Add mDNS advertise example (#582)

Author: piotrpdev

CHANGELOG.md

@@ -23,6 +23,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - OTA: Allow specifying image size to speed up erase
 - Bluetooth: New methods `EspBleGap::start_scanning` and `EspBleGap::stop_scanning`
 - New example, `bt_ble_gap_scanner` to demonstrate usage of added ble scanning methods
+- New example, `mdns_advertise` to demonstrate mDNS service advertisement
 
 ## [0.51.0] - 2025-01-15
 

examples/mdns_advertise.rs

@@ -0,0 +1,113 @@
+//! Simple mDNS advertise example.
+//!
+//! See the comment below as to how to build the example with ESP IDF 5+.
+
+#![allow(unknown_lints)]
+#![allow(unexpected_cfgs)]
+
+pub fn main() {
+    #[cfg(esp_idf_version_major = "4")]
+    example::main().unwrap();
+
+    // Note that ESP IDF mDNS IS available on ESP IDF >= 5 too
+    // It is just that it is now an external component, so to use it, you need
+    // to put the following snippet at the end of the `Cargo.toml` file of your binary crate:
+    //
+    // ```toml
+    // [[package.metadata.esp-idf-sys.extra_components]]
+    // remote_component = { name = "espressif/mdns", version = "1.8.2" }
+    // ```
+    #[cfg(not(esp_idf_version_major = "4"))]
+    panic!("This example only compiles on ESP IDF 4. Check the comments in the example how to compile it on ESP IDF 5+")
+}
+
+#[cfg(esp_idf_version_major = "4")]
+pub mod example {
+    use esp_idf_hal::io::Write;
+    use esp_idf_svc::eventloop::EspSystemEventLoop;
+    use esp_idf_svc::hal::peripherals::Peripherals;
+    use esp_idf_svc::http::server::EspHttpServer;
+    use esp_idf_svc::http::Method;
+    use esp_idf_svc::log::EspLogger;
+    use esp_idf_svc::mdns::EspMdns;
+    use esp_idf_svc::nvs::EspDefaultNvsPartition;
+    use esp_idf_svc::wifi::*;
+
+    use log::info;
+
+    const SSID: &str = env!("WIFI_SSID");
+    const PASSWORD: &str = env!("WIFI_PASS");
+    static INDEX_HTML: &str = include_str!("http_server_page.html");
+
+    pub fn main() -> anyhow::Result<()> {
+        esp_idf_svc::sys::link_patches();
+        EspLogger::initialize_default();
+
+        // Setup Wifi
+        let peripherals = Peripherals::take()?;
+        let sys_loop = EspSystemEventLoop::take()?;
+        let nvs = EspDefaultNvsPartition::take()?;
+        let mut wifi = BlockingWifi::wrap(
+            EspWifi::new(peripherals.modem, sys_loop.clone(), Some(nvs))?,
+            sys_loop,
+        )?;
+        connect_wifi(&mut wifi)?;
+
+        // Setup HTTP server
+        let server_config = esp_idf_svc::http::server::Configuration::default();
+        let mut server = EspHttpServer::new(&server_config)?;
+        server.fn_handler("/", Method::Get, |req| {
+            req.into_ok_response()?
+                .write_all(INDEX_HTML.as_bytes())
+                .map(|_| ())
+        })?;
+
+        // Setup mDNS
+        let mut mdns = EspMdns::take()?;
+        mdns.set_hostname("esp-advertiser")?;
+
+        // Advertise the HTTP server
+        mdns.add_service(
+            Some("ESP HTTP Server"),
+            "_http",
+            "_tcp",
+            server_config.http_port,
+            &[],
+        )?;
+
+        // Keep the wifi, http server, and mDNS running beyond when main() returns (forever)
+        // Do not call this if you ever want to stop or access them later.
+        // Otherwise you can either add an infinite loop so the main task
+        // never returns, or you can move them to another thread.
+        // https://doc.rust-lang.org/stable/core/mem/fn.forget.html
+        core::mem::forget(wifi);
+        core::mem::forget(server);
+        core::mem::forget(mdns);
+
+        Ok(())
+    }
+
+    fn connect_wifi(wifi: &mut BlockingWifi<EspWifi<'static>>) -> anyhow::Result<()> {
+        let wifi_configuration: Configuration = Configuration::Client(ClientConfiguration {
+            ssid: SSID.try_into().unwrap(),
+            bssid: None,
+            auth_method: AuthMethod::WPA2Personal,
+            password: PASSWORD.try_into().unwrap(),
+            channel: None,
+            ..Default::default()
+        });
+
+        wifi.set_configuration(&wifi_configuration)?;
+
+        wifi.start()?;
+        info!("Wifi started");
+
+        wifi.connect()?;
+        info!("Wifi connected");
+
+        wifi.wait_netif_up()?;
+        info!("Wifi netif up");
+
+        Ok(())
+    }
+}