最简单的hello world
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#!/usr/bin/env python
# encoding: utf-8
fromflask importFlask
app=Flask(__name__)
@app.route('/')
defindex():
return'hello world'
if__name__=='__main__':
app.run(debug=True)
#app.run(host='127.0.0.1', port=8000)
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支持post/get提交
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@app.route('/',methods=['GET','POST'])
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多个url指向
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@app.route('/')
@app.route('/index')
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不管post/get使用统一的接收
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fromflask importrequest
args=request.args ifrequest.method=='GET'elserequest.form
a=args.get('a','default')
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处理json请求
request的header中
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"Content-Type":"application/json"
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处理时:
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data=request.get_json(silent=False)
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获取post提交中的checkbox
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{%forpage inpages%}
<tr><td><input type=checkbox name=do_delete value="{{ page['id'] }}"></td><td>
{%endfor%}
page_ids=request.form.getlist("do_delete")
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使用url中的参数
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@app.route('/query/<qid>/')
def query(qid):
pass
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在request开始结束dosomething
一般可以处理数据库连接等等
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fromflask importg
app=.....
@app.before_request
defbefore_request():
g.session=create_session()
@app.teardown_request
defteardown_request(exception):
g.session.close()
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注册Jinja2模板中使用的过滤器
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@app.template_filter('reverse')
defreverse_filter(s):
returns[::-1]
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或者
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defreverse_filter(s):
returns[::-1]
app.jinja_env.filters['reverse']=reverse_filter
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可以这么用
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defa():...
defb():...
FIL={'a':a,'b':b}
app.jinja_env.filters.update(FIL)
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注册Jinja2模板中使用的全局变量
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JINJA2_GLOBALS={'MEDIA_PREFIX':'/media/'}
app.jinja_env.globals.update(JINJA2_GLOBALS)
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定义应用使用的template和static目录
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app=Flask(__name__,template_folder=settings.TEMPLATE_FOLDER,static_folder=settings.STATIC_PATH)
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使用Blueprint
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fromflask importBlueprint
bp_test=Blueprint('test',__name__)
#bp_test = Blueprint('test', __name__, url_prefix='/abc')
@bp_test.route('/')
--------
fromxxx importbp_test
app=Flask(__name__)
app.register_blueprint(bp_test)
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实例:
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bp_video=Blueprint('video',__name__,url_prefix='/kw_news/video')
@bp_video.route('/search/category/',methods=['POST','GET'])
#注意这种情况下Blueprint中url_prefix不能以 '/' 结尾, 否则404
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使用session
包装cookie实现的，没有session id
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app.secret_key='PS#yio`%_!((f_or(%)))s'
# 然后
fromflask importsession
session['somekey']=1
session.pop('logged_in',None)
session.clear()
#过期时间,通过cookie实现的
fromdatetimeimporttimedelta
session.permanent=True
app.permanent_session_lifetime=timedelta(minutes=5)
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反向路由
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fromflask importurl_for,render_template
@app.route("/")
defhome():
login_uri=url_for("login",next=url_for("home"))
returnrender_template("home.html",**locals())
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上传文件
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<form action="/image/upload/"method="post"enctype="multipart/form-data">
<input type="file"name="upload"/>
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接收
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f=request.files.get('upload')
img_data=f.read()
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直接返回某个文件
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returnsend_file(settings.TEMPLATE_FOLDER+'tweet/tweet_list.html')
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请求重定向
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@app.route('/')
defhello():
returnredirect(url_for('foo'))
@app.route('/foo')
deffoo():
return'Hello Foo!'
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获取用户真实ip
从request.headers获取
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real_ip=request.headers.get('X-Real-Ip',request.remote_addr)
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或者, 使用werkzeug的middleware 文档
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fromwerkzeug.contrib.fixers importProxyFix
app.wsgi_app=ProxyFix(app.wsgi_app)
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return json & jsonp
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importjson
fromflask importjsonify,Response,json
data=[]# or others
returnjsonify(ok=True,data=data)
jsonp_callback= request.args.get('callback','')
ifjsonp_callback:
returnResponse(
"%s(%s);"%(jsonp_callback,json.dumps({'ok':True,'data':data})),
mimetype="text/javascript"
)
returnok_jsonify(data)
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配置读取方法
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# create our little application :)
app=Flask(__name__)
# Load default config and override config from an environment variable
app.config.update(dict(
DATABASE='/tmp/flaskr.db',
DEBUG=True,
SECRET_KEY='development key',
USERNAME='admin',
PASSWORD='default'
))
app.config.from_envvar('FLASKR_SETTINGS',silent=True)
------------------
# configuration
DATABASE='/tmp/minitwit.db'
PER_PAGE=30
DEBUG=True
SECRET_KEY='development key'
# create our little application :)
app=Flask(__name__)
app.config.from_object(__name__)
app.config.from_envvar('MINITWIT_SETTINGS',silent=True)
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几个不常用的方法
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fromflask importabort,flash
abort
ifnotsession.get('logged_in'):
abort(401)
flash
flash('New entry was successfully posted')
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异步调用
想在flask的一个请求中处理异步, 除了使用消息系统, 可以用简单的线程处理
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fromthreadingimportThread
defasync(f):
defwrapper(*args,**kwargs):
thr=Thread(target=f,args=args,kwargs=kwargs)
thr.start()
returnwrapper
@async
defdosomething(call_args):
printcall_args
inarequest handler,call`dosomething`
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error handler
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@app.errorhandler(404)
defnot_found_error(error):
returnrender_template('404.html'),404
@app.errorhandler(500)
definternal_error(error):
db.session.rollback()
returnrender_template('500.html'),500
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项目配置
1.直接
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app.config['HOST']='xxx.a.com'
printapp.config.get('HOST')
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2.环境变量
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export MyAppConfig=/path/to/settings.cfg
app.config.from_envvar('MyAppConfig')
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3.对象
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classConfig(object):
DEBUG=False
TESTING=False
DATABASE_URI='sqlite://:memory:'
classProductionConfig(Config):
DATABASE_URI='mysql://user@localhost/foo'
app.config.from_object(ProductionConfig)
printapp.config.get('DATABASE_URI')# mysql://user@localhost/foo
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4.文件
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# default_config.py
HOST='localhost'
PORT=5000
DEBUG=True
app.config.from_pyfile('default_config.py')
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EG. 一个create_app方法
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fromflask importFlask,g
defcreate_app(debug=settings.DEBUG):
app=Flask(__name__,
template_folder=settings.TEMPLATE_FOLDER,
static_folder=settings.STATIC_FOLDER)
app.register_blueprint(bp_test)
app.jinja_env.globals.update(JINJA2_GLOBALS)
app.jinja_env.filters.update(JINJA2_FILTERS)
app.secret_key='PO+_)(*&678OUIJKKO#%_!(((%)))'
@app.before_request
defbefore_request():
g.xxx=... #do some thing
@app.teardown_request
defteardown_request(exception):
g.xxx=... #do some thing
returnapp
app=create_app(settings.DEBUG)
host=settings.SERVER_IP
port=settings.SERVER_PORT
app.run(host=host,port=port)
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