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I am trying to build a URL following the instructions of the flask tutorial
http://flask.pocoo.org/docs/0.11/quickstart/
However I am keeping getting this NameError
name 'url_for' is not defined
THIS is the code :
from flask import Flask
app = Flask(__name__)
@app.route('/')
def Index() : pass
@app.route ('/ login')
def loGin() : pass
@app.route('/user/<username>')
def profile( username) : pass
with app.test_request_context() :
print url_for('Index')
print url_for('loGin')
print url_for('loGin', next='/')
print url_for('profile', username = 'Jon DD')
THIS is the total error message :
eloiim:minimalapp iivri.andre$ export FLASK_APP=Greet.py
eloiim:minimalapp iivri.andre$ flask run
Traceback (most recent call last):
File "/usr/local/bin/flask", line 11, in <module>
sys.exit(main())
File "/usr/local/lib/python2.7/site-packages/flask/cli.py", line 478, in main
cli.main(args=args, prog_name=name)
File "/usr/local/lib/python2.7/site-packages/flask/cli.py", line 345, in main
return AppGroup.main(self, *args, **kwargs)
File "/usr/local/lib/python2.7/site-packages/click/core.py", line 696, in main
rv = self.invoke(ctx)
File "/usr/local/lib/python2.7/site-packages/click/core.py", line 1060, in invoke
return _process_result(sub_ctx.command.invoke(sub_ctx))
File "/usr/local/lib/python2.7/site-packages/click/core.py", line 889, in invoke
return ctx.invoke(self.callback, **ctx.params)
File "/usr/local/lib/python2.7/site-packages/click/core.py", line 534, in invoke
return callback(*args, **kwargs)
File "/usr/local/lib/python2.7/site-packages/click/decorators.py", line 64, in new_func
return ctx.invoke(f, obj, *args[1:], **kwargs)
File "/usr/local/lib/python2.7/site-packages/click/core.py", line 534, in invoke
return callback(*args, **kwargs)
File "/usr/local/lib/python2.7/site-packages/flask/cli.py", line 388, in run_command
app = DispatchingApp(info.load_app, use_eager_loading=eager_loading)
File "/usr/local/lib/python2.7/site-packages/flask/cli.py", line 124, in __init__
self._load_unlocked()
File "/usr/local/lib/python2.7/site-packages/flask/cli.py", line 148, in _load_unlocked
self._app = rv = self.loader()
File "/usr/local/lib/python2.7/site-packages/flask/cli.py", line 209, in load_app
rv = locate_app(self.app_import_path)
File "/usr/local/lib/python2.7/site-packages/flask/cli.py", line 89, in locate_app
__import__(module)
File "/Users/iivri.andre/Documents/minimalapp/Greet.py", line 16, in <module>
print url_for('Index')
NameError: name 'url_for' is not defined
I am not sure what the issue is.
428
The url_for() function is very useful for dynamically building a URL for a specific function. The function accepts the name of a function as first argument, and one or more keyword arguments, each corresponding to the variable part of URL. The following script demonstrates use of url_for() function.
url_for in Flask is used for creating a URL to prevent the overhead of having to change URLs throughout an application (including in templates). Without url_for , if there is a change in the root URL of your app then you have to change it in every page where the link is present.
Add it to your import line:
from flask import Flask, url_for
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