细节调整及优化（26.8.3）

src-tauri/src/download_engine/http_dl.rs

@@ -21,15 +21,35 @@ const READ_STALL_TIMEOUT: std::time::Duration = std::time::Duration::from_secs(3
 /// HTTP/HTTPS 下载器
 #[derive(Clone)]
 pub struct HttpDownloader {
-    client: Client,
+    /// 默认客户端：尊重系统代理（reqwest 默认行为，mihomo 开启系统代理时经其转发）
+    system_client: Client,
+    /// 直连客户端：强制禁用系统代理（no_proxy）
+    direct_client: Client,
 }
 
 impl HttpDownloader {
     pub fn new() -> Self {
-        let client = Client::builder()
+        let system_client = Client::builder()
             .build()
             .unwrap_or_else(|_| Client::new());
-        Self { client }
+        let direct_client = Client::builder()
+            // 强制直连：即使系统代理已开启，下载也不经过代理
+            .no_proxy()
+            .build()
+            .unwrap_or_else(|_| Client::new());
+        Self {
+            system_client,
+            direct_client,
+        }
+    }
+
+    /// 根据 use_proxy 选择客户端
+    fn client(&self, use_proxy: bool) -> &Client {
+        if use_proxy {
+            &self.system_client
+        } else {
+            &self.direct_client
+        }
     }
 
     /// 探测下载资源信息（大小、是否支持 Range、文件名）
@@ -38,10 +58,11 @@ impl HttpDownloader {
         &self,
         url: &str,
         headers: &HashMap<String, String>,
+        use_proxy: bool,
     ) -> Result<ProbeResult, String> {
+        let client = self.client(use_proxy);
         // 先尝试 Range 请求（能同时判断 Accept-Ranges 和获取大小）
-        let mut req = self
-            .client
+        let mut req = client
             .get(url)
             .header("Range", "bytes=0-0")
             .header("User-Agent", "Thing-Download-Engine/1.0");
@@ -97,7 +118,7 @@ impl HttpDownloader {
             }
             Err(_) => {
                 // GET 失败，尝试 HEAD 作为回退
-                let mut head_req = self.client.head(url);
+                let mut head_req = client.head(url);
                 for (k, v) in headers {
                     head_req = head_req.header(k, v);
                 }
@@ -132,6 +153,7 @@ impl HttpDownloader {
     /// - `cancel`: 取消标志
     /// - `progress`: 每个分段的已下载字节（AtomicU64，与 segments 一一对应）
     /// - `limiter`: 全局限速器
+    /// - `use_proxy`: 是否使用系统代理（false=强制直连）
     pub async fn download(
         &self,
         url: &str,
@@ -141,7 +163,9 @@ impl HttpDownloader {
         cancel: Arc<AtomicBool>,
         progress: &[Arc<AtomicU64>],
         limiter: Arc<RateLimiter>,
+        use_proxy: bool,
     ) -> Result<(), String> {
+        let client = self.client(use_proxy);
         let total_size = segments.iter().map(|s| s.len()).sum();
 
         // 预分配文件（若已知大小）
@@ -167,7 +191,7 @@ impl HttpDownloader {
             // 单线程下载（不支持 Range 或文件太小）
             let seg = &segments[0];
             let prog = &progress[0];
-            self.download_segment(url, headers, seg, file_path, cancel.clone(), prog.clone(), limiter)
+            self.download_segment(url, headers, seg, file_path, cancel.clone(), prog.clone(), limiter, client)
                 .await?;
             return Ok(());
         }
@@ -187,7 +211,7 @@ impl HttpDownloader {
                 .unwrap_or_default();
             let limiter = limiter.clone();
             let file_path = file_path.to_path_buf();
-            let client = self.client.clone();
+            let client = client.clone();
 
             join_set.spawn(async move {
                 download_segment_with_client(
@@ -241,9 +265,10 @@ impl HttpDownloader {
         cancel: Arc<AtomicBool>,
         progress: Arc<AtomicU64>,
         limiter: Arc<RateLimiter>,
+        client: &Client,
     ) -> Result<(), String> {
         download_segment_with_client(
-            &self.client,
+            client,
             url,
             headers,
             seg,
@@ -366,6 +391,15 @@ async fn download_segment_with_client(
                     limiter.consume(buf.len() as u64).await;
                     buf.clear();
                 }
+                // 校验：已知大小的分段若流提前结束（收到的字节数不足分段长度），
+                // 说明服务器提前断开或返回不完整内容，不能标记为完成，否则文件会被截断
+                if !unknown_size && local_completed < seg.len() {
+                    return Err(format!(
+                        "文件不完整：已接收 {} / {} 字节，服务器提前结束连接",
+                        local_completed,
+                        seg.len()
+                    ));
+                }
                 break;
             }
             Err(_) => {