from flask import Flask, send_file
import os
<p>app = Flask(<strong>name</strong>)</p><p>@app.route('/download')
def download_file():</p><h1>文件在服务器上的路径</h1><pre class='brush:python;toolbar:false;'>file_path = 'example.txt'

# 检查文件是否存在
if not os.path.exists(file_path):
    return "文件未找到", 404

# 发送文件供下载
return send_file(file_path, as_attachment=True)

if name == 'main': app.run(debug=True)

from flask import Flask, send_from_directory
import os
<p>app = Flask(<strong>name</strong>)
UPLOAD_FOLDER = 'files'  # 存放可下载文件的目录</p><p>@app.route('/download/<filename>')
def download(filename):</p><h1>防止路径穿越攻击</h1><pre class='brush:python;toolbar:false;'>if '..' in filename or filename.startswith('/'):
    return "非法文件名", 400

file_path = os.path.join(UPLOAD_FOLDER, filename)
if not os.path.exists(file_path):
    return "文件不存在", 404

# 自定义下载时的文件名（可选）
return send_from_directory(UPLOAD_FOLDER, filename, as_attachment=True)

@app.route('/')
def index():
    return '''
    <h2>文件下载</h2>
    <a href="/download/example.txt">点击下载example.txt</a>
    '''

from io import BytesIO
<p>@app.route('/download/csv')
def download_csv():</p><h1>模拟生成CSV内容</h1><pre class='brush:python;toolbar:false;'>csv_content = "姓名,年龄\n张三,25\n李四,30"
mem = BytesIO()
mem.write(csv_content.encode('utf-8'))
mem.seek(0)

return send_file(
    mem,
    mimetype='text/csv',
    as_attachment=True,
    download_name='data.csv'  # 设置下载文件名
)