-unset length date file
-file="$_EXEC/static/$STATIC"
-date="$(stat -c %Y "$file")"
-
-if [ -x "$file" -o \! -r "$file" -o \! -f "$file" ]; then
- printf 'HTTP/1.1 403 Forbidden\n\n'
-elif [ "$date" = "$HTTP_IF_NONE_MATCH" ]; then
- printf 'HTTP/1.1 304 Not Modified\n\n'
+unset length date file suffix
+file="$1"
+date="$(stat -Lc %Y "$file")"
+
+# allow overriding magic file recognition
+# don't use this if `file` returns type correctly
+declare -A suffix
+suffix[css]="text/css"
+
+[ -n "$HTTP_IF_MODIFIED_SINCE" ] && cachedate="$(date -d "$HTTP_IF_MODIFIED_SINCE" +%s)"
+
+if printf '%s' "${HTTP_RANGE}" |grep -qE '^bytes=[0-9]+-[0-9]*\r?$'; then
+ _range="${HTTP_RANGE#bytes=}"
+ _bstart="${_range%-*}"
+ _bend="${_range#*-}"
+fi
+
+if ! [ -f "$file" ] || [ -x "$file" ] || ! grep -qm1 '' "$file" ; then
+ printf 'Status:403 Forbidden\r\n\r\n'
+elif [ "$date" = "$cachedate" ]; then
+ printf 'Status:304 Not Modified\r\n'
+ printf 'Last-Modified: %s\r\n\r\n' "$(date -Rd "@$date")"
+elif [ "$_bstart" -gt 0 ] ; then
+ length="$(stat -Lc %s "$file")"
+ magic="${suffix[${file##*.}]:-$(file -bi "$file")}"
+
+ printf 'Status:206 Partial Content\r\n'
+ printf 'Last-Modified: %s\r\n' "$(date -Rd "@$date")"
+ printf 'Content-Type: %s\r\n' "${magic:-all/all}"
+ printf 'Content-Range: bytes %i-%i/%i\r\n' $_bstart $(($length - 1)) $length |debug
+ printf 'Content-Length: %i\r\n' $(($length - $_bstart))
+ printf '\r\n'
+
+ tail -c+"$(($_bstart + 1))" "$file"