Vue 3 中用组合式函数和 Shared Worker 实现后台分片上传（带哈希计算）

01. 背景

最近项目需求里有个文件上传功能，而客户需求里的文件基本上是比较大的，基本上得有 1 GiB 以上的大小，而上传大文件尤其是读大文件，可能会造成卡 UI 或者说点不动的问题。而用后台的 Worker 去实现是一个比较不错的解决办法。

02. 原理讲解

02.01. Shared Worker

Shared Worker 的好处是可以从几个浏览上下文中访问，例如几个窗口、iframe 或其他 worker。这样我们可以保证全局的页面上传任务都在我们的控制之下，甚至可以防止重复提交等功能。

02.02. 组合式函数

组合式函数的好处是在 Vue 3 是可以在任何 *.vue 文件中使用，并且是响应式方法，可以侦听 pinia 内 token 等的变化，传递给 Worker

02.03 简单流程设计

flowchart TB
id1[用户选择文件] --> id2[创建上传任务]
id2 --> id3[任务推送到 Worker]
id3 --> id4[上传到服务器]
id4 --> id5[Worker 返回任务状态]
id5 --> id6[组合式函数拦截状态放到 Map 里]

03. 代码

upload-worker.ts 代码

import { sha256 } from '@noble/hashes/sha256';
import { bytesToHex as toHex } from '@noble/hashes/utils';
interface SharedWorkerGlobalScope {
  onconnect: (event: MessageEvent<any>) => void;
}
const _self: SharedWorkerGlobalScope = self as any;
/**
 * 分片大小
 */
const pieceSize = 1024 * 1024;
/**
 * 消息参数
 */
interface MessageArg<T> {
  /**
   * 函数名
   */
  func: string;
  /**
   * 参数
   */
  arg: T;
}
/**
 * 上传任务信息
 */
interface UploadTaskInfo {
  /**
   * 文件名
   */
  fileName: string;
  /**
   * 上传路径
   */
  uploadPath: string;
  /**
   * 任务 id
   */
  id: string;
  /**
   * 文件大小
   */
  size: number;
  /**
   * 上传进度
   */
  progress: number;
  /**
   * 上传速度
   */
  speed?: number;
  /**
   * 任务状态
   */
  status: 'uploading' | 'paused' | 'canceled' | 'done' | 'error' | 'waiting';
  /**
   * 开始时间
   */
  startTime?: Date;
  /**
   * 结束时间
   */
  endTime?: Date;
  /**
   * 错误信息
   */
  errorMessage?: string;
}
/**
 * 上传任务
 */
interface UploadTask extends UploadTaskInfo {
  file: File;
  pieces: Array<boolean>;
  abort?: AbortController;
}
/**
 * 任务/哈希值映射
 */
const hashs = new Map();
/**
 * 上传任务列表
 */
const uploadTasks: Array<UploadTask> = [];
/**
 * 状态接收器
 */
const statusReceivers = new Map<string, MessagePort>();
/**
 * token 仓库
 */
const tokenStore = {
  /**
   * token
   */
  BearerToken: '',
};
/**
 * 返回上传状态
 * @param task 上传任务
 */
const updateStatus = (task: UploadTaskInfo) => {
  const taskInfo: UploadTaskInfo = {
    fileName: task.fileName,
    uploadPath: task.uploadPath,
    id: task.id,
    size: task.size,
    progress: task.progress,
    speed: task.speed,
    status: task.status,
    startTime: task.startTime,
    endTime: task.endTime,
    errorMessage: task.errorMessage,
  };
  statusReceivers.forEach((item) => {
    item.postMessage(taskInfo);
  });
};
/**
 * 运行上传任务
 * @param task 上传任务
 */
const runUpload = async (task: UploadTask) => {
  task.status = 'uploading';
  const hash = hashs.get(task.id) || sha256.create();
  hashs.set(task.id, hash);
  let retryCount = 0;
  const abort = new AbortController();
  task.abort = abort;
  while (task.status === 'uploading') {
    const startTime = Date.now();
    const index = task.pieces.findIndex((item) => !item);
    if (index === -1) {
      try {
        const response: { code: number; message: string } = await fetch(
          '/api/File/Upload',
          {
            method: 'PUT',
            headers: {
              Authorization: tokenStore.BearerToken,
              'Content-Type': 'application/json',
            },
            body: JSON.stringify({
              id: task.id,
              fileHash: toHex(hash.digest()),
              filePath: task.uploadPath,
            }),
          }
        ).then((res) => res.json());
        if (response.code !== 200) {
          throw new Error(response.message);
        }
        task.status = 'done';
        task.endTime = new Date();
        updateStatus(task);
      } catch (e: any) {
        task.status = 'error';
        task.errorMessage = e.toString();
        task.endTime = new Date();
        deleteUpload(task.id);
        updateStatus(task);
      }
      break;
    }
    const start = index * pieceSize;
    const end = start + pieceSize >= task.size ? task.size : start + pieceSize;
    const buffer = task.file.slice(index * pieceSize, end);
    hash.update(new Uint8Array(await buffer.arrayBuffer()));
    const form = new FormData();
    form.append('file', buffer);
    let isTimeout = false;
    try {
      const timer = setTimeout(() => {
        isTimeout = true;
        abort.abort();
      }, 8000);
      const response: { code: number; message: string } = await fetch(
        `/api/File/Upload?id=${task.id}&offset=${start}`,
        {
          method: 'POST',
          body: form,
          headers: {
            Authorization: tokenStore.BearerToken,
          },
          signal: abort.signal,
        }
      ).then((res) => res.json());
      clearTimeout(timer);
      if (response.code !== 200) {
        throw new Error(response.message);
      }
      task.pieces[index] = true;
      task.progress =
        task.pieces.filter((item) => item).length / task.pieces.length;
      task.speed = (pieceSize / (Date.now() - startTime)) * 1000;
      updateStatus(task);
    } catch (e: any) {
      retryCount++;
      if (retryCount > 3) {
        task.status = 'error';
        if (isTimeout) {
          task.errorMessage = 'UploadTimeout';
        } else {
          task.errorMessage = e.toString();
        }
        task.endTime = new Date();
        deleteUpload(task.id);
        updateStatus(task);
      }
    }
    runNextUpload();
  }
};
/**
 * 运行下一个上传任务
 */
const runNextUpload = async () => {
  if (uploadTasks.filter((item) => item.status === 'uploading').length > 3) {
    return;
  }
  const task = uploadTasks.find((item) => item.status === 'waiting');
  if (task) {
    await runUpload(task);
  }
};
/**
 * 排队上传
 * @param e 消息事件
 */
const queueUpload = async (
  e: MessageEvent<
    MessageArg<{
      id: string;
      file: File;
      uploadPath: string;
    }>
  >
) => {
  uploadTasks.push({
    file: e.data.arg.file,
    fileName: e.data.arg.file.name,
    id: e.data.arg.id,
    uploadPath: e.data.arg.uploadPath,
    size: e.data.arg.file.size,
    progress: 0,
    speed: 0,
    status: 'waiting',
    pieces: new Array(Math.ceil(e.data.arg.file.size / pieceSize)).fill(false),
    errorMessage: undefined,
  });
  updateStatus(uploadTasks[uploadTasks.length - 1]);
  await runNextUpload();
};
/**
 * 注册状态接收器
 * @param e 消息事件
 * @param sender 发送者
 */
const registerStatusReceiver = (
  e: MessageEvent<MessageArg<string>>,
  sender?: MessagePort
) => {
  if (sender) statusReceivers.set(e.data.arg, sender);
};
/**
 * 注销状态接收器
 * @param e 消息事件
 */
const unregisterStatusReceiver = (e: MessageEvent<MessageArg<string>>) => {
  statusReceivers.delete(e.data.arg);
};
/**
 * 更新 token
 * @param e 消息事件
 */
const updateToken = (e: MessageEvent<MessageArg<string>>) => {
  tokenStore.BearerToken = 'Bearer ' + e.data.arg;
};
/**
 * 暂停上传
 * @param e 消息事件
 */
const pauseUpload = (e: MessageEvent<MessageArg<string>>) => {
  const task = uploadTasks.find((item) => item.id === e.data.arg);
  if (task) {
    task.status = 'paused';
    if (task.abort) {
      task.abort.abort();
    }
    updateStatus(task);
  }
};
/**
 * 取消上传
 * @param e 消息事件
 */
const cancelUpload = (e: MessageEvent<MessageArg<string>>) => {
  const task = uploadTasks.find((item) => item.id === e.data.arg);
  if (task) {
    task.status = 'canceled';
    if (task.abort) {
      task.abort.abort();
    }
    deleteUpload(task.id);
    updateStatus(task);
  }
};
/**
 * 删除上传
 * @param id 任务 id
 */
const deleteUpload = async (id: string) => {
  uploadTasks.splice(
    uploadTasks.findIndex((item) => item.id === id),
    1
  );
  hashs.delete(id);
  await fetch(`/api/File/Upload?id=${id}`, {
    method: 'DELETE',
    headers: {
      Authorization: tokenStore.BearerToken,
    },
  }).then((res) => res.json());
};
/**
 * 消息路由
 */
const messageRoute = new Map<
  string,
  (e: MessageEvent<MessageArg<any>>, sender?: MessagePort) => void
>([
  ['queueUpload', queueUpload],
  ['registerStatusReceiver', registerStatusReceiver],
  ['updateToken', updateToken],
  ['pauseUpload', pauseUpload],
  ['cancelUpload', cancelUpload],
  ['unregisterStatusReceiver', unregisterStatusReceiver],
]);
// 监听连接
_self.onconnect = (e) => {
  const port = e.ports[0];
  port.onmessage = async (e) => {
    // 调用函数
    const func = messageRoute.get(e.data.func);
    if (func) {
      func(e, port);
    }
  };
  port.start();
};

upload-service.ts 代码

import UploadWorker from './upload-worker?sharedworker';
import { onUnmounted, ref, watch } from 'vue';
import { storeToRefs } from 'pinia';
import { useAuthStore } from 'src/stores/auth';
/**
 * 上传任务信息
 */
interface UploadTaskInfo {
  /**
   * 文件名
   */
  fileName: string;
  /**
   * 上传路径
   */
  uploadPath: string;
  /**
   * 任务 id
   */
  id: string;
  /**
   * 文件大小
   */
  size: number;
  /**
   * 上传进度
   */
  progress: number;
  /**
   * 上传速度
   */
  speed?: number;
  /**
   * 任务状态
   */
  status: 'uploading' | 'paused' | 'canceled' | 'done' | 'error' | 'waiting';
  /**
   * 开始时间
   */
  startTime?: Date;
  /**
   * 结束时间
   */
  endTime?: Date;
  /**
   * 错误信息
   */
  errorMessage?: string;
}
/**
 * 上传服务
 */
export const useUploadService = () => {
  const store = storeToRefs(useAuthStore());
  // 创建共享 worker
  const worker = new UploadWorker();
  /**
   * 上传任务列表
   */
  const uploadTasks = ref<Map<string, UploadTaskInfo>>(
    new Map<string, UploadTaskInfo>()
  );
  // 是否已注册状态接收器
  const isRegistered = ref(false);
  // 服务 id
  const serviceId = crypto.randomUUID();
  // 监听上传任务列表变化（只有在注册状态接收器后才会收到消息）
  worker.port.onmessage = (e: MessageEvent<UploadTaskInfo>) => {
    uploadTasks.value.set(e.data.id, e.data);
  };
  // 更新 token
  worker.port.postMessage({
    func: 'updateToken',
    arg: store.token.value,
  });
  watch(store.token, (token) => {
    worker.port.postMessage({
      func: 'updateToken',
      arg: token,
    });
  });
  /**
   * 排队上传
   * @param file 文件
   * @param uploadPath 上传路径
   */
  const queueUpload = (file: File, uploadPath: string) => {
    worker.port.postMessage({
      func: 'queueUpload',
      arg: {
        id: crypto.randomUUID(),
        file: file,
        uploadPath: uploadPath,
      },
    });
  };
  /**
   * 暂停上传
   * @param id 任务 id
   */
  const pauseUpload = (id: string) => {
    worker.port.postMessage({
      func: 'pauseUpload',
      arg: id,
    });
  };
  /**
   * 取消上传
   * @param id 任务 id
   */
  const cancelUpload = (id: string) => {
    worker.port.postMessage({
      func: 'cancelUpload',
      arg: id,
    });
  };
  /**
   * 注册状态接收器
   */
  const registerStatusReceiver = () => {
    worker.port.postMessage({
      func: 'registerStatusReceiver',
      arg: serviceId,
    });
    isRegistered.value = true;
  };
  /**
   * 注销状态接收器
   */
  const unregisterStatusReceiver = () => {
    worker.port.postMessage({
      func: 'unregisterStatusReceiver',
      arg: serviceId,
    });
    isRegistered.value = false;
  };
  onUnmounted(() => {
    unregisterStatusReceiver();
    worker.port.close();
  });
  return {
    uploadTasks,
    queueUpload,
    pauseUpload,
    cancelUpload,
    registerStatusReceiver,
    unregisterStatusReceiver,
  };
};

04. 用法

// 引入组合式函数
const uploadService = useUploadService();
// 注册状态接收器
uploadService.registerStatusReceiver();
// 表单绑定上传方法
const upload = (file: File, filePath: string) => {
  uploadService.queueUpload(file, filePath);
}
// 监听上传进度，当然也可以直接展示在界面，毕竟是 Ref
watch(uploadService.uploadTasks, console.log);