vue+django实现下载文件的示例

时间：2021-09-01 09:01:36|栏目：vue|点击：次

一、概述

在项目中，点击下载按钮，就可以下载文件。

传统的下载链接一般是get方式，这种链接是公开的，可以任意下载。

在实际项目，某些下载链接，是私密的。必须使用post方式，传递正确的参数，才能下载。

二、django项目

本环境使用django 3.1.5，新建项目download_demo

安装模块

pip3 install djangorestframework django-cors-headers

修改文件download_demo/settings.py

INSTALLED_APPS = [
 'django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'api.apps.ApiConfig',
 'corsheaders', # 注册应用cors
]

注册中间件

MIDDLEWARE = [
 'django.middleware.security.SecurityMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware',
 'corsheaders.middleware.CorsMiddleware', # 注册组件cors
]

最后一行增加

# 跨域增加忽略
CORS_ALLOW_CREDENTIALS = True
CORS_ORIGIN_ALLOW_ALL = True

CORS_ALLOW_METHODS = (
 'GET',
 'OPTIONS',
 'PATCH',
 'POST',
 'VIEW',
)

CORS_ALLOW_HEADERS = (
 'XMLHttpRequest',
 'X_FILENAME',
 'accept-encoding',
 'authorization',
 'content-type',
 'dnt',
 'origin',
 'user-agent',
 'x-csrftoken',
 'x-requested-with',
 'Pragma',
)

修改download_demo/urls.py

from django.contrib import admin
from django.urls import path
from api import views

urlpatterns = [
 path('admin/', admin.site.urls),
 path('download/excel/', views.ExcelFileDownload.as_view()),
]

修改api/views.py

from django.shortcuts import render,HttpResponse
from download_demo import settings
from django.utils.encoding import escape_uri_path
from django.http import StreamingHttpResponse
from django.http import JsonResponse
from rest_framework.views import APIView
from rest_framework import status
import os

class ExcelFileDownload(APIView):
 def post(self,request):
  print(request.data)
  # filename = "大江大河.xlsx"
  filename = request.data.get("filename")
  download_file_path = os.path.join(settings.BASE_DIR, "upload",filename)
  print("download_file_path",download_file_path)

  response = self.big_file_download(download_file_path, filename)
  if response:
   return response

  return JsonResponse({'status': 'HttpResponse', 'msg': 'Excel下载失败'})

 def file_iterator(self,file_path, chunk_size=512):
  """
  文件生成器,防止文件过大，导致内存溢出
  :param file_path: 文件绝对路径
  :param chunk_size: 块大小
  :return: 生成器
  """
  with open(file_path, mode='rb') as f:
   while True:
    c = f.read(chunk_size)
    if c:
     yield c
    else:
     break

 def big_file_download(self,download_file_path, filename):
  try:
   response = StreamingHttpResponse(self.file_iterator(download_file_path))
   # 增加headers
   response['Content-Type'] = 'application/octet-stream'
   response['Access-Control-Expose-Headers'] = "Content-Disposition, Content-Type"
   response['Content-Disposition'] = "attachment; filename={}".format(escape_uri_path(filename))
   return response
  except Exception:
   return JsonResponse({'status': status.HTTP_400_BAD_REQUEST, 'msg': 'Excel下载失败'},
        status=status.HTTP_400_BAD_REQUEST)

在项目根目录创建upload文件

里面放一个excel文件，比如：大江大河.xlsx

三、vue项目

新建一个vue项目，安装ElementUI 模块即可。

新建test.vue

<template>
 <div style="width: 70%;margin-left: 30px;margin-top: 30px;">
 <el-button class="filter-item" type="success" icon="el-icon-download" @click="downFile()">下载</el-button>
 </div>
</template>

<script>
 import axios from 'axios'

 export default {
 data() {
  return {
  }
 },
 mounted: function() {

 },
 methods: {
  downloadFile(url, options = {}){
  return new Promise((resolve, reject) => {
   // console.log(`${url} 请求数据，参数=>`, JSON.stringify(options))
   // axios.defaults.headers['content-type'] = 'application/json;charset=UTF-8'
   axios({
   method: 'post',
   url: url, // 请求地址
   data: options, // 参数
   responseType: 'blob' // 表明返回服务器返回的数据类型
   }).then(
   response => {
    // console.log("下载响应",response)
    resolve(response.data)
    let blob = new Blob([response.data], {
    type: 'application/vnd.ms-excel'
    })
    // console.log(blob)
    // let fileName = Date.parse(new Date()) + '.xlsx'
    // 切割出文件名
    let fileNameEncode = response.headers['content-disposition'].split("filename=")[1];
    // 解码
    let fileName = decodeURIComponent(fileNameEncode)
    // console.log("fileName",fileName)
    if (window.navigator.msSaveOrOpenBlob) {
    // console.log(2)
    navigator.msSaveBlob(blob, fileName)
    } else {
    // console.log(3)
    var link = document.createElement('a')
    link.href = window.URL.createObjectURL(blob)
    link.download = fileName
    link.click()
    //释放内存
    window.URL.revokeObjectURL(link.href)
    }
   },
   err => {
    reject(err)
   }
   )
  })
  },
  // 下载文件
  downFile(){
  let postUrl= "http://127.0.0.1:8000/download/excel/"
  let params = {
   filename: "大江大河.xlsx",
  }
  // console.log("下载参数",params)
  this.downloadFile(postUrl,params)
  },
 }
 }
</script>

<style>
</style>

注意：这里使用post请求，并将filename传输给api，用来下载指定的文件。

访问测试页面，点击下载按钮