Add guess_mime to BoxedEmbedMediaExt

Cargo.toml

@@ -62,6 +62,8 @@ rusqlite = { version = "0.32.0", optional = true }
 crc32fast = { version = "1", optional = true }
 ciborium = { version = "0.2", optional = true }
 
+mime_guess = { version = "2", optional = true }
+
 url = { version = "2", optional = true }
 thiserror = { version = "2", optional = true, default-features = false }
 mime = { version = "0.3", optional = true }

src/models/embed/v1.rs

@@ -323,6 +323,10 @@ pub trait BoxedEmbedMediaExt {
     fn with_dims(self, width: i32, height: i32) -> Self;
     fn with_mime(self, mime: impl Into<SmolStr>) -> Self;
     fn with_description(self, description: impl Into<ThinString>) -> Self;
+
+    /// Guess the mime type based on the URL extension
+    #[cfg(feature = "mime_guess")]
+    fn guess_mime(self) -> Self;
 }
 
 impl BoxedEmbedMediaExt for Box<EmbedMedia> {
@@ -355,6 +359,21 @@ impl BoxedEmbedMediaExt for Box<EmbedMedia> {
         self.description = Some(description.into());
         self
     }
+
+    #[cfg(feature = "mime_guess")]
+    fn guess_mime(mut self) -> Self {
+        use smol_str::ToSmolStr;
+
+        if self.mime.is_none() {
+            if let Some((_, ext)) = self.url.rsplit_once('.') {
+                if let Some(mime) = mime_guess::from_ext(ext).first() {
+                    self.mime = Some(ToSmolStr::to_smolstr(&mime));
+                }
+            }
+        }
+
+        self
+    }
 }
 
 pub trait VisitMedia {