fix(lints): apply clippy suggestions

src/header.rs

@@ -11,7 +11,7 @@ pub const EXPIRE: &str = "expire";
 
 /// Parses the expiry date from the [`custom HTTP header`](EXPIRE).
 pub fn parse_expiry_date(headers: &HeaderMap) -> Result<Option<u128>, ActixError> {
-    if let Some(expire_time) = headers.get(EXPIRE).map(|v| v.to_str().ok()).flatten() {
+    if let Some(expire_time) = headers.get(EXPIRE).and_then(|v| v.to_str().ok()) {
         let timestamp = util::get_system_time()?;
         let expire_time =
             humantime::parse_duration(expire_time).map_err(error::ErrorInternalServerError)?;
@@ -57,8 +57,7 @@ impl ContentDisposition {
             .parameters
             .iter()
             .find(|param| param.is_filename())
-            .map(|param| param.as_filename())
+            .and_then(|param| param.as_filename())
-            .flatten()
             .filter(|file_name| !file_name.is_empty())
             .ok_or_else(|| error::ErrorBadRequest("file data not present"))
     }

src/mime.rs

@@ -25,8 +25,7 @@ pub fn get_mime_type(
     let path = PathBuf::from(&file_name);
     let mut mime_type = file_extension_to_mime(
         path.extension()
-            .map(|v| v.to_str())
+            .and_then(|v| v.to_str())
-            .flatten()
             .unwrap_or_default(),
     );
     for matcher in mime_matchers {

src/paste.rs

@@ -104,8 +104,7 @@ impl Paste {
         }
         let file_name = match PathBuf::from(file_name)
             .file_name()
-            .map(|v| v.to_str())
+            .and_then(|v| v.to_str())
-            .flatten()
         {
             Some("-") => String::from("stdin"),
             Some(v) => v.to_string(),

src/util.rs

@@ -39,10 +39,8 @@ pub fn glob_match_file(mut path: PathBuf) -> Result<PathBuf, ActixError> {
         let glob_path = glob_path.map_err(error::ErrorInternalServerError)?;
         if let Some(extension) = glob_path
             .extension()
-            .map(|v| v.to_str())
+            .and_then(|v| v.to_str())
-            .flatten()
+            .and_then(|v| v.parse().ok())
-            .map(|v| v.parse().ok())
-            .flatten()
         {
             if get_system_time()? < Duration::from_millis(extension) {
                 path = glob_path;