拖拽上传文件

<template>
  <div ref="drag" class="drag">
    <div class="drag-icon-box">
      <!-- 采用的是 element-ui 的图标 -->
      <i class="el-icon-upload"></i> 
    </div>
    <div class="drag-message">
      <span class="drag-message-title">将文件拖动到此处，或</span>
      <label for="file" class="drag-message-label">
        <input
          class="drag-message-input"
          type="file"
          id="file"
          name="file"
          @change="handleFileChange"
        />
        <span class="drag-message-manual">点击上传</span>
      </label>
    </div>
    <div>
  <!-- 采用的是 element-ui 的进度条组件 -->
      <el-progress
        :stroke-width="20"
        :text-inside="true"
        :percentage="uploadProgress"
      ></el-progress>
    </div>
  </div>
</template>

<script>
export default {
  data() {
    return {
      file: null,
      upLoadProgress:0//进度条
    }
  },
  async mounted() {
    // 给容器绑定相关的拖拽事件
    this.bindEvents()
  },
  methods: {
    bindEvents() {
      const drag = this.$refs.drag
      // 被拖动的对象进入目标容器
      drag.addEventListener('dragover', e => {
        e.preventDefault()
        drag.style.borderColor = 'red'
      })
      // 被拖动的对象离开目标容器
      drag.addEventListener('dragleave', e => {
        e.preventDefault()
        drag.style.borderColor = '#eee'
      })
      // 被拖动的对象进入目标容器，释放鼠标键
      drag.addEventListener('drop', e => {
        e.preventDefault()
        drag.style.borderColor = '#eee'
        const fileList = e.dataTransfer.files
        this.file = fileList[0]
        this.uploadFile()
      })
    },
      
    async uploadFile() {
      const form = new FormData()
      form.append('name', 'file')
      form.append('file', this.file)
      const res = await axios.post('/upload', form，{
              //axios中onUploadProcess实现
            onUploadProgress: progress => {
              this.uploadProgress = Number(
                ((progress.loaded / progress.total) * 100).toFixed(2)
              )
            }
      })
    },
      
    handleFileChange(e) {
      const file = e.target.files[0]
      if (!file) return
      this.file = file
      this.uploadFile()
    }
  }
}
</script>

<style lang="scss" scoped>
.drag {
  width: 660px;
  height: 300px;
  border: 2px dashed;
  border-color: #a3a3a3;
  border-radius: 5px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
  .drag-icon-box {
    width: 100%;
    height: 60px;
    text-align: center;
    font-size: 50px;
    line-height: 60px;
    color: #606266;
  }
  .drag-message {
    width: 100%;
    height: 50px;
    line-height: 50px;
    text-align: center;
    .drag-message-title {
      font-size: 14px;
      color: #606266;
    }
    .drag-message-label {
      width: 120px;
      height: 50px;
      height: auto;
      position: relative;
      overflow: hidden;
      .drag-message-input {
        position: absolute;
        left: -100px;
        top: -100px;
        z-index: -1;
        display: none;
      }
      .drag-message-manual {
        font-size: 14px;
        color: #4b87ff;
        cursor: pointer;
      }
    }
  }
}
</style>

取消上传事件

利用axios的cancel token进行取消

1. 使用CancelToken工厂方法创建cancel token

   const CancelToken = axios.CancelToken;
   const source = CancelToken.source();
   
   axios.post('/upload', form, {
     cancelToken: source.token
   })
   
   source.cancel();
   

2. 传递一个executor函数到CancelToken的构造函数来创建cancel token

   const CancelToken = axios.CancelToken;
   let cancel;
   
   axios.post('/upload', form, {
     cancelToken: new CancelToken(function executor(c) {
       cancel = c;
     })
   });
   
   cancel();