Added documentation about service name length <=15 accoring to #427

src/lib.rs

@@ -74,7 +74,21 @@
 //! // Create a daemon
 //! let mdns = ServiceDaemon::new().expect("Failed to create daemon");
 //!
+//! // Recommended: Setup a monitor connection to receive events, especially errors from the daemon thread.
+//! let receiver = mdns.monitor().expect("Failed to monitor daemon");
+//! std::thread::spawn(move || {
+//!     while let Ok(event) = receiver.recv() {
+//!         match event {
+//!             mdns_sd::DaemonEvent::Error(error) => {
+//!                 eprintln!("Daemon error: {error}");
+//!             }
+//!             _ => {}
+//!         }
+//!     }
+//! });
+//!
 //! // Create a service info.
+//! // ❗ Make sure that the service name: "mdns-sd-my-test" is not longer than the max length limit. (15 characters by default)
 //! let service_type = "_mdns-sd-my-test._udp.local.";
 //! let instance_name = "my_instance";
 //! let ip = "192.168.1.12";

src/service_daemon.rs

@@ -29,7 +29,7 @@
 // in Service Discovery, the basic data structure is "Service Info". One Service Info
 // corresponds to a set of DNS Resource Records.
 #[cfg(feature = "logging")]
-use crate::log::{debug, trace};
+use crate::log::{debug, error, trace};
 use crate::{
     dns_cache::{current_time_millis, DnsCache},
     dns_parser::{
@@ -1863,7 +1863,7 @@ impl Zeroconf {
     fn register_service(&mut self, mut info: ServiceInfo) {
         // Check the service name length.
         if let Err(e) = check_service_name_length(info.get_type(), self.service_name_len_max) {
-            debug!("check_service_name_length: {}", &e);
+            error!("check_service_name_length: {}", &e);
             self.notify_monitors(DaemonEvent::Error(e));
             return;
         }

src/service_info.rs

@@ -87,6 +87,8 @@ fn escape_instance_name(name: &str) -> String {
 /// as well as A (IPv4 Address) and AAAA (IPv6 Address) records.
 #[derive(Debug, Clone)]
 pub struct ServiceInfo {
+    // With default settings service name length must be <= 15 bytes
+    // so "_abcdefghijklmno._udp.local." would be valid but "_abcdefghijklmnop._udp.local." is not
     ty_domain: String, // <service>.<domain>
 
     /// See RFC6763 section 7.1 about "Subtypes":
@@ -128,6 +130,10 @@ impl ServiceInfo {
     ///
     /// `ty_domain` is the service type and the domain label, for example
     /// "_my-service._udp.local.".
+    /// With default settings service name length must be <= 15 bytes
+    /// so "_abcdefghijklmno._udp.local." would be valid but "_abcdefghijklmnop._udp.local." is not  
+    /// ❗ **This will fail with an error log which may not be noticed unless you properly setup logging**.
+    /// It is recommended to setup a monitor connection via `ServiceDaemon::monitor()`
     ///
     /// `my_name` is the instance name, without the service type suffix.
     /// It allows dots (`.`) and backslashes (`\`).