vue el-upload 上传到oss服务器

可以使用第三方库 `ali-oss` 来完成该功能。具体操作可以参考以下示例代码：

<template>
  <el-upload
    action=""
    :before-upload="beforeUpload"
    :on-success="onSuccess"
    :on-error="onError"
    :headers="{ 'x-oss-security-token': ossToken }"
    :data="{ key: uploadedKey }"
    :file-list="fileList"
    multiple>
    <el-button size="small" type="primary">上传文件</el-button>
  </el-upload>
</template>

<script>
import OSS from 'ali-oss';

export default {
  data() {
    return {
      fileList: [],
      uploadedKey: '',
      ossToken: '',
    };
  },
  methods: {
    async beforeUpload(file) {
      // 获取 OSS Token 
      const response = await this.$http.get('https://example.com/get-oss-token');
      if (response.data.code !== 0) {
        this.$message.error('获取 OSS Token 失败');
        return false;
      }
      this.ossToken = response.data.data;
      
      // 构造上传参数
      const client = new OSS({
        region: 'oss-cn-hangzhou', // OSS Bucket 所在地域
        accessKeyId: 'your-access-key-id',
        accessKeySecret: 'your-access-key-secret',
        stsToken: this.ossToken,
        bucket: 'your-bucket-name',
      });
      const key = `uploads/${file.name}`;
      this.uploadedKey = key;
      const info = await client.multipartUpload(key, file, {
        progress: (p) => {
          console.log(`Progress: ${p}`);
        },
        meta: {
          year: '2022'
        }
      });
    },
    onSuccess(response, file, fileList) {
      this.$message.success('文件上传成功');
    },
    onError(error, response, file) {
      this.$message.error('文件上传失败');
    },
  }
};
</script>

注意：上传过程中需要先获取阿里云的 OSS Token，并且在请求头中加上 `x-oss-security-token` 参数，同时需要设置 OSS 上传参数：Access Key ID，Access Key Secret，STS Token 和 Bucket Name。