vue合家福实例(6)：文件上传组件自定义ajax请求

element-ui提供了文件上传的组件，官方文档。官方文档还是比较详细的。这里是一点实际应用。这里用了头像上传和照片墙

官方示例

效果

<script>
export default {
  name: 'AdminComponentsUpload',
  data () {
    return {
      imageUrl: ''
    }
  },
  created () {},
  methods: {
    beforeAvatarUpload (file) {
      const isJPG = file.type === 'image/jpeg'
      const isLt2M = file.size / 1024 / 1024 < 2
      if (!isJPG) {
        this.$message.error('上传头像图片只能是 JPG 格式!')
      }
      if (!isLt2M) {
        this.$message.error('上传头像图片大小不能超过 2MB!')
      }
      return isJPG && isLt2M
    },
    handleAvatarSuccess (res, file) {
      this.imageUrl = URL.createObjectURL(file.raw)
    },
    handleRemove (file, fileList) {
      console.log(file, fileList)
    },
    handlePictureCardPreview (file) {
      console.log(file)
    }
  }
}
</script>

<template>
  <el-main>
    <el-scrollbar class="default-scrollbar" wrap-class="default-scrollbar__wrap" view-class="p20-scrollbar__view">
      <h2 class="title">用户头像上传</h2>
      <div class="avater-wrap">
        <el-upload
          class="avatar-uploader"
          action="https://jsonplaceholder.typicode.com/posts/"
          :show-file-list="false"
          :on-success="handleAvatarSuccess"
          :before-upload="beforeAvatarUpload">
          <img v-if="imageUrl" :src="imageUrl" class="avatar">
          <i v-else class="el-icon-plus avatar-uploader-icon"></i>
        </el-upload>
      </div>
      <h2 class="title">照片墙</h2>
      <div class="wall-wrap">
        <el-upload
          action="https://jsonplaceholder.typicode.com/posts/"
          list-type="picture-card"
          :on-preview="handlePictureCardPreview"
          :on-remove="handleRemove">
          <i class="el-icon-plus"></i>
        </el-upload>
      </div>
    </el-scrollbar>
  </el-main>
</template>

<!-- Add "scoped" attribute to limit CSS to this component only -->
<style scoped>
.title {
  line-height: 60px;
}
.avater-wrap {
  width: 180px;
  height: 180px;
}
.avatar-uploader {
  border: 1px dashed #d9d9d9;
  border-radius: 6px;
  cursor: pointer;
  position: relative;
  overflow: hidden;
}
.avatar-uploader:hover {
  border-color: #409EFF;
}
.avatar-uploader-icon {
  font-size: 28px;
  color: #8c939d;
  width: 178px;
  height: 178px;
  line-height: 178px;
  text-align: center;
}
.avatar {
  width: 178px;
  height: 178px;
  display: block;
}
</style>

第一个问题：上传图片的时候跨域错误。这个问题就不在这里解决了，实际项目中不会用这个地址上传。
第二个问题：换成自己的服务器地址，vue项目中我用的是axios进行ajax请求。所有的ajax都在/src/request中统一管理。还有服务器的接口是要带access_token才允许访问上传图片的接口的。
假如我的上传请求如下：

// IMAGE api
import Service from '../base'
export default {
  uploadImage (file, handleProgress) {
    const formData = new FormData()
    formData.append('file', file)
    return Service.post('/zuul/image/upload', formData, {
      progress (e) {
        if (e.total > 0) {
          e.percent = e.loaded / e.total * 100
        }
        if (handleProgress) {
          handleProgress(e)
        }
      },
      onUploadProgress (e) {
        if (e.total > 0) {
          e.percent = e.loaded / e.total * 100
        }
        if (handleProgress) {
          handleProgress(e)
        }
      }
    })
  }
}

access_token在base中统一处理。这样就要修改组件的参数了。

action的值改成'upload'，不使用组件的这个参数上传文件；
增加参数:http-request="handleUploadImage"。用自己的方法进行上传。这个回调函数中实现上传业务；
实现handleUploadImage函数

    handleUploadImage (options) {
      return new Promise((resolve, reject) => {
        FileService.uploadImage(options.file, options.onProgress).then(res => {
          resolve(res)
        }).catch(error => {
          this.$message.error(error || '上传图片失败!')
        })
      })
    }

经过这样修改，上传的过程可以在FileService.uploadImage中控制，上传后结果返回到on-success回调的第一个参数中。进度会传回FileService.uploadImage第二个参数指向的函数中。
最终代码

<script>
import FileService from '@/request/file/File'
export default {
  name: 'AdminComponentsUpload',
  data () {
    return {
      imageUrl: ''
    }
  },
  created () {},
  methods: {
    handleUploadImage (options) {
      return new Promise((resolve, reject) => {
        FileService.uploadImage(options.file, options.onProgress).then(res => {
          resolve(res)
        }).catch(error => {
          this.$message.error(error || '上传图片失败!')
        })
      })
    },
    beforeAvatarUpload (file) {
      const isJPG = file.type === 'image/jpeg'
      const isLt2M = file.size / 1024 / 1024 < 2
      if (!isJPG) {
        this.$message.error('上传头像图片只能是 JPG 格式!')
      }
      if (!isLt2M) {
        this.$message.error('上传头像图片大小不能超过 2MB!')
      }
      return isJPG && isLt2M
    },
    handleAvatarSuccess (res, file) {
      this.imageUrl = URL.createObjectURL(file.raw)
    },
    handleRemove (file, fileList) {
      console.log(file, fileList)
    },
    handlePictureCardPreview (file) {
      console.log(file)
    }
  }
}
</script>

<template>
  <el-main>
    <el-scrollbar class="default-scrollbar" wrap-class="default-scrollbar__wrap" view-class="p20-scrollbar__view">
      <h2 class="title">用户头像上传</h2>
      <div class="avater-wrap">
        <el-upload
          class="avatar-uploader"
          action="upload"
          :show-file-list="false"
          :http-request="handleUploadImage"
          :on-success="handleAvatarSuccess"
          :before-upload="beforeAvatarUpload">
          <img v-if="imageUrl" :src="imageUrl" class="avatar">
          <i v-else class="el-icon-plus avatar-uploader-icon"></i>
        </el-upload>
      </div>
      <h2 class="title">照片墙</h2>
      <div class="wall-wrap">
        <el-upload
          action="upload"
          list-type="picture-card"
          :http-request="handleUploadImage"
          :on-preview="handlePictureCardPreview"
          :on-remove="handleRemove">
          <i class="el-icon-plus"></i>
        </el-upload>
      </div>
    </el-scrollbar>
  </el-main>
</template>

<!-- Add "scoped" attribute to limit CSS to this component only -->
<style scoped>
.title {
  line-height: 60px;
}
.avater-wrap {
  width: 180px;
  height: 180px;
}
.avatar-uploader {
  border: 1px dashed #d9d9d9;
  border-radius: 6px;
  cursor: pointer;
  position: relative;
  overflow: hidden;
}
.avatar-uploader:hover {
  border-color: #409EFF;
}
.avatar-uploader-icon {
  font-size: 28px;
  color: #8c939d;
  width: 178px;
  height: 178px;
  line-height: 178px;
  text-align: center;
}
.avatar {
  width: 178px;
  height: 178px;
  display: block;
}
</style>