Handle invalid Client ID/Secret

src/config.rs

@@ -1,5 +1,5 @@
 use super::banner::BANNER;
-use anyhow::{anyhow, Result};
+use anyhow::{anyhow, Error, Result};
 use serde::{Deserialize, Serialize};
 use std::{
   fs,
@@ -127,23 +127,17 @@ impl ClientConfig {
         number += 1;
       }
 
-      // TODO: Handle empty input?
-      let mut client_id = String::new();
-      println!("\nEnter your Client ID: ");
-      stdin().read_line(&mut client_id)?;
-
-      let mut client_secret = String::new();
-      println!("\nEnter your Client Secret: ");
-      stdin().read_line(&mut client_secret)?;
+      let client_id = ClientConfig::get_client_key_from_input("Client ID")?;
+      let client_secret = ClientConfig::get_client_key_from_input("Client Secret")?;
 
       let mut port = String::new();
       println!("\nEnter port of redirect uri (default {}): ", DEFAULT_PORT);
       stdin().read_line(&mut port)?;
       let port = port.trim().parse::<u16>().unwrap_or(DEFAULT_PORT);
 
       let config_yml = ClientConfig {
-        client_id: client_id.trim().to_string(),
-        client_secret: client_secret.trim().to_string(),
+        client_id,
+        client_secret,
         device_id: None,
         port: Some(port),
       };
@@ -161,4 +155,46 @@ impl ClientConfig {
       Ok(())
     }
   }
+
+  fn get_client_key_from_input(type_label: &'static str) -> Result<String> {
+    let mut client_key = String::new();
+    const MAX_RETRIES: u8 = 5;
+    let mut num_retries = 0;
+    loop {
+      println!("\nEnter your {}: ", type_label);
+      stdin().read_line(&mut client_key)?;
+      client_key = client_key.trim().to_string();
+      match ClientConfig::validate_client_key(&client_key) {
+        Ok(_) => return Ok(client_key),
+        Err(error_string) => {
+          println!("{}", error_string);
+          client_key.clear();
+          num_retries += 1;
+          if num_retries == MAX_RETRIES {
+            return Err(Error::from(std::io::Error::new(
+              std::io::ErrorKind::Other,
+              format!("Maximum retries ({}) exceeded.", MAX_RETRIES),
+            )));
+          }
+        }
+      };
+    }
+  }
+
+  fn validate_client_key(key: &str) -> Result<()> {
+    const EXPECTED_LEN: usize = 32;
+    if key.len() != EXPECTED_LEN {
+      Err(Error::from(std::io::Error::new(
+        std::io::ErrorKind::InvalidInput,
+        format!("invalid length: {} (must be {})", key.len(), EXPECTED_LEN,),
+      )))
+    } else if !key.chars().all(|c| c.is_digit(16)) {
+      Err(Error::from(std::io::Error::new(
+        std::io::ErrorKind::InvalidInput,
+        "invalid character found (must be hex digits)",
+      )))
+    } else {
+      Ok(())
+    }
+  }
 }