Don't sniff media type in save_file()

src/activitypub/fetcher/fetchers.rs

@@ -12,7 +12,7 @@ use crate::http_signatures::create::{
     create_http_signature,
     HttpSignatureError,
 };
-use crate::utils::files::save_file;
+use crate::utils::files::{save_file, sniff_media_type};
 use crate::utils::urls::guess_protocol;
 use crate::webfinger::types::JsonResourceDescriptor;
 
@@ -118,8 +118,13 @@ pub async fn fetch_file(
     if file_data.len() > FILE_MAX_SIZE as usize {
         return Err(FetchError::OtherError("file is too large"));
     };
-    let (file_name, media_type) = save_file(file_data.to_vec(), output_dir, None)?;
-    Ok((file_name, media_type))
+    let maybe_media_type = sniff_media_type(&file_data);
+    let file_name = save_file(
+        file_data.to_vec(),
+        output_dir,
+        maybe_media_type.as_deref(),
+    )?;
+    Ok((file_name, maybe_media_type))
 }
 
 pub async fn perform_webfinger_query(

src/mastodon_api/uploads.rs

@@ -40,11 +40,18 @@ pub fn save_b64_file(
     if data.len() > UPLOAD_MAX_SIZE {
         return Err(UploadError::TooLarge);
     };
+    // Sniff media type if not provided
+    maybe_media_type = maybe_media_type.or(sniff_media_type(&data));
     if maybe_media_type.as_deref() == Some("image/svg+xml") {
         // Don't treat SVG files as images
         maybe_media_type = None;
     };
-    Ok(save_file(data, output_dir, maybe_media_type)?)
+    let file_name = save_file(
+        data,
+        output_dir,
+        maybe_media_type.as_deref(),
+    )?;
+    Ok((file_name, maybe_media_type))
 }
 
 pub fn save_validated_b64_file(
@@ -61,7 +68,6 @@ pub fn save_validated_b64_file(
     if !media_type.starts_with(media_type_prefix) {
         return Err(UploadError::InvalidMediaType);
     };
-    let (file_name, _) =
-        save_file(data, output_dir, Some(media_type.clone()))?;
+    let file_name = save_file(data, output_dir, Some(&media_type))?;
     Ok((file_name, media_type))
 }

src/utils/files.rs

@@ -43,17 +43,16 @@ pub fn set_file_permissions(file_path: &Path, mode: u32) -> Result<(), Error> {
     Ok(())
 }
 
+/// Save validated file to specified directory
 pub fn save_file(
     data: Vec<u8>,
     output_dir: &Path,
-    media_type: Option<String>,
-) -> Result<(String, Option<String>), Error> {
-    // Sniff media type if not provided
-    let media_type = media_type.or(sniff_media_type(&data));
-    let file_name = get_file_name(&data, media_type.as_deref());
+    media_type: Option<&str>,
+) -> Result<String, Error> {
+    let file_name = get_file_name(&data, media_type);
     let file_path = output_dir.join(&file_name);
     write_file(&data, &file_path)?;
-    Ok((file_name, media_type))
+    Ok(file_name)
 }
 
 pub fn get_file_url(instance_url: &str, file_name: &str) -> String {