python flask 如何修改默認(rèn)端口號的方法步驟
更新時間：2019年07月12日 10:05:46 作者：都是一家人
這篇文章主要介紹了python flask 如何修改默認(rèn)端口號的方法步驟，文中通過示例代碼介紹的非常詳細(xì)，對大家的學(xué)習(xí)或者工作具有一定的參考學(xué)習(xí)價值，需要的朋友們下面隨著小編來一起學(xué)習(xí)學(xué)習(xí)吧
場景：按照github文檔上啟動一個flask的app，默認(rèn)是用5000端口，如果5000端口被占用，啟動失敗。
樣例代碼：
from flask import Flask
app = Flask(__name__)
@app.route('/')
def hello():
return 'Hello, World!'
啟動的腳本：
$ env FLASK_APP=hello.py flask run
出錯信息如下：
renjg@renjg-HP-Compaq-Pro-6380-MT:~/WorkSpace/python/django$ env FLASK_APP=index.py flask run * Serving Flask app "index.py" * Environment: production WARNING: Do not use the development server in a production environment. Use a production WSGI server instead. * Debug mode: off Traceback (most recent call last): File "/usr/local/bin/flask", line 11, in <module> sys.exit(main()) File "/usr/local/lib/python2.7/dist-packages/flask/cli.py", line 894, in main cli.main(args=args, prog_name=name) File "/usr/local/lib/python2.7/dist-packages/flask/cli.py", line 557, in main return super(FlaskGroup, self).main(*args, **kwargs) File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 717, in main rv = self.invoke(ctx) File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 1137, in invoke return _process_result(sub_ctx.command.invoke(sub_ctx)) File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 956, in invoke return ctx.invoke(self.callback, **ctx.params) File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 555, in invoke return callback(*args, **kwargs) File "/usr/local/lib/python2.7/dist-packages/click/decorators.py", line 64, in new_func return ctx.invoke(f, obj, *args, **kwargs) File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 555, in invoke return callback(*args, **kwargs) File "/usr/local/lib/python2.7/dist-packages/flask/cli.py", line 771, in run_command threaded=with_threads, ssl_context=cert) File "/usr/local/lib/python2.7/dist-packages/werkzeug/serving.py", line 814, in run_simple inner() File "/usr/local/lib/python2.7/dist-packages/werkzeug/serving.py", line 774, in inner fd=fd) File "/usr/local/lib/python2.7/dist-packages/werkzeug/serving.py", line 660, in make_server passthrough_errors, ssl_context, fd=fd) File "/usr/local/lib/python2.7/dist-packages/werkzeug/serving.py", line 577, in __init__ self.address_family), handler) File "/usr/lib/python2.7/SocketServer.py", line 417, in __init__ self.server_bind() File "/usr/lib/python2.7/BaseHTTPServer.py", line 108, in server_bind SocketServer.TCPServer.server_bind(self) File "/usr/lib/python2.7/SocketServer.py", line 431, in server_bind self.socket.bind(self.server_address) File "/usr/lib/python2.7/socket.py", line 228, in meth return getattr(self._sock,name)(*args) socket.error: [Errno 98] Address already in use
問題：
那么該怎么指定新的端口呢？又如何查看5000端口指定的位置呢？
源碼分析，首先clone github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$ grep 5000 * -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: * Running on http://127.0.0.1:5000/
docs/config.rst:453: * Running on http://127.0.0.1:5000/
docs/quickstart.rst:51: * Running on http://127.0.0.1:5000/
docs/quickstart.rst:66: * Running on http://127.0.0.1:5000/
docs/quickstart.rst:72:Now head over to `http://127.0.0.1:5000/ <http://127.0.0.1:5000/>`_, and you
docs/deploying/wsgi-standalone.rst:38: $ uwsgi --http 127.0.0.1:5000 --module myproject:app
docs/deploying/wsgi-standalone.rst:55: http_server = WSGIServer(('', 5000), app)
docs/server.rst:26:*http://localhost:5000/*.
docs/cli.rst:97: * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
docs/cli.rst:143: * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
docs/tutorial/static.rst:58:Go to http://127.0.0.1:5000/auth/login and the page should look like the
docs/tutorial/factory.rst:169: * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
docs/tutorial/factory.rst:174:Visit http://127.0.0.1:5000/hello in a browser and you should see the
docs/tutorial/templates.rst:174:then go to http://127.0.0.1:5000/auth/register.
examples/javascript/README.rst:39:Open http://127.0.0.1:5000 in a browser.
examples/tutorial/README.rst:62:Open http://127.0.0.1:5000 in a browser.
<strong>flask/app.py:878: :param port: the port of the webserver. Defaults to ``5000`` or the
flask/app.py:925: _port = 5000
flask/cli.py:738:@click.option('--port', '-p', default=5000,</strong>
README.rst:43: * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
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') does not match the "
可以看到在flask/app.py 以及cli.py中有指定。那么根據(jù)啟動命令flask run 實際上是啟動了一個http server，然后監(jiān)聽了一個本地端口，等待連接。那么看看是否有相應(yīng)的參數(shù)。
renjg@renjg-HP-Compaq-Pro-6380-MT:~/WorkSpace/python/django/flask$ flask --help
Traceback (most recent call last):
File "/usr/local/lib/python2.7/dist-packages/flask/cli.py", line 529, in list_commands
rv.update(info.load_app().cli.list_commands(ctx))
File "/usr/local/lib/python2.7/dist-packages/flask/cli.py", line 384, in load_app
'Could not locate a Flask application. You did not provide '
NoAppException: Could not locate a Flask application. You did not provide the "FLASK_APP" environment variable, and a "wsgi.py" or "app.py" module was not found in the current directory.
Usage: flask [OPTIONS] COMMAND [ARGS]...
A general utility script for Flask applications.
Provides commands from Flask, extensions, and the application. Loads the
application defined in the FLASK_APP environment variable, or from a
wsgi.py file. Setting the FLASK_ENV environment variable to 'development'
will enable debug mode.
$ export FLASK_APP=hello.py
$ export FLASK_ENV=development
$ flask run
Options:
--version Show the flask version
--help Show this message and exit.
Commands:
routes Show the routes for the app.
run Runs a development server.
shell Runs a shell in the app context.
renjg@renjg-HP-Compaq-Pro-6380-MT:~/WorkSpace/python/django/flask$ flask run --help
Usage: flask run [OPTIONS]
Run a local development server.
This server is for development purposes only. It does not provide the
stability, security, or performance of production WSGI servers.
The reloader and debugger are enabled by default if FLASK_ENV=development
or FLASK_DEBUG=1.
Options:
-h, --host TEXT The interface to bind to.
<strong> -p, --port INTEGER The port to bind to.</strong>
--cert PATH Specify a certificate file to use HTTPS.
--key FILE The key file to use when specifying a
certificate.
--reload / --no-reload Enable or disable the reloader. By default
the reloader is active if debug is enabled.
--debugger / --no-debugger Enable or disable the debugger. By default
the debugger is active if debug is enabled.
--eager-loading / --lazy-loader
Enable or disable eager loading. By default
eager loading is enabled if the reloader is
disabled.
--with-threads / --without-threads
Enable or disable multithreading.
--help Show this message and exit.
可以看到有-p這個參數(shù)，是指定端口的，默認(rèn)是5000，那么嘗試修改一下。
renjg@renjg-HP-Compaq-Pro-6380-MT:~/WorkSpace/python/django$ env FLASK_APP=index.py flask run -p 5001 * Serving Flask app "index.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://127.0.0.1:5001/ (Press CTRL+C to quit)
還一個5001的端口就成功了，由此可知，當(dāng)出現(xiàn)一個我們不知道該如何解決問題的時候，我們可以嘗試著自己分析源碼，得到想要的結(jié)果。
以上就是本文的全部內(nèi)容，希望對大家的學(xué)習(xí)有所幫助，也希望大家多多支持腳本之家。
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