, const mio_skad_t* dstaddr)
+{
+	mio_t* mio = sck->mio;
+	mio_svc_htts_cli_t* cli = mio_dev_sck_getxtn(sck);
+	file_state_t* file_state = (file_state_t*)cli->rsrc;
+
+	if (wrlen <= -1)
+	{
+		MIO_DEBUG3 (mio, "HTTPS(%p) - unable to write to client %p(%d)\n", sck->mio, sck, (int)sck->hnd);
+		goto oops;
+	}
+
+	if (wrlen == 0)
+	{
+		/* if the connect is keep-alive, this part may not be called */
+		file_state->num_pending_writes_to_client--;
+		MIO_ASSERT (mio, file_state->num_pending_writes_to_client == 0);
+		MIO_DEBUG3 (mio, "HTTS(%p) - indicated EOF to client %p(%d)\n", file_state->client->htts, sck, (int)sck->hnd);
+		/* since EOF has been indicated to the client, it must not write to the client any further.
+		 * this also means that i don't need any data from the peer side either.
+		 * i don't need to enable input watching on the peer side */
+#if 0
+XXXXXXX
+		file_state_mark_over (file_state, FILE_STATE_OVER_WRITE_TO_CLIENT);
+#endif
+	}
+	else
+	{
+		MIO_ASSERT (mio, file_state->num_pending_writes_to_client > 0);
+
+#if 0
+XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+		file_state->num_pending_writes_to_client--;
+		if (file_state->peer && file_state->num_pending_writes_to_client == FILE_STATE_PENDING_IO_THRESHOLD)
+		{
+			if (!(file_state->over & FILE_STATE_OVER_READ_FROM_PEER) &&
+			    mio_dev_pro_read(file_state->peer, MIO_DEV_PRO_OUT, 1) <= -1) goto oops;
+		}
+
+		if ((file_state->over & FILE_STATE_OVER_READ_FROM_PEER) && file_state->num_pending_writes_to_client <= 0)
+		{
+			file_state_mark_over (file_state, FILE_STATE_OVER_WRITE_TO_CLIENT);
+		}
+#endif
+	}
+
+	return 0;
+
+oops:
+	file_state_halt_participating_devices (file_state);
+	return 0;
+}
+
+
+#if 0
+int mio_svc_htts_dofile (mio_svc_htts_t* htts, mio_dev_sck_t* csck, mio_htre_t* req, const mio_bch_t* docroot, const mio_bch_t* file)
+{
+	switch (mio_htre_getqmethodtype(req))
+	{
+		case MIO_HTTP_OPTIONS:
+			mio_htre_discardcontent (req);
+			/* TODO: return 200 with Allow: OPTIONS, HEAD, GET, POST, PUT, DELETE... */
+			/* However, if there is access configuration, the item list must reflect it */
+			break;
+
+		case MIO_HTTP_HEAD:
+		case MIO_HTTP_GET:
+		case MIO_HTTP_POST:
+			mio_htre_discardcontent (req);
+			break;
+
+		case MIO_HTTP_PUT:
+			break;
+
+		case MIO_HTTP_DELETE:
+			mio_htre_discardcontent (req);
+			break;
+
+		default:
+			/* method not allowed */
+			mio_htre_discardcontent (req);
+			/* schedule to send 405  */
+			break;
+	}
+
+	return 0;
+}
+#endif
+
+int mio_svc_htts_dofile (mio_svc_htts_t* htts, mio_dev_sck_t* csck, mio_htre_t* req, const mio_bch_t* docroot, const mio_bch_t* file)
+{
+	mio_t* mio = htts->mio;
+	mio_svc_htts_cli_t* cli = mio_dev_sck_getxtn(csck);
+	file_state_t* file_state = MIO_NULL;
+	mio_bch_t* actual_file = MIO_NULL;
+
+	/* ensure that you call this function before any contents is received */
+	MIO_ASSERT (mio, mio_htre_getcontentlen(req) == 0);
+
+	actual_file = mio_svc_htts_dupmergepaths(htts, docroot, file);
+	if (MIO_UNLIKELY(!actual_file)) goto oops;
+
+	file_state = (file_state_t*)mio_svc_htts_rsrc_make(htts, MIO_SIZEOF(*file_state), file_state_on_kill);
+	if (MIO_UNLIKELY(!file_state)) goto oops;
+
+	file_state->client = cli;
+	/*file_state->num_pending_writes_to_client = 0;
+	file_state->num_pending_writes_to_peer = 0;*/
+	file_state->req_version = *mio_htre_getversion(req);
+	file_state->req_content_length_unlimited = mio_htre_getreqcontentlen(req, &file_state->req_content_length);
+
+	file_state->client_org_on_read = csck->on_read;
+	file_state->client_org_on_write = csck->on_write;
+	file_state->client_org_on_disconnect = csck->on_disconnect;
+	csck->on_read = file_client_on_read;
+	csck->on_write = file_client_on_write;
+	csck->on_disconnect = file_client_on_disconnect;
+
+	MIO_ASSERT (mio, cli->rsrc == MIO_NULL);
+	MIO_SVC_HTTS_RSRC_ATTACH (file_state, cli->rsrc);
+
+	if (access(actual_file, R_OK) == -1)
+	{
+		file_state_send_final_status_to_client (file_state, 403, 1); /* 403 Forbidden */
+		goto oops; /* TODO: must not go to oops.  just destroy the file_state and finalize the request .. */
+	}
+
+/* TODO: if method is for download... open it in the read mode. if PUT or POST, open it in RDWR mode? */
+	file_state->peer = open(actual_file, O_RDONLY | O_NONBLOCK);
+	if (MIO_UNLIKELY(file_state->peer <= -1)) goto oops;
+/*
+	file_peer = mio_dev_pro_getxtn(file_state->peer);
+	MIO_SVC_HTTS_RSRC_ATTACH (file_state, file_peer->state);
+*/
+
+
+#if !defined(FILE_ALLOW_UNLIMITED_REQ_CONTENT_LENGTH)
+	if (file_state->req_content_length_unlimited)
+	{
+		/* Transfer-Encoding is chunked. no content-length is known in advance. */
+		
+		/* option 1. buffer contents. if it gets too large, send 413 Request Entity Too Large.
+		 * option 2. send 411 Length Required immediately
+		 * option 3. set Content-Length to -1 and use EOF to indicate the end of content [Non-Standard] */
+
+		if (file_state_send_final_status_to_client(file_state, 411, 1) <= -1) goto oops;
+	}
+#endif
+
+	if (req->flags & MIO_HTRE_ATTR_EXPECT100)
+	{
+/* TODO: check method. if GET, file contents can be transmitted without 100 continue ... */
+		if (mio_comp_http_version_numbers(&req->version, 1, 1) >= 0 && 
+		   (file_state->req_content_length_unlimited || file_state->req_content_length > 0)) 
+		{
+			/* 
+			 * Don't send 100 Continue if http verions is lower than 1.1
+			 * [RFC7231] 
+			 *  A server that receives a 100-continue expectation in an HTTP/1.0
+			 *  request MUST ignore that expectation.
+			 *
+			 * Don't send 100 Continue if expected content lenth is 0. 
+			 * [RFC7231]
+			 *  A server MAY omit sending a 100 (Continue) response if it has
+			 *  already received some or all of the message body for the
+			 *  corresponding request, or if the framing indicates that there is
+			 *  no message body.
+			 */
+			mio_bch_t msgbuf[64];
+			mio_oow_t msglen;
+
+			msglen = mio_fmttobcstr(mio, msgbuf, MIO_COUNTOF(msgbuf), "HTTP/%d.%d 100 Continue\r\n\r\n", file_state->req_version.major, file_state->req_version.minor);
+			if (file_state_write_to_client(file_state, msgbuf, msglen) <= -1) goto oops;
+			file_state->ever_attempted_to_write_to_client = 0; /* reset this as it's polluted for 100 continue */
+		}
+	}
+	else if (req->flags & MIO_HTRE_ATTR_EXPECT)
+	{
+		/* 417 Expectation Failed */
+		file_state_send_final_status_to_client(file_state, 417, 1);
+		goto oops;
+	}
+
+#if defined(FILE_ALLOW_UNLIMITED_REQ_CONTENT_LENGTH)
+	if (file_state->req_content_length_unlimited)
+	{
+		/* change the callbacks to subscribe to contents to be uploaded */
+#if 0
+XXXXXXXXXXXX
+		file_state->client_htrd_org_recbs = *mio_htrd_getrecbs(file_state->client->htrd);
+		file_client_htrd_recbs.peek = file_state->client_htrd_org_recbs.peek;
+		mio_htrd_setrecbs (file_state->client->htrd, &file_client_htrd_recbs);
+		file_state->client_htrd_recbs_changed = 1;
+#endif
+	}
+	else
+	{
+#endif
+		if (file_state->req_content_length > 0)
+		{
+#if 0
+XXXXXXXXXXXX
+			/* change the callbacks to subscribe to contents to be uploaded */
+			file_state->client_htrd_org_recbs = *mio_htrd_getrecbs(file_state->client->htrd);
+			file_client_htrd_recbs.peek = file_state->client_htrd_org_recbs.peek;
+			mio_htrd_setrecbs (file_state->client->htrd, &file_client_htrd_recbs);
+			file_state->client_htrd_recbs_changed = 1;
+#endif
+		}
+		else
+		{
+			/* no content to be uploaded from the client */
+			/* indicate EOF to the peer and disable input wathching from the client */
+			if (file_state_write_to_peer(file_state, MIO_NULL, 0) <= -1) goto oops;
+			file_state_mark_over (file_state, FILE_STATE_OVER_READ_FROM_CLIENT | FILE_STATE_OVER_WRITE_TO_PEER);
+		}
+#if defined(FILE_ALLOW_UNLIMITED_REQ_CONTENT_LENGTH)
+	}
+#endif
+
+	/* this may change later if Content-Length is included in the file output */
+	if (req->flags & MIO_HTRE_ATTR_KEEPALIVE)
+	{
+		file_state->keep_alive = 1;
+		file_state->res_mode_to_cli = FILE_STATE_RES_MODE_CHUNKED; 
+		/* the mode still can get switched to FILE_STATE_RES_MODE_LENGTH if the file file emits Content-Length */
+	}
+	else
+	{
+		file_state->keep_alive = 0;
+		file_state->res_mode_to_cli = FILE_STATE_RES_MODE_CLOSE;
+	}
+
+	/* TODO: store current input watching state and use it when destroying the file_state data */
+	if (mio_dev_sck_read(csck, !(file_state->over & FILE_STATE_OVER_READ_FROM_CLIENT)) <= -1) goto oops;
+	mio_freemem (mio, actual_file);
+	return 0;
+
+oops:
+	MIO_DEBUG2 (mio, "HTTS(%p) - FAILURE in dofile - socket(%p)\n", htts, csck);
+	if (file_state) file_state_halt_participating_devices (file_state);
+	if (actual_file) mio_freemem (mio, actual_file);
+	return -1;
+}
diff --git a/mio/lib/http-svr.c b/mio/lib/http-svr.c
index a04179c..0dac469 100644
--- a/mio/lib/http-svr.c
+++ b/mio/lib/http-svr.c
@@ -427,41 +427,6 @@ static MIO_INLINE void* mio_svc_htts_rsrc_getxtn (mio_svc_htts_rsrc_t* rsrc) { r
 /* ----------------------------------------------------------------- */
 
 
-/* ----------------------------------------------------------------- */
-
-int mio_svc_htts_dofile (mio_svc_htts_t* htts, mio_dev_sck_t* csck, mio_htre_t* req, const mio_bch_t* docroot, const mio_bch_t* file)
-{
-	switch (mio_htre_getqmethodtype(req))
-	{
-		case MIO_HTTP_OPTIONS:
-			mio_htre_discardcontent (req);
-			/* TODO: return 200 with Allow: OPTIONS, HEAD, GET, POST, PUT, DELETE... */
-			/* However, if there is access configuration, the item list must reflect it */
-			break;
-
-		case MIO_HTTP_HEAD:
-		case MIO_HTTP_GET:
-		case MIO_HTTP_POST:
-			mio_htre_discardcontent (req);
-			break;
-
-		case MIO_HTTP_PUT:
-			break;
-
-		case MIO_HTTP_DELETE:
-			mio_htre_discardcontent (req);
-			break;
-
-		default:
-			/* method not allowed */
-			mio_htre_discardcontent (req);
-			/* schedule to send 405  */
-			break;
-	}
-
-	return 0;
-}
-
 /* ----------------------------------------------------------------- */
 
 int mio_svc_htts_doproxy (mio_svc_htts_t* htts, mio_dev_sck_t* csck, mio_htre_t* req, const mio_bch_t* upstream)
diff --git a/mio/lib/http-thr.c b/mio/lib/http-thr.c
index e35d06a..2e8da9a 100644
--- a/mio/lib/http-thr.c
+++ b/mio/lib/http-thr.c
@@ -250,7 +250,10 @@ printf ("DETACHING FROM THE MAIN CLIENT RSRC... state -> %p\n", thr_state->clien
 
 static void thr_state_on_kill (thr_state_t* thr_state)
 {
-printf ("**** THR_STATE_ON_KILL \n");
+	mio_t* mio = thr_state->htts->mio;
+
+	MIO_DEBUG2 (mio, "HTTS(%p) - killing thr_state client(%p)\n", thr_state->htts, thr_state->client->sck);
+
 	if (thr_state->peer)
 	{
 		thr_peer_xtn_t* thr_peer = mio_dev_thr_getxtn(thr_state->peer);
@@ -296,15 +299,15 @@ printf ("**** THR_STATE_ON_KILL \n");
 
 	if (!thr_state->client_disconnected)
 	{
-printf ("ENABLING INPUT WATCHING on CLIENT %p. \n", thr_state->client->sck);
+/*printf ("ENABLING INPUT WATCHING on CLIENT %p. \n", thr_state->client->sck);*/
 		if (!thr_state->keep_alive || mio_dev_sck_read(thr_state->client->sck, 1) <= -1)
 		{
-			MIO_DEBUG2 (thr_state->htts->mio, "HTTS(%p) - halting client(%p) for failure to enable input watching\n", thr_state->htts, thr_state->client->sck);
+			MIO_DEBUG2 (mio, "HTTS(%p) - halting client(%p) for failure to enable input watching\n", thr_state->htts, thr_state->client->sck);
 			mio_dev_sck_halt (thr_state->client->sck);
 		}
 	}
 
-printf ("**** THR_STATE_ON_KILL DONE\n");
+/*printf ("**** THR_STATE_ON_KILL DONE\n");*/
 }
 
 static void thr_peer_on_close (mio_dev_thr_t* thr, mio_dev_thr_sid_t sid)
diff --git a/mio/lib/http-txt.c b/mio/lib/http-txt.c
index 95ff01e..7fd23a9 100644
--- a/mio/lib/http-txt.c
+++ b/mio/lib/http-txt.c
@@ -155,7 +155,10 @@ printf ("DETACHING FROM THE MAIN CLIENT RSRC... state -> %p\n", txt_state->clien
 
 static void txt_state_on_kill (txt_state_t* txt_state)
 {
-printf ("**** TXT_STATE_ON_KILL \n");
+	mio_t* mio = txt_state->htts->mio;
+
+	MIO_DEBUG2 (mio, "HTTS(%p) - killing txt_state client(%p)\n", txt_state->htts, txt_state->client->sck);
+
 	if (txt_state->client_org_on_read)
 	{
 		txt_state->client->sck->on_read = txt_state->client_org_on_read;
@@ -182,15 +185,15 @@ printf ("**** TXT_STATE_ON_KILL \n");
 
 	if (!txt_state->client_disconnected)
 	{
-printf ("ENABLING INPUT WATCHING on CLIENT %p. \n", txt_state->client->sck);
+/*printf ("ENABLING INPUT WATCHING on CLIENT %p. \n", txt_state->client->sck);*/
 		if (!txt_state->keep_alive || mio_dev_sck_read(txt_state->client->sck, 1) <= -1)
 		{
-			MIO_DEBUG2 (txt_state->htts->mio, "HTTS(%p) - halting client(%p) for failure to enable input watching\n", txt_state->htts, txt_state->client->sck);
+			MIO_DEBUG2 (mio, "HTTS(%p) - halting client(%p) for failure to enable input watching\n", txt_state->htts, txt_state->client->sck);
 			mio_dev_sck_halt (txt_state->client->sck);
 		}
 	}
 
-printf ("**** TXT_STATE_ON_KILL DONE\n");
+/*printf ("**** TXT_STATE_ON_KILL DONE\n");*/
 }
 
 static int txt_client_htrd_poke (mio_htrd_t* htrd, mio_htre_t* req)