Refactor constructors of CasperSigner and CasperPrivateKey.

1. Removed duplicated code (from_key_pathbuf()).
2. Handling paths via `AsRef<Path>`.
3. Expose Caspers's `ErrorExt` error.

kairos-cli/bin/commands/deposit.rs

@@ -14,7 +14,7 @@ pub struct Args {
 
 pub fn run(args: Args) -> Result<String, CliError> {
     let _amount: u64 = args.amount.field;
-    let _signer = CasperSigner::from_key_pathbuf(args.private_key_path.field)?;
+    let _signer = CasperSigner::from_file(args.private_key_path.field)?;
 
     // TODO: Create transaction and sign it with `signer`.
 

kairos-cli/bin/commands/transfer.rs

@@ -19,7 +19,7 @@ pub struct Args {
 pub fn run(args: Args) -> Result<String, CliError> {
     let _recipient = CasperPublicKey::from_bytes(args.recipient.as_ref())?;
     let _amount: u64 = args.amount.field;
-    let _signer = CasperSigner::from_key_pathbuf(args.private_key_path.field)?;
+    let _signer = CasperSigner::from_file(args.private_key_path.field)?;
 
     // TODO: Create transaction and sign it with `signer`.
 

kairos-cli/bin/commands/withdraw.rs

@@ -14,7 +14,7 @@ pub struct Args {
 
 pub fn run(args: Args) -> Result<String, CliError> {
     let _amount: u64 = args.amount.field;
-    let _signer = CasperSigner::from_key_pathbuf(args.private_key_path.field)?;
+    let _signer = CasperSigner::from_file(args.private_key_path.field)?;
 
     // TODO: Create transaction and sign it with `signer`.
 

kairos-cli/bin/crypto/error.rs

@@ -1,13 +1,14 @@
+use casper_types::ErrorExt;
 use thiserror::Error;
 
 #[derive(Error, Debug)]
 pub enum CryptoError {
-    /// Unable to load a file from the given path.
-    #[error("failed to load key from file")]
-    KeyLoad,
     /// Failed to parse a public key from a raw data.
-    #[error("failed to parse private key")]
-    FailedToParseKey,
+    #[error("failed to parse private key: {error}")]
+    FailedToParseKey {
+        #[from]
+        error: ErrorExt,
+    },
     /// Invalid public key (hexdigest) or other encoding related error.
     #[error("failed to serialize/deserialize '{context}'")]
     Serialization { context: &'static str },

kairos-cli/bin/crypto/private_key.rs

@@ -1,14 +1,13 @@
-use casper_types::file_utils::read_file;
+use std::path::Path;
 
-use crate::crypto::error::CryptoError;
+use super::error::CryptoError;
 
 pub struct CasperPrivateKey(pub casper_types::SecretKey);
 
 impl CasperPrivateKey {
-    pub fn from_file(file_path: &str) -> Result<Self, CryptoError> {
-        let data = read_file(file_path).map_err(|_e| CryptoError::KeyLoad)?;
-        let secret_key =
-            casper_types::SecretKey::from_pem(data).map_err(|_e| CryptoError::FailedToParseKey)?;
-        Ok(Self(secret_key))
+    pub fn from_file<P: AsRef<Path>>(file_path: P) -> Result<Self, CryptoError> {
+        casper_types::SecretKey::from_file(file_path)
+            .map(Self)
+            .map_err(|error| error.into())
     }
 }

kairos-cli/bin/crypto/signer.rs

@@ -1,10 +1,10 @@
-use std::path::PathBuf;
+use std::path::Path;
 
 use super::private_key::CasperPrivateKey;
 use super::public_key::CasperPublicKey;
 use crate::crypto::error::CryptoError;
 use casper_types::bytesrepr::ToBytes;
-use casper_types::{crypto, PublicKey, SecretKey};
+use casper_types::{crypto, PublicKey};
 
 pub struct CasperSigner {
     secret_key: CasperPrivateKey,
@@ -13,28 +13,16 @@ pub struct CasperSigner {
 
 #[allow(unused)]
 impl CasperSigner {
-    fn from_key_raw(secret_key: CasperPrivateKey) -> Self {
+    pub fn from_file<P: AsRef<Path>>(file_path: P) -> Result<Self, CryptoError> {
+        let secret_key = CasperPrivateKey::from_file(file_path)?;
+
         // Derive the public key.
         let public_key = CasperPublicKey::from_key(PublicKey::from(&secret_key.0));
 
-        CasperSigner {
+        Ok(CasperSigner {
             secret_key,
             public_key,
-        }
-    }
-
-    pub fn from_file(secret_key_path: &str) -> Result<Self, CryptoError> {
-        let secret_key =
-            SecretKey::from_file(secret_key_path).map_err(|_e| CryptoError::FailedToParseKey)?;
-
-        Ok(Self::from_key_raw(CasperPrivateKey(secret_key)))
-    }
-
-    pub fn from_key_pathbuf(secret_key_path: PathBuf) -> Result<Self, CryptoError> {
-        let private_key_path_str: &str = secret_key_path.to_str().ok_or(CryptoError::KeyLoad)?;
-        let private_key = CasperPrivateKey::from_file(private_key_path_str)?;
-
-        Ok(Self::from_key_raw(private_key))
+        })
     }
 
     pub fn get_public_key(&self) -> CasperPublicKey {

kairos-cli/tests/cli_tests.rs

@@ -77,7 +77,7 @@ fn deposit_invalid_private_key_path() {
         .arg(secret_key_path);
     cmd.assert()
         .failure()
-        .stderr(predicates::str::contains("failed to load key from file"));
+        .stderr(predicates::str::contains("failed to parse private key"));
 }
 
 #[test]