separate image combine logic

scripts/check_file.lua

@@ -0,0 +1,16 @@
+package.path = package.path .. ';<SCRIPT_PATH>/?.lua';
+
+-- https://stackoverflow.com/questions/4990990/check-if-a-file-exists-with-lua
+local function file_exists(name)
+   local f = io.open(name,"r")
+   if f~=nil then io.close(f) return true else return false end
+end
+
+
+local file_to_check = string.match(ngx.var.request_uri, ".*/(.*)")
+local file_dir = ngx.var.tmp_file_dir
+
+local fullpath = file_dir .. "/" .. file_to_check .. ".jpeg";
+
+ngx.say(file_exists(fullpath))
+