add some comments and check if tmp/ exists and create it if not

counter.numb

@@ -0,0 +1 @@
+0

src/main.rs

@@ -1,5 +1,11 @@
+// hit-counter-rs
+// it's a hit counter, but in rust.  I am also very new to rust, ごめん
+//
 // Due to the slowness of imagemagick (and calling system commands and w/e else) 
 // the image that the user will see on the page will be -1 behind the actual count
+//
+// todo:
+// all files are relative to working directory -> specifiy via cli and/or some config file
 use actix_web::{
     get,
     App,
@@ -19,6 +25,7 @@ const MONTAGE_PATH: &str = "/bin/montage";
 //const MONTAGE_ARGS: &str = "-tile 6x1 -geometry +0+0 -background none -scale 50";
 const ASSET_DIR: &str = "asset/";
 const TMP_OUTPUT: &str = "tmp/counter.png";
+const TMP_DIR:    &str = "tmp";
 
 
 const BIND_IP: &str = "127.0.0.1";
@@ -104,6 +111,9 @@ async fn main() -> std::io::Result<()> {
     unsafe {
         read_counter();
     }
+    if !std::path::Path::new(TMP_DIR).exists() {
+        std::fs::create_dir(TMP_DIR)?;
+    }
 
     log::info!("starting HTTP server at http://{BIND_IP}:{BIND_PORT}");