feat: 添加preview路由用于文件预览

- preview路由预览文件
- FilePreviewer组件
- 删除Document卡片的下载按钮，使用单独的页面用于文件下载
- preview布局

app/components/DocumentList.vue

@@ -16,13 +16,6 @@
             >格式:
             {{ formatFileExtension(getFileExtension(doc.filename)) }}</span
           >
-          <el-button
-            class="download-button"
-            type="primary"
-            @click="handleDownload(doc.title, doc.url)"
-          >
-            下载
-          </el-button>
         </div>
       </div>
     </el-card>

app/components/FilePreviewer.vue

@@ -0,0 +1,177 @@
+<template>
+  <section class="h-screen flex flex-col">
+    <!-- 头部工具栏 -->
+    <header
+      v-if="showToolbar && fileMeta"
+      class="p-3 border-b flex items-center justify-between"
+    >
+      <div class="min-w-0">
+        <h2 class="truncate font-medium" :title="fileMeta.filename_download">
+          {{ fileMeta.filename_download }}
+        </h2>
+        <p class="text-xs text-gray-500">
+          {{ fileMeta.type }} · {{ formatedSize }} · {{ formatedDate }}
+        </p>
+      </div>
+
+      <div class="shrink-0 flex items-center gap-2">
+        <button
+          class="px-3 py-1.5 rounded border hover:bg-gray-50"
+          type="button"
+          :disabled="!fileMeta"
+          @click="openInNewTab"
+        >
+          在新标签打开
+        </button>
+        <button
+          class="px-3 py-1.5 rounded bg-blue-600 text-white hover:bg-blue-700 disabled:opacity-50"
+          type="button"
+          :disabled="!fileMeta"
+          @click="download"
+        >
+          下载
+        </button>
+      </div>
+    </header>
+
+    <div class="flex-1 overflow-hidden">
+      <!-- 加载状态 -->
+      <div v-if="pending" class="h-48 grid place-items-center border rounded">
+        正在加载...
+      </div>
+      <div
+        v-else-if="errorText"
+        class="h-48 grid place-items-center border rounded text-red-600"
+      >
+        {{ errorText }}
+      </div>
+      <!-- 文件预览 -->
+      <ClientOnly v-else>
+        <div
+          v-if="fileMeta && previewable"
+          class="h-full w-full flex justify-center bg-gray-50"
+        >
+          <!-- 图片 -->
+          <el-image
+            v-if="isImage"
+            fit="contain"
+            class="max-w-full max-h-full select-none"
+            :src="src"
+            :alt="fileMeta.title || fileMeta.filename_download"
+          />
+
+          <!-- PDF -->
+          <iframe
+            v-else-if="isPdf"
+            :src="src"
+            title="PDF 预览"
+            class="w-full h-full border-0"
+          />
+
+          <!-- 视频 -->
+          <video
+            v-else-if="isVideo"
+            :src="src"
+            controls
+            class="w-full bg-black"
+          />
+
+          <!-- 文本（简单方式用 iframe；如需代码高亮可改为拉取文本并渲染 <pre>） -->
+          <iframe
+            v-else-if="isText"
+            :src="src"
+            title="文本预览"
+            class="w-full h-full border-0"
+          />
+        </div>
+      </ClientOnly>
+    </div>
+  </section>
+</template>
+
+<script setup lang="ts">
+  const props = withDefaults(
+    defineProps<{
+      /** 预览的文件 ID */
+      fileId?: string;
+      file?: FileMeta;
+
+      /** 是否显示上方工具栏（文件名、大小、按钮） */
+      showToolbar?: boolean;
+
+      /** 下载 API 基础路径（你的后端流接口），用于“下载”按钮 */
+      downloadApiBase?: string;
+
+      /** 追加到 file.url 的查询（如临时 token），形如 { token: 'xxx' } */
+      extraQuery?: Record<string, string | number | boolean>;
+    }>(),
+    {
+      fileId: undefined,
+      file: undefined,
+      showToolbar: true,
+      downloadApiBase: '/api/download',
+      extraQuery: undefined,
+    }
+  );
+
+  const { data, pending, error } = await useFetch<FileMeta>(
+    () => (props.file ? null : `/api/file/${props.fileId}`),
+    { server: true }
+  );
+
+  const errorText = computed(() => error.value?.message ?? null);
+  const fileMeta = computed(() => props.file ?? data.value ?? null);
+
+  /** 预览源地址：支持在 file.url 上追加额外 query（如临时 token、inline） */
+  const src = computed<string>(() => {
+    if (!fileMeta.value) return '';
+    const url = new URL(fileMeta.value.url, window?.location?.origin);
+    if (props.extraQuery) {
+      Object.entries(props.extraQuery).forEach(([k, v]) =>
+        url.searchParams.set(k, String(v))
+      );
+    }
+    return url.toString();
+  });
+
+  /** 类型判定 */
+  const isImage = computed(
+    () => fileMeta.value?.type.startsWith('image/') === true
+  );
+  const isPdf = computed(() => fileMeta.value?.type === 'application/pdf');
+  const isVideo = computed(
+    () => fileMeta.value?.type.startsWith('video/') === true
+  );
+  const isText = computed(
+    () => fileMeta.value?.type.startsWith('text/') === true
+  );
+  const previewable = computed(() => fileMeta.value?.previewable === true);
+
+  const formatedSize = computed(() => {
+    const size = fileMeta.value?.filesize ?? 0;
+    return formatFileSize(size);
+  });
+
+  const formatedDate = computed(() => {
+    if (!fileMeta.value?.uploaded_on) return '';
+    return new Date(fileMeta.value.uploaded_on).toLocaleDateString();
+  });
+
+  /** 下载动作：走你自己的流式后端，避免直链暴露（便于权限与统计） */
+  function download(): void {
+    if (!fileMeta.value) return;
+    const id = fileMeta.value.id;
+    const a = document.createElement('a');
+    a.href = `${props.downloadApiBase}/${encodeURIComponent(id)}`;
+    a.download = fileMeta.value.filename_download;
+    document.body.appendChild(a);
+    a.click();
+    document.body.removeChild(a);
+  }
+
+  /** 新标签打开（直接访问直链，适合预览失败时的兜底体验） */
+  function openInNewTab(): void {
+    if (!src.value) return;
+    window.open(src.value, '_blank', 'noopener,noreferrer');
+  }
+</script>

app/layouts/preview.vue

@@ -0,0 +1,5 @@
+<template>
+  <div>
+    <slot />
+  </div>
+</template>

app/pages/preview/[id].vue

@@ -0,0 +1,13 @@
+<template>
+  <file-previewer :file-id="id" />
+</template>
+
+<script setup lang="ts">
+  definePageMeta({
+    layout: 'preview',
+  });
+
+  const route = useRoute();
+
+  const id = computed(() => route.params.id as string);
+</script>