python flask 如何修改默认端口号的方法步骤

2023-08-20 02:18:04 87

场景：按照github文档上启动一个flask的app，默认是用5000端口，如果5000端口被占用，启动失败。

样例代码：

fromflaskimportFlask

app=Flask(__name__)

@app.route('/')
defhello():
return'Hello,World!'

启动的脚本：

$envFLASK_APP=hello.pyflaskrun

出错信息如下：

renjg@renjg-HP-Compaq-Pro-6380-MT:~/WorkSpace/python/django$envFLASK_APP=index.pyflaskrun
*ServingFlaskapp"index.py"
*Environment:production
WARNING:Donotusethedevelopmentserverinaproductionenvironment.
UseaproductionWSGIserverinstead.
*Debugmode:off
Traceback(mostrecentcalllast):
File"/usr/local/bin/flask",line11,in
sys.exit(main())
File"/usr/local/lib/python2.7/dist-packages/flask/cli.py",line894,inmain
cli.main(args=args,prog_name=name)
File"/usr/local/lib/python2.7/dist-packages/flask/cli.py",line557,inmain
returnsuper(FlaskGroup,self).main(*args,**kwargs)
File"/usr/local/lib/python2.7/dist-packages/click/core.py",line717,inmain
rv=self.invoke(ctx)
File"/usr/local/lib/python2.7/dist-packages/click/core.py",line1137,ininvoke
return_process_result(sub_ctx.command.invoke(sub_ctx))
File"/usr/local/lib/python2.7/dist-packages/click/core.py",line956,ininvoke
returnctx.invoke(self.callback,**ctx.params)
File"/usr/local/lib/python2.7/dist-packages/click/core.py",line555,ininvoke
returncallback(*args,**kwargs)
File"/usr/local/lib/python2.7/dist-packages/click/decorators.py",line64,innew_func
returnctx.invoke(f,obj,*args,**kwargs)
File"/usr/local/lib/python2.7/dist-packages/click/core.py",line555,ininvoke
returncallback(*args,**kwargs)
File"/usr/local/lib/python2.7/dist-packages/flask/cli.py",line771,inrun_command
threaded=with_threads,ssl_context=cert)
File"/usr/local/lib/python2.7/dist-packages/werkzeug/serving.py",line814,inrun_simple
inner()
File"/usr/local/lib/python2.7/dist-packages/werkzeug/serving.py",line774,ininner
fd=fd)
File"/usr/local/lib/python2.7/dist-packages/werkzeug/serving.py",line660,inmake_server
passthrough_errors,ssl_context,fd=fd)
File"/usr/local/lib/python2.7/dist-packages/werkzeug/serving.py",line577,in__init__
self.address_family),handler)
File"/usr/lib/python2.7/SocketServer.py",line417,in__init__
self.server_bind()
File"/usr/lib/python2.7/BaseHTTPServer.py",line108,inserver_bind
SocketServer.TCPServer.server_bind(self)
File"/usr/lib/python2.7/SocketServer.py",line431,inserver_bind
self.socket.bind(self.server_address)
File"/usr/lib/python2.7/socket.py",line228,inmeth
returngetattr(self._sock,name)(*args)
socket.error:[Errno98]Addressalreadyinuse

问题：

那么该怎么指定新的端口呢？又如何查看5000端口指定的位置呢？

源码分析，首先clonegithub上的flask框架，然后直接grep命令查看5000的位置。

renjg@renjg-HP-Compaq-Pro-6380-MT:~/WorkSpace/python/django/flask$grep5000*-nrw
docs/patterns/appdispatch.rst:28:run_simple('localhost',5000,application,use_reloader=True)
docs/patterns/appdispatch.rst:48:run_simple('localhost',5000,app,
docs/config.rst:417:*Runningonhttp://127.0.0.1:5000/
docs/config.rst:453:*Runningonhttp://127.0.0.1:5000/
docs/quickstart.rst:51:*Runningonhttp://127.0.0.1:5000/
docs/quickstart.rst:66:*Runningonhttp://127.0.0.1:5000/
docs/quickstart.rst:72:Nowheadoverto`http://127.0.0.1:5000/`_,andyou
docs/deploying/wsgi-standalone.rst:38:$uwsgi--http127.0.0.1:5000--modulemyproject:app
docs/deploying/wsgi-standalone.rst:55:http_server=WSGIServer(('',5000),app)
docs/server.rst:26:*http://localhost:5000/*.
docs/cli.rst:97:*Runningonhttp://127.0.0.1:5000/(PressCTRL+Ctoquit)
docs/cli.rst:143:*Runningonhttp://127.0.0.1:5000/(PressCTRL+Ctoquit)
docs/tutorial/static.rst:58:Gotohttp://127.0.0.1:5000/auth/loginandthepageshouldlooklikethe
docs/tutorial/factory.rst:169:*Runningonhttp://127.0.0.1:5000/(PressCTRL+Ctoquit)
docs/tutorial/factory.rst:174:Visithttp://127.0.0.1:5000/helloinabrowserandyoushouldseethe
docs/tutorial/templates.rst:174:thengotohttp://127.0.0.1:5000/auth/register.
examples/javascript/README.rst:39:Openhttp://127.0.0.1:5000inabrowser.
examples/tutorial/README.rst:62:Openhttp://127.0.0.1:5000inabrowser.
flask/app.py:878::paramport:theportofthewebserver.Defaultsto``5000``orthe
flask/app.py:925:_port=5000
flask/cli.py:738:@click.option('--port','-p',default=5000,
README.rst:43:*Runningonhttp://127.0.0.1:5000/(PressCTRL+Ctoquit)
tests/test_basic.py:369:SERVER_NAME='localhost:5000',
tests/test_basic.py:377:rv=client.get('/','http://localhost:5000/')
tests/test_basic.py:385:SERVER_NAME='127.0.0.1:5000',
tests/test_basic.py:393:rv=client.get('/','http://127.0.0.1:5000/')
tests/test_basic.py:1448:SERVER_NAME='localhost.localdomain:5000'
tests/test_basic.py:1463:rv=client.get('/','http://localhost.localdomain:5000')
tests/test_basic.py:1466:rv=client.get('/','https://localhost.localdomain:5000')
tests/test_reqctx.py:72:SERVER_NAME='localhost.localdomain:5000'
tests/test_reqctx.py:85:'http://localhost.localdomain:5000/'
tests/test_reqctx.py:89:'http://foo.localhost.localdomain:5000/'
tests/test_reqctx.py:97:"('localhost.localdomain:5000')doesnotmatchthe"

可以看到在flask/app.py以及cli.py中有指定。那么根据启动命令flaskrun实际上是启动了一个httpserver，然后监听了一个本地端口，等待连接。那么看看是否有相应的参数。

renjg@renjg-HP-Compaq-Pro-6380-MT:~/WorkSpace/python/django/flask$flask--help
Traceback(mostrecentcalllast):
File"/usr/local/lib/python2.7/dist-packages/flask/cli.py",line529,inlist_commands
rv.update(info.load_app().cli.list_commands(ctx))
File"/usr/local/lib/python2.7/dist-packages/flask/cli.py",line384,inload_app
'CouldnotlocateaFlaskapplication.Youdidnotprovide'
NoAppException:CouldnotlocateaFlaskapplication.Youdidnotprovidethe"FLASK_APP"environmentvariable,anda"wsgi.py"or"app.py"modulewasnotfoundinthecurrentdirectory.
Usage:flask[OPTIONS]COMMAND[ARGS]...

AgeneralutilityscriptforFlaskapplications.

ProvidescommandsfromFlask,extensions,andtheapplication.Loadsthe
applicationdefinedintheFLASK_APPenvironmentvariable,orfroma
wsgi.pyfile.SettingtheFLASK_ENVenvironmentvariableto'development'
willenabledebugmode.

$exportFLASK_APP=hello.py
$exportFLASK_ENV=development
$flaskrun

Options:
--versionShowtheflaskversion
--helpShowthismessageandexit.

Commands:
routesShowtheroutesfortheapp.
runRunsadevelopmentserver.
shellRunsashellintheappcontext.
renjg@renjg-HP-Compaq-Pro-6380-MT:~/WorkSpace/python/django/flask$flaskrun--help
Usage:flaskrun[OPTIONS]

Runalocaldevelopmentserver.

Thisserverisfordevelopmentpurposesonly.Itdoesnotprovidethe
stability,security,orperformanceofproductionWSGIservers.

ThereloaderanddebuggerareenabledbydefaultifFLASK_ENV=development
orFLASK_DEBUG=1.

Options:
-h,--hostTEXTTheinterfacetobindto.
-p,--portINTEGERTheporttobindto.
--certPATHSpecifyacertificatefiletouseHTTPS.
--keyFILEThekeyfiletousewhenspecifyinga
certificate.
--reload/--no-reloadEnableordisablethereloader.Bydefault
thereloaderisactiveifdebugisenabled.
--debugger/--no-debuggerEnableordisablethedebugger.Bydefault
thedebuggerisactiveifdebugisenabled.
--eager-loading/--lazy-loader
Enableordisableeagerloading.Bydefault
eagerloadingisenabledifthereloaderis
disabled.
--with-threads/--without-threads
Enableordisablemultithreading.
--helpShowthismessageandexit.

可以看到有-p这个参数，是指定端口的，默认是5000，那么尝试修改一下。

renjg@renjg-HP-Compaq-Pro-6380-MT:~/WorkSpace/python/django$envFLASK_APP=index.pyflaskrun-p5001
*ServingFlaskapp"index.py"
*Environment:production
WARNING:Donotusethedevelopmentserverinaproductionenvironment.
UseaproductionWSGIserverinstead.
*Debugmode:off
*Runningonhttp://127.0.0.1:5001/(PressCTRL+Ctoquit)

还一个5001的端口就成功了，由此可知，当出现一个我们不知道该如何解决问题的时候，我们可以尝试着自己分析源码，得到想要的结果。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持毛票票。

python flask 如何修改默认端口号的方法步骤

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