Python有两大Web应用开发框架，其中之一的后起之秀Flask虽然起步较晚，但很快赢得了广大开发者的热爱。最大的特点就是轻量、上手快，以下我们来演示如何创建一个简单的Flask应用。
一个简单的Flask应用
from flask
import Flask
app
= Flask
(__name__
)
@app
.route
("/")
def index():
return "Welcome back, I'm missing you all the time."
if __name__
== "__main__":
app
.run
()
Flask常用的一些方法如下。
路由
@app
.route
('/about')
def about():
return 'The about page'
@app
.route
('/path/<path:sub_path>')
def show_sub_path(sub_path
):
return 'Sub Path %s' % escape
(sub_path
)
传参（三种形式）
@app
.route
('/search')
def search():
return 'keywords: %s' % request
.args
.get
('keywords', 'none')
@app
.route
('/user/<username>')
def show_user_profile(username
):
return 'User %s' % escape
(username
)
@app
.route
('/post/<int:post_id>')
def show_post(post_id
):
return 'Post %d' % post_id
返回JSON数据
@app
.route
('/me')
def me_api():
user
= {'name': 'sunny', 'theme': 'default', 'tel': '15800001234'}
return jsonify
(user
)
文件上传
@app
.route
('/upload', methods
=['GET', 'POST'])
def upload_file():
if request
.method
!= 'POST':
return
f
= request
.files
['the_file']
f
.save
('/var/www/uploads/uploaded_file.txt')
返回错误码
@app
.route
('/login')
def login():
abort
(401)
异常处理
@app
.errorhandler
(404)
def page_not_found(error
):
print(error
)
return render_template
('404.html'), 404
@app
.errorhandler
(500)
def page_not_found(error
):
print(error
)
return render_template
('500.html'), 500
