fix: caculate range length of range header (#252)

Signed-off-by: Gaius <gaius.qi@gmail.com>

src/proxy/mod.rs

@@ -486,10 +486,15 @@ fn make_response_headers(
             format!(
                 "bytes {}-{}/{}",
                 range.start,
-                range.start + range.length,
+                range.start + range.length - 1,
                 download_task_started_response.content_length
             ),
         );
+
+        download_task_started_response.response_header.insert(
+            reqwest::header::CONTENT_LENGTH.to_string(),
+            range.length.to_string(),
+        );
     };
 
     hashmap_to_hyper_header_map(&download_task_started_response.response_header)

src/storage/content.rs

@@ -134,12 +134,13 @@ impl Content {
         range: Option<Range>,
     ) -> Result<impl AsyncRead> {
         if let Some(range) = range {
-            let offset = max(offset, range.start);
+            let target_offset = max(offset, range.start);
-            let length = min(offset + length - 1, range.start + range.length - 1) - offset + 1;
+            let target_length =
+                min(offset + length - 1, range.start + range.length - 1) - target_offset + 1;
 
             let mut f = File::open(self.dir.join(task_id)).await?;
-            f.seek(SeekFrom::Start(offset)).await?;
+            f.seek(SeekFrom::Start(target_offset)).await?;
-            return Ok(f.take(length));
+            return Ok(f.take(target_length));
         }
 
         let mut f = File::open(self.dir.join(task_id)).await?;

src/task/piece.rs

@@ -127,6 +127,7 @@ impl Piece {
                     break;
                 }
 
+                if offset + piece_length > range.start {
                     pieces.push(metadata::Piece {
                         number: number as u32,
                         offset,
@@ -139,6 +140,7 @@ impl Piece {
                         created_at: Utc::now().naive_utc(),
                         finished_at: None,
                     });
+                }
 
                 offset = (number + 1) * piece_length;
                 number += 1;

src/utils/http.rs

@@ -125,6 +125,6 @@ pub fn parse_range_header(range_header_value: &str, content_length: u64) -> Resu
     ))?;
 
     let start = valid_range.start().to_owned();
-    let length = valid_range.end() - start;
+    let length = valid_range.end() - start + 1;
     Ok(Range { start, length })
 }