Make channel/item image optional; change item length type

This allows more back-ends to be compatible.

src/backends.rs

@@ -64,7 +64,7 @@ pub(crate) struct Channel {
     pub(crate) categories: Vec<String>,
 
     /// The URL of the image/logo/avatar of a channel.
-    pub(crate) image: Url,
+    pub(crate) image: Option<Url>,
 
     /// The contained content items.
     pub(crate) items: Vec<Item>,
@@ -99,7 +99,7 @@ pub(crate) struct Item {
     pub(crate) keywords: Vec<String>,
 
     /// The URL of the image of the item.
-    pub(crate) image: Url,
+    pub(crate) image: Option<Url>,
 
     /// The timestamp the item was last updated.
     pub(crate) updated_at: DateTime<Utc>,
@@ -117,5 +117,5 @@ pub(crate) struct Enclosure {
     pub(crate) mime_type: String,
 
     /// The length of the enclosed media content (in bytes).
-    pub(crate) length: u32,
+    pub(crate) length: u64,
 }

src/backends/mixcloud.rs

@@ -22,7 +22,7 @@ const API_BASE_URL: &str = "https://api.mixcloud.com";
 const FILES_BASE_URL: &str = "https://www.mixcloud.com";
 
 /// The default bitrate used by Mixcloud.
-const DEFAULT_BITRATE: u32 = 64 * 1024;
+const DEFAULT_BITRATE: u64 = 64 * 1024;
 
 /// The default file (MIME) type used by Mixcloud.
 const DEFAULT_FILE_TYPE: &str = "audio/mpeg";
@@ -190,7 +190,7 @@ impl From<UserWithCloudcasts> for Channel {
             description: user.biog,
             author: Some(user.name),
             categories,
-            image: user.pictures.large,
+            image: Some(user.pictures.large),
             items,
         }
     }
@@ -225,7 +225,7 @@ impl From<Cloudcast> for Item {
             duration: Some(cloudcast.audio_length),
             guid: cloudcast.slug,
             keywords,
-            image: cloudcast.pictures.large,
+            image: Some(cloudcast.pictures.large),
             updated_at: cloudcast.updated_time,
         }
     }
@@ -234,8 +234,8 @@ impl From<Cloudcast> for Item {
 /// Returns the estimated file size in bytes for a given duration.
 ///
 /// This uses the default bitrate (see [`DEFAULT_BITRATE`]) which is in B/s.
-fn estimated_file_size(duration: u32) -> u32 {
-    DEFAULT_BITRATE * duration / 8
+fn estimated_file_size(duration: u32) -> u64 {
+    DEFAULT_BITRATE * duration as u64 / 8
 }
 
 /// Fetches the user from the URL.

src/feed.rs

@@ -34,10 +34,10 @@ pub(crate) fn construct(backend_id: &str, config: &Config, channel: Channel) ->
         " ",
         env!("CARGO_PKG_VERSION")
     ));
-    let image = ImageBuilder::default()
-        .link(channel.image.clone())
-        .url(channel.image.clone())
-        .build();
+    let image = channel
+        .image
+        .clone()
+        .map(|url| ImageBuilder::default().link(url.clone()).url(url).build());
     let items = channel
         .items
         .into_iter()
@@ -52,7 +52,7 @@ pub(crate) fn construct(backend_id: &str, config: &Config, channel: Channel) ->
                 .map(|cat| ITunesCategoryBuilder::default().text(cat).build())
                 .collect::<Vec<_>>(),
         )
-        .image(Some(channel.image.to_string()))
+        .image(channel.image.map(String::from))
         .explicit(Some(String::from("no")))
         .summary(Some(channel.description.clone()))
         .build();
@@ -64,7 +64,7 @@ pub(crate) fn construct(backend_id: &str, config: &Config, channel: Channel) ->
         .category(category)
         .last_build_date(Some(last_build.to_rfc2822()))
         .generator(Some(generator))
-        .image(Some(image))
+        .image(image)
         .items(items)
         .itunes_ext(Some(itunes_ext))
         .build()
@@ -106,7 +106,7 @@ fn construct_item(
         .build();
     let keywords = item.keywords.join(", ");
     let itunes_ext = ITunesItemExtensionBuilder::default()
-        .image(Some(item.image.to_string()))
+        .image(item.image.map(String::from))
         .duration(item.duration.map(|dur| format!("{dur}")))
         .subtitle(item.description.clone())
         .keywords(Some(keywords))