logtail: support serde

Signed-off-by: Christine Dodrill <me@christine.website>

Cargo.lock

@@ -537,6 +537,7 @@ version = "0.1.0"
 dependencies = [
  "hex",
  "rand 0.8.4",
+ "serde",
  "sha2",
 ]
 

crates/logtail/Cargo.toml

@@ -3,9 +3,18 @@ name = "logtail"
 version = "0.1.0"
 edition = "2018"
 
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+# See more keys and their definitions at
+# https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[features]
+default = [ "serde-ser" ]
+serde-ser = [ "serde" ]
 
 [dependencies]
 hex = "0.4"
 rand = "0"
 sha2 = "0.9"
+
+[dependencies.serde]
+version = "1"
+optional = true

crates/logtail/src/lib.rs

@@ -10,6 +10,9 @@ use std::fmt;
 #[derive(Clone, PartialEq, Eq)]
 pub struct PrivateID([u8; SHA256_SIZE]);
 
+#[cfg(feature = "serde-ser")]
+mod serde;
+
 impl PrivateID {
     /// Safely generate a new PrivateId for use in Config objects.
     /// You should persist this across runs of an instance of your app, so that

crates/logtail/src/serde.rs

@@ -0,0 +1,67 @@
+use super::{PrivateID, PublicID};
+use serde::{de, Serialize, Serializer};
+use std::fmt;
+
+impl Serialize for PrivateID {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_str(&self.as_hex())
+    }
+}
+
+struct PrivateIDVisitor;
+
+impl<'de> de::Visitor<'de> for PrivateIDVisitor {
+    type Value = PrivateID;
+
+    fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        formatter.write_str("a base-16 formatted ID as a string")
+    }
+
+    fn visit_str<E>(self, id: &str) -> Result<Self::Value, E>
+    where
+        E: de::Error,
+    {
+        match PrivateID::from_hex(id.to_string()) {
+            Ok(id) => Ok(id),
+            Err(_) => Err(de::Error::invalid_value(
+                de::Unexpected::Str(id),
+                &"a base-16 32 byte ID",
+            )),
+        }
+    }
+}
+
+impl Serialize for PublicID {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_str(&self.as_hex())
+    }
+}
+
+struct PublicIDVisitor;
+
+impl<'de> de::Visitor<'de> for PublicIDVisitor {
+    type Value = PublicID;
+
+    fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        formatter.write_str("a base-16 formatted ID as a string")
+    }
+
+    fn visit_str<E>(self, id: &str) -> Result<Self::Value, E>
+    where
+        E: de::Error,
+    {
+        match PublicID::from_hex(id.to_string()) {
+            Ok(id) => Ok(id),
+            Err(_) => Err(de::Error::invalid_value(
+                de::Unexpected::Str(id),
+                &"a base-16 32 byte ID",
+            )),
+        }
+    }
+}