flask mongodb文件的上传和下载 前后端代码

后端代码：

1. 安装flask和pymongo库

pip install flask pymongo

2. 创建Flask应用程序，配置数据库连接

from flask import Flask, request, send_file
from pymongo import MongoClient

app = Flask(__name__)

# 配置数据库连接
client = MongoClient('mongodb://localhost:27017/')
db = client['test']
collection = db['files']

3. 编写文件上传接口

@app.route('/upload', methods=['POST'])
def upload_file():
    file = request.files['file']
    filename = file.filename
    # 将文件保存到MongoDB数据库中
    collection.insert_one({'filename': filename, 'file': file.read()})
    return '文件上传成功'

4. 编写文件下载接口

@app.route('/download/<filename>', methods=['GET'])
def download_file(filename):
    # 从数据库中查询文件
    file = collection.find_one({'filename': filename})
    # 将文件下载到本地
    return send_file(file['file'], attachment_filename=file['filename'], as_attachment=True)

前端代码：

1. HTML页面中添加上传和下载按钮

<form action="/upload" method="post" enctype="multipart/form-data">
    <input type="file" name="file">
    <button type="submit">上传文件</button>
</form>

<a href="/download/test.txt">下载文件</a>

2. 使用JavaScript实现文件上传和下载

// 文件上传
let fileInput = document.querySelector('input[type="file"]');
let uploadButton = document.querySelector('button[type="submit"]');

uploadButton.addEventListener('click', () => {
    let formData = new FormData();
    formData.append('file', fileInput.files[0]);
    fetch('/upload', {
        method: 'POST',
        body: formData
    }).then(response => {
        console.log(response.text());
    });
});

// 文件下载
let downloadLink = document.querySelector('a[href^="/download/"]');
downloadLink.addEventListener('click', event => {
    event.preventDefault();
    let filename = downloadLink.getAttribute('href').split('/').pop();
    fetch(`/download/${filename}`).then(response => {
        response.blob().then(blob => {
            let url = URL.createObjectURL(blob);
            let a = document.createElement('a');
            a.href = url;
            a.download = filename;
            a.click();
        });
    });
});