building flask with virtualenv

  • install virtualenv
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pip install virtualenv
  • setup a project with virtualenv
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virtualenv helloflask
  • activate your project
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cd helloflask
source bin/activate ('deactivate' is another command)
  • install flask
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pip install flask
#This installs Flask, Werkzeug (a utility library) 
and Jinja (a templating framework).
  • create app.py
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from flask import Flask
app = Flask(__name__)
@app.route("/")
def hello():
    return "Hello World!"
if __name__ == "__main__":
    app.run()
  • run your app
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python app.py

deploy to heroku

  • install gunicorn
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# Heroku seems to prefer a web server called gunicorn
pip install gunicorn
  • add a requirements.txt
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pip freeze -l > requirements.txt
  • add a runtime.txt to specify your python version
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# get your python version: python --version
vim runtime.txt
python-3.6.2
  • create a Procfile (app:app the first app should your python file name)
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vim Procfile
web: gunicorn app:app
  • git & heroku
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git init
git add .
git commit -m "first draft"
# you should know some knowledge about heroku login before 
heroku create # will create a ***.git
#if you do heroku create before git init, you should use below command
git remote add heroku https://git.heroku.com/gentle-dawn-27343.git
git push heroku master
heroku open