feat(serde): add serde_with support for serialization

Optionally provide serialization with serde_with. Since the types already provide `Display` and `FromStr` we can use `serde_with` to provide `serde` support. This will allow storing strkeys in config files with their types and not just `String`.

Cargo.toml

@@ -13,6 +13,7 @@ rust-version = "1.81.0"
 [features]
 default = []
 cli = ["dep:clap"]
+serde_with = ["dep:serde_with"]
 
 [[bin]]
 name = "stellar-strkey"
@@ -24,8 +25,11 @@ doctest = false
 crate-git-revision = "0.0.6"
 
 [dev-dependencies]
-proptest = "1.0.0"
+proptest ="1.0.0"
+serde = { version = "1.0.214", features = ["derive"] }
+toml = "0.8.19"
 
 [dependencies]
 data-encoding = { version = "2.6.0", default-features = false, features = ["alloc"] }
 clap = { version = "4.2.4", default-features = false, features = ["std", "derive", "usage", "help"], optional = true }
+serde_with = { version = "3.11.0", optional = true }

src/ed25519.rs

@@ -11,6 +11,10 @@ use core::{
 };
 
 #[derive(Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
+#[cfg_attr(
+    feature = "serde_with",
+    derive(serde_with::SerializeDisplay, serde_with::DeserializeFromStr)
+)]
 pub struct PrivateKey(pub [u8; 32]);
 
 impl Debug for PrivateKey {
@@ -66,6 +70,10 @@ impl FromStr for PrivateKey {
 }
 
 #[derive(Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
+#[cfg_attr(
+    feature = "serde_with",
+    derive(serde_with::SerializeDisplay, serde_with::DeserializeFromStr)
+)]
 pub struct PublicKey(pub [u8; 32]);
 
 impl Debug for PublicKey {
@@ -121,6 +129,10 @@ impl FromStr for PublicKey {
 }
 
 #[derive(Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
+#[cfg_attr(
+    feature = "serde_with",
+    derive(serde_with::SerializeDisplay, serde_with::DeserializeFromStr)
+)]
 pub struct MuxedAccount {
     pub ed25519: [u8; 32],
     pub id: u64,
@@ -192,6 +204,10 @@ impl FromStr for MuxedAccount {
 ///
 /// The payload must not have a size larger than u32::MAX.
 #[derive(Clone, Hash, PartialEq, Eq, PartialOrd, Ord)]
+#[cfg_attr(
+    feature = "serde_with",
+    derive(serde_with::SerializeDisplay, serde_with::DeserializeFromStr)
+)]
 pub struct SignedPayload {
     pub ed25519: [u8; 32],
     pub payload: Vec<u8>,

src/strkey.rs

@@ -12,6 +12,10 @@ use crate::{
 };
 
 #[derive(Clone, Hash, PartialEq, Eq, PartialOrd, Ord, Debug)]
+#[cfg_attr(
+    feature = "serde_with",
+    derive(serde_with::SerializeDisplay, serde_with::DeserializeFromStr)
+)]
 pub enum Strkey {
     PublicKeyEd25519(ed25519::PublicKey),
     PrivateKeyEd25519(ed25519::PrivateKey),
@@ -73,6 +77,10 @@ impl FromStr for Strkey {
 }
 
 #[derive(Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
+#[cfg_attr(
+    feature = "serde_with",
+    derive(serde_with::SerializeDisplay, serde_with::DeserializeFromStr)
+)]
 pub struct PreAuthTx(pub [u8; 32]);
 
 impl Debug for PreAuthTx {
@@ -125,6 +133,10 @@ impl FromStr for PreAuthTx {
 }
 
 #[derive(Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
+#[cfg_attr(
+    feature = "serde_with",
+    derive(serde_with::SerializeDisplay, serde_with::DeserializeFromStr)
+)]
 pub struct HashX(pub [u8; 32]);
 
 impl Debug for HashX {
@@ -177,6 +189,10 @@ impl FromStr for HashX {
 }
 
 #[derive(Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
+#[cfg_attr(
+    feature = "serde_with",
+    derive(serde_with::SerializeDisplay, serde_with::DeserializeFromStr)
+)]
 pub struct Contract(pub [u8; 32]);
 
 impl Debug for Contract {

tests/tests.rs

@@ -443,5 +443,21 @@ fn assert_convert_roundtrip(s: &str, strkey: &Strkey) {
     let strkey_result = Strkey::from_string(s).unwrap();
     assert_eq!(&strkey_result, strkey);
     let str_result = format!("{strkey}");
-    assert_eq!(s, str_result)
+    assert_eq!(s, str_result);
+    #[cfg(feature = "serde_with")]
+    test_serde_with(s, strkey);
+}
+
+#[cfg(feature = "serde_with")]
+fn test_serde_with(s: &str, strkey: &Strkey) {
+    #[derive(Debug, serde::Serialize, serde::Deserialize)]
+    struct StrKey {
+        strkey: Strkey,
+    }
+    let str_key_s = toml::to_string(&StrKey {
+        strkey: strkey.clone(),
+    })
+    .unwrap();
+    let str_key: StrKey = toml::from_str(&str_key_s).unwrap();
+    assert_eq!(strkey, &str_key.strkey);
 }