Source: Only save Etag headers upon succesful requests

Additionally clear the Etags if the returned code is not 200 or 304.
Just to be extra safe. This is not as clean as it should, as this is
a temporary workaround until the API is reworked.

Related to #64

podcasts-data/src/models/source.rs

@@ -91,7 +91,7 @@ impl Source {
 
     /// Extract Etag and LastModifier from res, and update self and the
     /// corresponding db row.
-    fn update_etag(&mut self, res: &Response) -> Result<(), DataError> {
+    fn update_etag(mut self, res: &Response) -> Result<Self, DataError> {
         let headers = res.headers();
 
         let etag = headers.get::<ETag>().map(|x| x.tag());
@@ -100,10 +100,24 @@ impl Source {
         if (self.http_etag() != etag) || (self.last_modified != lmod) {
             self.set_http_etag(etag);
             self.set_last_modified(lmod);
-            self.save()?;
+            self = self.save()?;
         }
 
-        Ok(())
+        Ok(self)
+    }
+
+    /// Clear the `HTTP` `Etag` and `Last-modified` headers.
+    fn clear_etags(mut self) -> Result<Self, DataError> {
+        if self.http_etag().is_some() || self.last_modified().is_some() {
+            debug!("Source etags before clear: {:#?}", &self);
+            self.http_etag = None;
+            self.last_modified = None;
+            self = self.save()?;
+            debug!("Source etags after clear: {:#?}", &self);
+            info!("Etag fields cleared succesfully for Source: {}", self.uri);
+        }
+
+        Ok(self)
     }
 
     fn make_err(self, context: &str, code: StatusCode) -> DataError {
@@ -121,14 +135,19 @@ impl Source {
     // 410: Feed deleted
     // TODO: Rething this api,
     fn match_status(mut self, res: Response) -> Result<Response, DataError> {
-        self.update_etag(&res)?;
         let code = res.status();
+        match code {
+            // If request is succesful save the etag
+            StatusCode::NotModified | StatusCode::Ok => self = self.update_etag(&res)?,
+            // Clear the Etag/lmod else
+            _ => self = self.clear_etags()?,
+        };
 
         match code {
             StatusCode::NotModified => return Err(self.make_err("304: skipping..", code)),
             StatusCode::MovedPermanently => {
                 error!("Feed was moved permanently.");
-                self.handle_301(&res)?;
+                self = self.update_url(&res)?;
                 return Err(DataError::F301(self));
             }
             StatusCode::TemporaryRedirect => debug!("307: Temporary Redirect."),
@@ -140,21 +159,21 @@ impl Source {
             StatusCode::Gone => return Err(self.make_err("410: Feed was deleted..", code)),
             _ => info!("HTTP StatusCode: {}", code),
         };
+
         Ok(res)
     }
 
-    fn handle_301(&mut self, res: &Response) -> Result<(), DataError> {
+    fn update_url(mut self, res: &Response) -> Result<Self, DataError> {
         let headers = res.headers();
 
         if let Some(url) = headers.get::<Location>() {
             self.set_uri(url.to_string());
-            self.http_etag = None;
+            self = self.save()?;
-            self.last_modified = None;
-            self.save()?;
             info!("Feed url was updated succesfully.");
+            self = self.clear_etags()?;
         }
 
-        Ok(())
+        Ok(self)
     }
 
     /// Construct a new `Source` with the given `uri` and index it.