diff --git a/src/main.rs b/src/main.rs
index 9606824..2b8ec99 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -4,6 +4,7 @@ use std::sync::{Mutex, RwLock};
 use std::collections::VecDeque;
 use rustorm::{pool::Pool, DbError};
 use chrono::offset::Utc;
+use reqwest::header::{IF_NONE_MATCH, IF_MODIFIED_SINCE, ETAG, LAST_MODIFIED, USER_AGENT};
 
 mod config;
 use config::{Config, CalendarOptions};
@@ -46,22 +47,57 @@ impl Resources {
             Some(next) => next,
             None => return Ok(()),
         };
-        let tx = self.transaction()?;
 
-        let cal: Option<Calendar> =
-            tx.query("SELECT * FROM calendar WHERE id=$1", &[&id])?;
-        if cal.is_none() {
-            tx.insert(&[&new::Calendar {
-                id: id.clone(),
-                url: cal_opts.url.clone(),
-                last_fetch: Utc::now(),
-            }])?;
-        } else {
-            tx.exec("UPDATE calendar SET last_fetch=$2 WHERE id=$1", &[&id, &"NOW()"])?;
+        let (etag, last_modified) = {
+            let tx = self.transaction()?;
+            let cal: Option<Calendar> =
+                tx.query("SELECT * FROM calendar WHERE id=$1", &[&id])?;
+            let result = match cal {
+                None => {
+                    tx.insert(&[&new::Calendar {
+                        id: id.clone(),
+                        url: cal_opts.url.clone(),
+                        last_fetch: Utc::now(),
+                    }])?;
+                    (None, None)
+                }
+                Some(cal) => {
+                    tx.exec("UPDATE calendar SET last_fetch=$2 WHERE id=$1", &[&id, &Utc::now()])?;
+                    (cal.etag, cal.last_modified)
+                }
+            };
+            tx.commit()?;
+            result
+        };
+
+        let mut req = self.http_client.get(&cal_opts.url)
+            .header(USER_AGENT, "Ticker/0.0.0");
+        match etag {
+            Some(etag) => req = req.header(IF_NONE_MATCH, etag),
+            None => (),
+        }
+        match last_modified {
+            Some(last_modified) => req = req.header(IF_MODIFIED_SINCE, last_modified),
+            None => (),
+        }
+        let mut res = req.send()?;
+
+        println!("{} {}", res.status(), cal_opts.url);
+        if res.status() != 200 {
+            let tx = self.transaction()?;
+            let msg = format!("HTTP {}", res.status());
+            tx.exec("UPDATE calendar SET last_success=$2, error_message=$3 WHERE id=$1", &[&id, &Utc::now(), &msg])?;
+            tx.commit()?;
+            return Ok(())
         }
 
-        let mut res = self.http_client.get(&cal_opts.url).send()?;
-        println!("{} {} {:?}", res.status(), cal_opts.url, res.headers());
+        let etag = res.headers().get(ETAG)
+            .and_then(|v| v.to_str().ok());
+        let last_modified = res.headers().get(LAST_MODIFIED)
+            .and_then(|v| v.to_str().ok());
+
+        let tx = self.transaction()?;
+        tx.exec("UPDATE calendar SET last_success=$2, error_message=NULL, etag=$3, last_modified=$4 WHERE id=$1", &[&id, &Utc::now(), &etag, &last_modified])?;
 
         let mut p = Parser::new();
         let mut buf = [0; 1024];
@@ -81,7 +117,7 @@ impl Resources {
         }
 
         tx.commit()?;
-        
+
         Ok(())
     }
 }