Implement Deserialize trait for ServerAddress

See: #717

Impement the serde deserializer for the ServerAddress(Url) struct
based on the existing implementation of `from_str`.

nats/src/connector.rs

@@ -13,8 +13,11 @@
 
 use lazy_static::__Deref;
 use parking_lot::{Mutex, MutexGuard};
+use serde::de::{self, Visitor};
+use serde::{Deserialize, Deserializer};
 use std::collections::HashMap;
 use std::convert::TryFrom;
+use std::fmt::{self, Formatter};
 use std::io::prelude::*;
 use std::io::{self, BufReader, Error, ErrorKind};
 use std::net::{Shutdown, SocketAddr, TcpStream, ToSocketAddrs};
@@ -748,6 +751,26 @@ impl IntoServerList for io::Result<Vec<ServerAddress>> {
  }
 }
 
+struct ServerAddressVisitor;
+
+impl<'de> Visitor<'de> for ServerAddressVisitor {
+ type Value = ServerAddress;
+
+ fn expecting<'a>(&self, formatter: &mut Formatter<'a>) -> fmt::Result {
+ formatter.write_str("a valid URL")
+ }
+
+ fn visit_str<E: de::Error>(self, value: &str) -> Result<Self::Value, E> {
+ ServerAddress::from_str(value).map_err(|err| E::custom(format!("{}", err)))
+ }
+}
+
+impl<'de> Deserialize<'de> for ServerAddress {
+ fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
+ deserializer.deserialize_str(ServerAddressVisitor)
+ }
+}
+
 #[cfg(test)]
 mod tests {
  use super::*;
@@ -789,4 +812,24 @@ mod tests {
  matches!(address.auth(), AuthStyle::UserPass(username, password) if &username == "myuser" && &password == "mypass")
  );
  }
+
+ #[test]
+ fn deserialize_valid_server_address() {
+ let serialized = "\"nats://myuser:mypass@localhost:4222\"";
+ let address = ServerAddress::from_str("nats://myuser:mypass@localhost:4222").unwrap();
+
+ assert_eq!(
+ serde_json::from_str::<ServerAddress>(serialized).unwrap(),
+ address
+ );
+ }
+
+ #[test]
+ fn deserialize_invalid_server_address() {
+ let serialized = "\"this is not the address\"";
+ let result = serde_json::from_str::<ServerAddress>(serialized);
+
+ assert!(result.is_err());
+ assert!(format!("{}", result.unwrap_err()).contains("NATS server URL is invalid"));
+ }
 }