Allow users to use ~ in their key paths for real this time

Previously, it was observed that using a tilde to represent a user's
home directory wasn't resolving correctly.
With this change, we're explicitly expanding the path to fully resolve
the location.

Fixes #21

Cargo.toml

@@ -11,6 +11,7 @@ crate-type = ["cdylib"]
 [dependencies]
 openssl = { version = "0.10", features = ["vendored"] }
 pyo3 = "0.22"
+shellexpand = "2.1"
 # ssh2 = "0.9"
 # temporary until ssh2#312 makes it into a release. probably 0.9.5
 ssh2 = { git = "https://github.com/alexcrichton/ssh2-rs", branch = "master" }

src/connection.rs

@@ -252,15 +252,18 @@ impl Connection {
         let private_key = private_key.unwrap_or("");
         // if private_key is set, use it to authenticate
         if !private_key.is_empty() {
+            // If a user uses a tilde to represent the home directory,
+            // replace it with the actual home directory
+            let private_key = shellexpand::tilde(private_key).into_owned();
             // if a password is set, use it to decrypt the private key
             if !password.is_empty() {
                 session
-                    .userauth_pubkey_file(username, None, Path::new(private_key), Some(password))
+                    .userauth_pubkey_file(username, None, Path::new(&private_key), Some(password))
                     .map_err(|e| PyErr::new::<AuthenticationError, _>(format!("{}", e)))?;
             } else {
                 // otherwise, try using the private key without a passphrase
                 session
-                    .userauth_pubkey_file(username, None, Path::new(private_key), None)
+                    .userauth_pubkey_file(username, None, Path::new(&private_key), None)
                     .map_err(|e| PyErr::new::<AuthenticationError, _>(format!("{}", e)))?;
             }
         } else if !password.is_empty() {

tests/test_connection.py

@@ -26,6 +26,19 @@ def test_key_auth():
     assert Connection(host="localhost", port=8022, private_key="tests/data/test_key")
 
 
+def test_key_in_user_home():
+    """Test that we can establish a connection with a key in the user's home directory."""
+    # temporarily copy the key to the user's home directory
+    key_path = Path("tests/data/test_key")
+    new_path = Path.home() / ".ssh" / "test_key"
+    new_path.parent.mkdir(exist_ok=True)
+    key_path.rename(new_path)
+    try:
+        assert Connection(host="localhost", port=8022, private_key="~/.ssh/test_key")
+    finally:
+        new_path.rename(key_path)
+
+
 def test_key_with_password_auth():
     """Test that we can establish a connection with key-based authentication and a password."""
     assert Connection(