re-download improve

.gitignore

@@ -1,2 +1,3 @@
 /target
-.env
+.env
+result

src/migrate.rs

@@ -64,7 +64,7 @@ impl Migrator {
         let name = demo.url.rsplit('/').next().unwrap();
 
         let stored_hash = self.store.hash(name)?;
-        if stored_hash != demo.hash {
+        if stored_hash != Some(demo.hash) {
             warn!(
                 stored_hash = debug(stored_hash),
                 expected_hash = debug(demo.hash),
@@ -81,7 +81,7 @@ impl Migrator {
                 &self.backend,
                 self.store.generate_path(name).to_str().unwrap(),
                 &self.store.generate_url(name),
-                stored_hash,
+                demo.hash,
                 &self.key,
             )
             .await?;

src/store.rs

@@ -31,11 +31,19 @@ impl Store {
     }
 
     pub fn remove(&self, name: &str) -> std::io::Result<()> {
-        fs::remove_file(self.generate_path(name))
+        let path = self.generate_path(name);
+        if path.exists() {
+            fs::remove_file(path)
+        } else {
+            Ok(())
+        }
     }
 
-    pub fn hash(&self, name: &str) -> Result<[u8; 16], Error> {
+    pub fn hash(&self, name: &str) -> Result<Option<[u8; 16]>, Error> {
         let path = self.generate_path(name);
+        if !path.exists() {
+            return Ok(None);
+        }
         let mut file = File::open(path)?;
 
         let mut hash = Context::new();
@@ -53,7 +61,7 @@ impl Store {
             hash.consume(data);
         }
 
-        Ok(hash.compute().0)
+        Ok(Some(hash.compute().0))
     }
 
     pub fn generate_path(&self, name: &str) -> PathBuf {