diff --git a/src/config.rs b/src/config.rs
index 24c3b47..394b38a 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -16,7 +16,17 @@ pub enum AcmeAlgo {
     Rsa(u32),
 }
 
+impl Default for AcmeAlgo {
+    fn default() -> Self {
+        Self::Ec384
+    }
+}
+
 impl AcmeAlgo {
+    pub fn parse_or_default(s: &str) -> AcmeAlgo {
+        Self::parse(s).unwrap_or_else(|_| Default::default())
+    }
+
     pub fn parse(s: &str) -> XResult<AcmeAlgo> {
         match s {
             "ec256" => Ok(AcmeAlgo::Ec256),
@@ -35,7 +45,17 @@ pub enum AcmeMode {
     Test,
 }
 
+impl Default for AcmeMode {
+    fn default() -> Self {
+        Self::Prod
+    }
+}
+
 impl AcmeMode {
+    pub fn parse_or_default(s: &str) -> AcmeMode {
+        Self::parse(s).unwrap_or_else(|_| Default::default())
+    }
+
     pub fn parse(s: &str) -> XResult<AcmeMode> {
         match s {
             "prod" => Ok(AcmeMode::Prod),
diff --git a/src/main.rs b/src/main.rs
index d017e72..1ba68a2 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -16,6 +16,8 @@ use std::collections::BTreeMap;
 use tide::Request;
 use std::process::exit;
 use std::time::Duration;
+use async_std::task;
+use async_std::channel;
 use async_std::channel::Sender;
 use config::AcmeAlgo;
 use config::AcmeMode;
@@ -29,7 +31,7 @@ lazy_static! {
     static ref TOKEN_MAP: RwLock<BTreeMap<String, String>> = RwLock::new(BTreeMap::new());
 }
 
-#[derive(Debug)]
+#[derive(Debug, Default)]
 struct AcmeRequest<'a> {
     contract_email: &'a str,
     primary_name: &'a str,
@@ -38,6 +40,8 @@ struct AcmeRequest<'a> {
     mode: AcmeMode,
     dir: &'a str,
     timeout: u64,
+    key_file: Option<String>,
+    cert_file: Option<String>,
 }
 
 #[async_std::main]
@@ -121,10 +125,10 @@ async fn main() -> tide::Result<()> {
         exit(1);
     });
 
-    let (s, r) = async_std::channel::bounded(1);
+    let (s, r) = channel::bounded(1);
     startup_http_server(s, port);
     r.recv().await.ok();
-    async_std::task::sleep(Duration::from_millis(500)).await;
+    task::sleep(Duration::from_millis(500)).await;
 
     let domains: Vec<&str> = domains_val.collect::<Vec<_>>();
     let primary_name = domains[0];
@@ -138,6 +142,7 @@ async fn main() -> tide::Result<()> {
         mode,
         dir,
         timeout,
+        ..Default::default()
     };
     if let Err(e) = request_domains(acme_request) {
         failure!("Request certificate by acme failed: {}", e);
@@ -199,7 +204,7 @@ fn request_domains(acme_request: AcmeRequest) -> XResult<()> {
 }
 
 fn startup_http_server(s: Sender<i32>, port: u16) {
-    async_std::task::spawn(async move {
+    task::spawn(async move {
         information!("Listen at 0.0.0.0:{}", port);
         let mut app = tide::new();
         app.at("/.well-known/acme-challenge/:token").get(|req: Request<()>| async move {