Flask render_template() returning “NameError: name 'app' is not defined”

Question

I am following the Quickstart Guide for Flask. http://flask.pocoo.org/docs/quickstart/#static-files I'm getting this error as I follow the guide.

/application
/__init__.py
/templates
    /hello.html

   @app.route('/hello/')
   @app.route('/hello/<name>')
   def hello(name=None):
       return render_template('hello.html', name=name)

    >python _init_.py 
        Traceback (most recent call last):
        File "_init_.py", line 4, in <module>
   @app.route('/hello/')
   NameError: name 'app' is not defined

Answer 1

Perhaps this?

from flask import Flask, request, render_template

Answer 2

唯一缺少的是

from flask import Flask, render_template

Answer 3

Look at the minimal program on the Flask website , especially the first two lines:

from flask import Flask
app = Flask(__name__)

@app.route("/")
def hello():
    return "Hello World!"

if __name__ == "__main__":
    app.run()

You problem is that you haven't imported a Flask module and haven't initialized a Flask app object .

Answer 4

I am surprised no one has marked this question answered. As many have suggested, I can also confirm that from flask import Flask, render_template solves the problem

Answer 5

You need to:

from flask import request

I think its a flaw in Flask's quickstart guide.