上传下载

src/utils/index.js

@@ -183,4 +183,47 @@ export function fileDown (downLoadUrl, fileName, id,data) {
 //   console.log("fileDownloadCallback  下载文件  回调    " + JSON.stringify(obj));
 // }
 
+/**
+ * 通过 POST 接口下载图片并返回 blob URL
+ * @param {string} attach_id 文件ID
+ * @returns {Promise<string>} blob URL
+ */
+export async function getImageBlobUrl(attach_id) {
+  try {
+    const { downloadFile } = await import('@/api/api')
+    const blob = await downloadFile(attach_id)
+    if (blob instanceof Blob && blob.size > 0) {
+      const type = blob.type && blob.type.startsWith('image/') ? blob.type : 'image/jpeg'
+      const imgBlob = new Blob([blob], { type })
+      const url = URL.createObjectURL(imgBlob)
+      console.log('getImageBlobUrl ok: id=', attach_id, 'type=', blob.type, 'size=', blob.size, 'url=', url)
+      return url
+    }
+    console.error('getImageBlobUrl 无效响应: id=', attach_id, 'isBlob=', blob instanceof Blob, 'size=', blob && blob.size, 'type=', blob && blob.type)
+    return ''
+  } catch (e) {
+    console.error('getImageBlobUrl 请求失败: id=', attach_id, e)
+    return ''
+  }
+}
+/**
+ * 通过 POST 接口下载文件并触发浏览器保存
+ * 注意:后端返回的是文件流(Blob),浏览器不会自动下载,需手动触发
+ * @param {string} attachId 文件ID
+ * @param {string} [fileName] 保存的文件名(带后缀),缺省为 'download'
+ */
+export async function downloadFileById(attachId, fileName) {
+  const { downloadFile } = await import('@/api/api')
+  const blob = await downloadFile(attachId)
+  if (!(blob instanceof Blob)) return
+  const url = URL.createObjectURL(blob)
+  const a = document.createElement('a')
+  a.href = url
+  a.download = fileName || 'download'
+  document.body.appendChild(a)
+  a.click()
+  a.remove()
+  URL.revokeObjectURL(url)
+}
+
 export default service