fix: 修复文件无法直接下载问题

Closes continew/continew-admin#IBF2YB

src/utils/downloadFile.ts

@@ -25,8 +25,9 @@ export function downloadByUrl({
 }): Promise<boolean> {
   // 是否同源
   const isSameHost = new URL(url).host === location.host
-  return new Promise<boolean>((resolve) => {
+  return new Promise<boolean>((resolve, reject) => {
     if (isSameHost) {
+      // 同源资源，直接使用 <a> 标签下载
       const link = document.createElement('a')
       link.href = url
       link.target = target
@@ -49,36 +50,23 @@ export function downloadByUrl({
       window.open(url, target)
       return resolve(true)
     } else {
-      const elink = document.createElement('a')
-      elink.href = url
-      elink.target = '_self'
-      elink.download = fileName as string
-      elink.style.display = 'none'
-      document.body.appendChild(elink)
-      elink.click()
-      document.body.removeChild(elink)
-      // const canvas = document.createElement('canvas')
-      // const img = document.createElement('img')
-      // img.setAttribute('crossOrigin', 'Anonymous')
-      // img.src = url
-      // img.onload = () => {
-      //   canvas.width = img.width
-      //   canvas.height = img.height
-      //   const context = canvas.getContext('2d')!
-      //   context.drawImage(img, 0, 0, img.width, img.height)
-      //   // window.navigator.msSaveBlob(canvas.msToBlob(),'image.jpg');
-      //   // saveAs(imageDataUrl, '附件');
-      //   canvas.toBlob((blob) => {
-      //     const link = document.createElement('a')
-      //     if (!blob) return
-      //     link.href = window.URL.createObjectURL(blob)
-      //     link.download =  fileName || getFileName(url)
-      //     link.click()
-      //     URL.revokeObjectURL(link.href)
-      //     resolve(true)
-      //   }, 'image/jpeg')
-      // }
-      // img.onerror = (e) => reject(e)
+      // 跨域资源，使用 fetch 获取文件并下载
+      fetch(url)
+        .then((response) => response.blob())
+        .then((blob) => {
+          const link = document.createElement('a')
+          link.href = URL.createObjectURL(blob)
+          link.download = fileName || getFileName(url)
+          link.style.display = 'none'
+          document.body.appendChild(link)
+          link.click()
+          document.body.removeChild(link)
+          URL.revokeObjectURL(link.href)
+          resolve(true)
+        })
+        .catch((err) => {
+          reject(err)
+        })
     }
   })
 }