Add a Chromecast discovery example

dsheets · Nov 27, 2016 · acab2e5 · acab2e5
1 parent 60b5160
commit acab2e5
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Showing 4 changed files with 65 additions and 0 deletions.
diff --git a/examples/chromecast_discovery.rs b/examples/chromecast_discovery.rs
@@ -0,0 +1,17 @@
+extern crate mdns;
+
+use std::time::Duration;
+
+fn main() {
+    let duration = Duration::from_secs(5);
+
+    mdns::discover("_googlecast._tcp.local", Some(duration), |response| {
+        let addresses = response.records().filter_map(|record| {
+            if let mdns::RecordKind::A(addr) = record.kind { Some(addr) } else { None }
+        });
+
+        for address in addresses {
+            println!("found Chromecast on {}", address);
+        }
+    }).expect("error while performing Chromecast discovery");
+}
diff --git a/src/discover.rs b/src/discover.rs
@@ -0,0 +1,35 @@
+use {mDNS, Error, Response};
+use std::time::{SystemTime, Duration};
+
+use io;
+
+pub fn discover<F>(service_name: &str,
+                   duration: Option<Duration>,
+                   mut f: F) -> Result<(), Error>
+    where F: FnMut(Response) {
+    let mut io = io::Io::new()?;
+
+    let mut mdns = mDNS::new(service_name)?;
+    io.register(&mut mdns)?;
+
+    let finish_at = duration.map(|duration| SystemTime::now() + duration);
+
+    loop {
+        let poll_timeout = finish_at.map(|finish_at| {
+            finish_at.duration_since(SystemTime::now()).unwrap()
+        });
+
+        io.poll(&mut mdns, poll_timeout)?;
+
+        for response in mdns.responses() {
+            f(response)
+        }
+
+        if let Some(finish_at) = finish_at {
+            if SystemTime::now() >= finish_at {
+                break;
+            }
+        }
+    }
+    Ok(())
+}
diff --git a/src/lib.rs b/src/lib.rs
@@ -3,10 +3,12 @@
 pub use self::mdns::mDNS;
 pub use self::response::{Response, Record, RecordKind};
 pub use self::errors::{Error, ErrorKind};
+pub use self::discover::discover;
 
 pub mod mdns;
 pub mod response;
 pub mod errors;
+pub mod discover;
 mod io;
 
 extern crate mio;

diff --git a/src/response.rs b/src/response.rs
@@ -52,6 +52,17 @@ impl Response
             additional: packet.additional.iter().map(Record::from_resource_record).collect(),
         }
     }
+
+    pub fn records(&self) -> ::std::vec::IntoIter<&Record> {
+        let records: Vec<_> = vec![&self.answers, &self.nameservers, &self.additional].into_iter().flat_map(|c| c.iter()).collect();
+        records.into_iter()
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.answers.is_empty() &&
+            self.nameservers.is_empty() &&
+            self.additional.is_empty()
+    }
 }
 
 impl Record