Skip serialization for empty fields

Cargo.lock

@@ -219,6 +219,8 @@ dependencies = [
  "ipnetwork",
  "log",
  "pnet",
+ "serde",
+ "serde_yaml",
  "tokio",
 ]
 
@@ -257,6 +259,12 @@ dependencies = [
  "log",
 ]
 
+[[package]]
+name = "equivalent"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5443807d6dff69373d433ab9ef5378ad8df50ca6298caf15de6e52e24aaf54d5"
+
 [[package]]
 name = "form_urlencoded"
 version = "1.2.1"
@@ -329,6 +337,12 @@ version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d2fabcfbdc87f4758337ca535fb41a6d701b65693ce38287d856d1674551ec9b"
 
+[[package]]
+name = "hashbrown"
+version = "0.14.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e5274423e17b7c9fc20b6e7e208532f9b19825d82dfd615708b70edd83df41f1"
+
 [[package]]
 name = "heck"
 version = "0.4.1"
@@ -380,6 +394,16 @@ dependencies = [
  "unicode-normalization",
 ]
 
+[[package]]
+name = "indexmap"
+version = "2.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "93ead53efc7ea8ed3cfb0c79fc8023fbb782a5432b52830b6518941cebe6505c"
+dependencies = [
+ "equivalent",
+ "hashbrown",
+]
+
 [[package]]
 name = "ipnet"
 version = "2.9.0"
@@ -401,6 +425,12 @@ version = "1.70.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7943c866cc5cd64cbc25b2e01621d07fa8eb2a1a23160ee81ce38704e97b8ecf"
 
+[[package]]
+name = "itoa"
+version = "1.0.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "49f1f14873335454500d59611f1cf4a4b0f786f9ac11f4312a78e4cf2566695b"
+
 [[package]]
 name = "lazy_static"
 version = "1.5.0"
@@ -674,6 +704,12 @@ version = "0.1.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "719b953e2095829ee67db738b3bfa9fa368c94900df327b3f07fe6e794d2fe1f"
 
+[[package]]
+name = "ryu"
+version = "1.0.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f3cb5ba0dc43242ce17de99c180e96db90b235b8a9fdc9543c96d2209116bd9f"
+
 [[package]]
 name = "serde"
 version = "1.0.209"
@@ -694,6 +730,19 @@ dependencies = [
  "syn 2.0.72",
 ]
 
+[[package]]
+name = "serde_yaml"
+version = "0.9.34+deprecated"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6a8b1a1a2ebf674015cc02edccce75287f1a0130d394307b36743c2f5d504b47"
+dependencies = [
+ "indexmap",
+ "itoa",
+ "ryu",
+ "serde",
+ "unsafe-libyaml",
+]
+
 [[package]]
 name = "shlex"
 version = "1.3.0"
@@ -890,6 +939,12 @@ dependencies = [
  "tinyvec",
 ]
 
+[[package]]
+name = "unsafe-libyaml"
+version = "0.2.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "673aac59facbab8a9007c7f6108d11f63b603f7cabff99fabf650fea5c32b861"
+
 [[package]]
 name = "url"
 version = "2.5.2"

Cargo.toml

@@ -12,4 +12,6 @@ hex = "0.4.3"
 ipnetwork = "0.20.0"
 log = "0.4.22"
 pnet = "0.35.0"
+serde = { version = "1.0.209", features = ["derive"] }
+serde_yaml = "0.9.34"
 tokio = { version = "1.39.3", features = ["macros", "net", "rt-multi-thread"] }

src/main.rs

@@ -24,6 +24,7 @@ use log::{
     Level,
 };
 use pnet;
+use serde::Serialize;
 use std::net::SocketAddrV6;
 use tokio::net::UdpSocket;
 
@@ -39,6 +40,43 @@ struct Cli {
     interface: String,
 }
 
+#[derive(Serialize)]
+struct MessageMap {
+    #[serde(skip_serializing_if = "Option::is_none")]
+    server_id: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    domain_name_servers: Option<Vec<String>>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    domain_search_list: Option<Vec<String>>,
+}
+
+impl MessageMap {
+    fn new() -> Self {
+        Self {
+            server_id: None,
+            domain_name_servers: None,
+            domain_search_list: None,
+        }
+    }
+}
+
+fn message_to_map(msg: &Message) -> MessageMap {
+    let mut map = MessageMap::new();
+
+    if let Some(DhcpOption::ServerId(server_id)) = &msg.opts().get(OptionCode::ServerId) {
+        map.server_id = Some(hex::encode(&server_id));
+    }
+
+    if let Some(DhcpOption::DomainNameServers(domain_name_servers)) = &msg.opts().get(OptionCode::DomainNameServers) {
+        map.domain_name_servers = Some(domain_name_servers.iter().map(|a| a.to_string()).collect());
+    }
+    if let Some(DhcpOption::DomainSearchList(domain_search_list)) = &msg.opts().get(OptionCode::DomainSearchList) {
+        map.domain_search_list = Some(domain_search_list.iter().map(|n| n.to_string()).collect());
+    }
+
+    return map;
+}
+
 #[tokio::main]
 async fn main() -> Result<()>{
     env_logger::init();
@@ -115,22 +153,10 @@ async fn main() -> Result<()>{
         }
     };
 
-    if let Some(DhcpOption::ServerId(server_id)) = &response_msg.opts().get(OptionCode::ServerId) {
-        println!("server_id: {}", hex::encode(&server_id));
-    }
-
-    if let Some(DhcpOption::DomainNameServers(domain_name_servers)) = &response_msg.opts().get(OptionCode::DomainNameServers) {
-        println!("domain_name_servers:");
-        for domain_name_server in domain_name_servers {
-            println!("  - {}", domain_name_server);
-        }
-    }
-    if let Some(DhcpOption::DomainSearchList(domain_search_list)) = &response_msg.opts().get(OptionCode::DomainSearchList) {
-        println!("domain_search_list:");
-        for search_domain_name in domain_search_list {
-            println!("  - {}", search_domain_name);
-        }
-    }
+    let message_map = message_to_map(&response_msg);
+    let message_map_yaml = serde_yaml::to_string(&message_map)
+        .context("Unable to format message to yaml")?;
+    println!("{}", message_map_yaml);
 
     Ok(())
 }