info_admin/app/service/imageHandleService.js

'use strict';

const fs = require('fs');
// node.js 路径操作对象
const path = require('path');
//  异步二进制 写入流
const awaitWriteStream = require('await-stream-ready').write;
// 管道读入一个虫洞。
const sendToWormhole = require('stream-wormhole');

const Service = require('egg').Service;
class ImageHandleService extends Service {

  async upload(filename) {
    const ctx = this.ctx;
    let stream;
    try {
      stream = await ctx.getFileStream();// 获取文件
      if (!filename) {
        // 新建一个文件名 = 文件名 + 时间 + 文件后缀
        filename = path.parse(stream.filename).name
          + Date.now() + path.extname(stream.filename)
          .toLocaleLowerCase();
      }
      // 文件生成绝对路径
      const target = path
        .join(this.app.config.defaultUploadPath, filename);
      // 生成一个文件写入 文件流
      const writeStream = fs.createWriteStream(target);
      // 异步把文件流 写入
      await awaitWriteStream(stream.pipe(writeStream));
      return this.app.config.defaultWritePathPre + filename;
    } catch (err) {
      ctx.logger.debug(err);
      // 如果出现错误，关闭管道
      await sendToWormhole(stream);
      return null;
    }

  }
}
module.exports = ImageHandleService;