Python编程中flask的简介与简单使用

Python  /  管理员 发布于 7年前   222

flask是一个纯python实现的开源microframework，使用flask可以像java的spring boot一样快速开始基于RestApi的微服务开发。

概要信息

事前准备

python和pip

[root@liumiaocn ~]# python --versionPython 2.7.5[root@liumiaocn ~]# pip --versionpip 10.0.1 from /usr/lib/python2.7/site-packages/pip (python 2.7)[root@liumiaocn ~]#

安装flask

[root@liumiaocn ~]# pip install flaskCollecting flask Downloading https://files.pythonhosted.org/packages/7f/e7/08578774ed4536d3242b14dacb4696386634607af824ea997202cd0edb4b/Flask-1.0.2-py2.py3-none-any.whl (91kB)  100% |################################| 92kB 92kB/s Collecting Jinja2>=2.10 (from flask) Downloading https://files.pythonhosted.org/packages/7f/ff/ae64bacdfc95f27a016a7bed8e8686763ba4d277a78ca76f32659220a731/Jinja2-2.10-py2.py3-none-any.whl (126kB)  100% |################################| 133kB 210kB/s Collecting itsdangerous>=0.24 (from flask) Downloading https://files.pythonhosted.org/packages/dc/b4/a60bcdba945c00f6d608d8975131ab3f25b22f2bcfe1dab221165194b2d4/itsdangerous-0.24.tar.gz (46kB)  100% |################################| 51kB 469kB/s Requirement already satisfied: Werkzeug>=0.14 in /usr/lib64/python2.7/site-packages (from flask) (0.14.1)Collecting click>=5.1 (from flask) Downloading https://files.pythonhosted.org/packages/34/c1/8806f99713ddb993c5366c362b2f908f18269f8d792aff1abfd700775a77/click-6.7-py2.py3-none-any.whl (71kB)  100% |################################| 71kB 229kB/s Collecting MarkupSafe>=0.23 (from Jinja2>=2.10->flask) Downloading https://files.pythonhosted.org/packages/4d/de/32d741db316d8fdb7680822dd37001ef7a448255de9699ab4bfcbdf4172b/MarkupSafe-1.0.tar.gzBuilding wheels for collected packages: itsdangerous, MarkupSafe Running setup.py bdist_wheel for itsdangerous ... done Stored in directory: /root/.cache/pip/wheels/2c/4a/61/5599631c1554768c6290b08c02c72d7317910374ca602ff1e5 Running setup.py bdist_wheel for MarkupSafe ... done Stored in directory: /root/.cache/pip/wheels/33/56/20/ebe49a5c612fffe1c5a632146b16596f9e64676768661e4e46Successfully built itsdangerous MarkupSafeInstalling collected packages: MarkupSafe, Jinja2, itsdangerous, click, flaskSuccessfully installed Jinja2-2.10 MarkupSafe-1.0 click-6.7 flask-1.0.2 itsdangerous-0.24[root@liumiaocn ~]

安装确认

[root@liumiaocn ~]# pip show flaskName: FlaskVersion: 1.0.2Summary: A simple framework for building complex web applications.Home-page: https://www.palletsprojects.com/p/flask/Author: Armin RonacherAuthor-email: [email protected]: BSDLocation: /usr/lib64/python2.7/site-packagesRequires: Jinja2, itsdangerous, Werkzeug, clickRequired-by: [root@liumiaocn ~]#

flask安装之后，也可以用如下方法进行确认

[root@liumiaocn ~]# which flask /usr/bin/flask[root@liumiaocn ~]# flask --versionFlask 1.0.2Python 2.7.5 (default, Aug 4 2017, 00:39:18) [GCC 4.8.5 20150623 (Red Hat 4.8.5-16)][root@liumiaocn ~]#

第一个HelloWorld

代码示例

[root@liumiaocn ~]# cat hello_flask.py from flask import Flaskapp = Flask(__name__)@app.route("/")def hello():  return "Hello World!"[root@liumiaocn ~]#

执行&确认

[root@liumiaocn ~]# FLASK_APP=hello_flask.py flask run * Serving Flask app "hello_flask.py" * Environment: production  WARNING: Do not use the development server in a production environment.  Use a production WSGI server instead. * Debug mode: off * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)

通过curl进行结果确认：

[root@liumiaocn ~]# curl http://localhost:5000Hello World![root@liumiaocn ~]#

代码示例

另外也可以通过使用app.run方法启动服务：

[root@liumiaocn ~]# cat hello_flask_2.py from flask import Flaskapp = Flask(__name__)@app.route("/")def hello():  return "Hello World!"if __name__ == "__main__":  app.run()[root@liumiaocn ~]#

执行&确认

[root@liumiaocn ~]# python hello_flask_2.py  * Serving Flask app "hello_flask_2" (lazy loading) * Environment: production  WARNING: Do not use the development server in a production environment.  Use a production WSGI server instead. * Debug mode: off * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)

通过curl进行结果确认：

[root@liumiaocn ~]# curl http://localhost:5000Hello World![root@liumiaocn ~]#

外部可访问的设定方法

可以通过如下方式进行设定可从网络的其他机器对此服务进行访问：

app.run(host='0.0.0.0')

设定端口号

缺省使用5000端口进行监听，如果需要修改，可以使用如下方式：

app.run(port=6000)

设定debug模式

可以使用如下方式打开Debug模式

app.debug = Trueapp.run()

或者

app.run(debug=True)

小结

对spring boot了解的开发者可能会发现这里基本和spring的requestmapping几乎如出一辙，至少在restapi的实现上有相似之处。设定和实现起来非常地方便，这就是flask用于web开发入门的简单之处。

总结

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