关于javascript:分片上传方案

一、index.ts

import Embitter from "../tools/emmitter";
import Slice from "./sliceUpload";

// 上传状态
const statusMap = {
  fail: 0, // 失败
  success: 1, // 胜利
  inProcessing: 2, // 进行中
  paused: 3, // 暂停
  canceled: 4, // 已勾销
  wait: 5 // 未开始
};

interface IConfig {
  file: File;
  parallel: number;
  partSize: number;
}

class Client extends Embitter {
  private file: File;
  private parallel: number; // 分片并行数量
  private partSize: number; // 分片大小

  private status: number; // 0 失败 1 胜利 2 进行中 3 暂停 4 勾销 5 未开始 6 报错
  private partInfo: IPartInfo;
  private partsArray: Slice[]; // 保护所有分片
  private sliceUploadSuccess: Set<number>; // 上传胜利的分片 partIndex
  private sliceUploadRunning: Set<number>; // 上传中的分片 partIndex
  private sliceEvent: Embitter;

  constructor(config: IConfig) {super();
    this.file = config.file;
    this.parallel = config.parallel || defaultParallel;
    this.partInfo = {
      partSize: config.partSize,
      partNum: Math.ceil(config.file.size / config.partSize),
    };
    this.status = statusMap.wait; // 默认未开始

    this.partsArray = [];
    // 记录胜利的分片上传
    this.sliceUploadSuccess = new Set([]);
    // 记录上传中的分片
    this.sliceUploadRunning = new Set([]);
    // 监听分片上传
    this.sliceEvent = new Embitter();}

  getConfig() {
    return {
      file: this.file,
      partInfo: this.partInfo,
      sliceEvent: this.sliceEvent,
      status: this.status,
    };
  }

  private startUploadAllSlice() {this.sliceEvent.on("success", (partIndex: number) => {if (!this.sliceUploadSuccess.has(partIndex)) {this.sliceUploadSuccess.add(partIndex);

        this.sliceUploadRunning.delete(partIndex);

        const progress = this.sliceUploadSuccess.size / this.partInfo.partNum;

        this.emmit("progress", progress);

        if (progress >= 1) {this.endSliceUpload();
        } else {this._resumeUpload();
        }
      }
    });

    this.sliceEvent.on("error", (partIndex: number, err: any) => {this.emmit("error", err);

      this.sliceUploadRunning.delete(partIndex);

      this.status = statusMap.paused; // 上传出现异常就先暂停上传

      this.emmit("pause");
    });

    const that = this;

    // 创立分片上传实例
    this.partsArray = Array.from(new Array(this.partInfo.partNum),
      (x, i) =>
        new Slice({
          client: that,
          partIndex: i + 1,
        })
    );

    // 开始分片上传
    this._resumeUpload();}

  /**
   * 上传文件：开始上传或者复原上传
   * @param file
   * @returns {Promise<void>}
   */
  private async uploadFile(): Promise<void> {if (this.status !== statusMap.inProcessing) {
      this.status = statusMap.inProcessing;
      this.emmit("start");
    }
    // 开始上传
    this.startUploadAllSlice();}

  /**
   * 开始上传
   * @param file
   * @returns {Promise<void>}
   */
  public async startUpload(): Promise<void> {if (this.status !== statusMap.wait) {console.log("startUpload status error", this.status);
      this.emmit("error", errorMap.hasStarted);
      return;
    }

    this.uploadFile();}

  // 完结分片上传事务
  private async endSliceUpload() {if (statusMap.canceled === this.status) {return;}
    const tagList = [];
    for (const val of this.partsArray) {
      tagList.push({
        partIndex: val.partIndex,
        partTag: val.partTag,
      });
    }

    // 完结分片上传事务
    const res = await action.endMultipartUpload({tagList});

    if (!res.hasOwnProperty("err")) {
      this.status = statusMap.success;
      this.emmit("success", {
        resourceId: res.resourceId,
        preResourceId: res.preResourceId,
        url: res.path,
      });
    }
  }

  /**
   * 暂停上传
   * @returns {Promise<void>}
   */
  public async pauseUpload() {
    // 只有文件正在上传中，才能够暂停
    if (this.status !== statusMap.inProcessing) {this.emmit("error", errorMap.noInProcess);
      return;
    }

    this.status = statusMap.paused;
    this.emmit("pause");
  }

  /**
   * 分片上传开始
   * @returns
   */
  private _resumeUpload() {
    const todoParts = this.partsArray.filter((part) =>
        !this.sliceUploadSuccess.has(part.partIndex) &&
        !this.sliceUploadRunning.has(part.partIndex)
    );
    let job;
    while (
      this.sliceUploadRunning.size < this.parallel &&
      ![statusMap.paused, statusMap.canceled].includes(this.status) &&
      (job = todoParts.shift())
    ) {this.sliceUploadRunning.add(job.partIndex);
      job.startUpload();}
  }

  /**
   * 复原上传
   * @returns {Promise<void>}
   */
  public async resumeUpload() {if (this.status !== statusMap.paused) {this.emmit("error", errorMap.noCanResume);
      return;
    }
    this.status = statusMap.inProcessing;
    this.emmit("start");
    this._resumeUpload();}

  /**
   * 破除上传
   * @returns {Promise<void>}
   */
  public async abortUpload(): Promise<void> {
    // 只有文件正在上传中或者上传曾经暂停，才能够勾销上传
    if (
      this.status !== statusMap.inProcessing &&
      this.status !== statusMap.paused
    ) {this.emmit("error", errorMap.noCanCancel);
      return;
    }
    const result = await action.abortUpload();
    // 勾销上传胜利
    if (!result.err) {
      this.status = statusMap.canceled;
      this.emmit("abort");
      this.emmit("progress", 0);
      return;
    }

    this.emmit("error", result.err);
  }
}

export default Client;

二、sliceUpload.ts

import {generateMD5} from "../tools/utils";
import action from "../action";
import Client from "./index";
class Slice {
  // 以下是独有属性
  private sliceFile: Blob;
  private md5Content: string;
  private signatureUrl: string;
  private _status: number; // 0 失败 1 胜利 2 进行中 3 暂停 4 勾销 5 未开始 6 报错
  private _partTag: string; // 上传胜利会有标签
  private _partIndex: number;
  private client: Client; // 上传实例

  constructor(config: ISliceConfig) {
    this.client = config.client;
    this._partIndex = config.partIndex;

    this._status = statusMap.wait;
    this._partTag = "";
  }

  get partTag() {return this._partTag;}

  get status() {return this._status;}

  get partIndex() {return this._partIndex;}

  /**
   * 获取分片签名上传 url
   */
  private async getSignatureUrl() {const { file, sliceEvent} = this.client.getConfig();

    const res = await action.getMultipartUrl(this._partIndex, {
      headers: {
        "FileContent-MD5": this.md5Content,
        "FileContent-Type": file.type || "application/octet-stream",
      },
    });
    if (!res.err) {this.signatureUrl = res.signatureUrl;} else {if (this.getCurrentStatus() === statusMap.canceled) {return;}
      this._status = statusMap.fail;
      sliceEvent.emmit("error", this.partIndex, res.err);
    }
  }

  private generateSliceFile() {const { partInfo, file} = this.client.getConfig();
    const start = (this._partIndex - 1) * partInfo.partSize;
    let end = start + partInfo.partSize;
    if (this._partIndex === partInfo.partNum) {end = file.size;}
    this.sliceFile = file.slice(start, end);
  }

  private isContinueUpload() {const status = this.getCurrentStatus();
    return ![statusMap.canceled, statusMap.paused].includes(status);
  }

  private getCurrentStatus() {const { status} = this.client.getConfig();
    return status;
  }

  private async uploadSlice() {const { file, sliceEvent} = this.client.getConfig();

    const res = await action.startPartUpload(
      this.signatureUrl,
      this.sliceFile,
      {
        headers: {
          "Content-MD5": this.md5Content,
          "Content-Type": file.type || "application/octet-stream",
        },
      }
    );

    if (!res.err) {
      this._status = statusMap.success;
      try {this._partTag = JSON.parse(res.headers.etag);
      } catch (error) {this._partTag = res.headers.etag;}

      sliceEvent.emmit("success", this._partIndex);
    } else {if (this.getCurrentStatus() === statusMap.canceled) {return;}
      this._status = statusMap.fail;
      sliceEvent.emmit("error", this._partIndex, res.err);
    }
  }

  // 上传分片入口
  async startUpload() {if (this.isContinueUpload() && !this.sliceFile) {this.generateSliceFile();
    }

    if (this.isContinueUpload() && !this.md5Content && this.sliceFile) {this.md5Content = await generateMD5(this.sliceFile);
    }

    if (this.isContinueUpload() && !this.signatureUrl && this.md5Content) {await this.getSignatureUrl();
    }

    if (this.isContinueUpload() && this.signatureUrl) {await this.uploadSlice();
    }

    return this._status === statusMap.success;
  }
}

export default Slice;

三、demo 集成

import xyUpload from "./index.ts";

const client = new xyUpload({
  file,
  parallel: 3,
  partSize: 2000000,
});

client.on("progress", (res) => {console.log("progress", res);
});

client.on("success", (res) => {resolve(res);
});

client.on("error", (res) => {reject(res);
});

client.on("start", () => {console.log("开始了");
});
// 开始上传
client.startUpload();

// 暂停上传
client.pauseUpload();

// 持续上传
client.resumeUpload();

// 破除上传
client.abortUpload();