Cloud9 "Unable to load http preview" Flask project - python

I'm following a mooc for building quickly a website in flask.
I'm using Cloud9 but i'm unable to watch my preview on it, i get an :
"Unable to load http preview" :
the code is really simple, here the views.py code
from flask import Flask, render_template
app = Flask(__name__)
# Config options - Make sure you created a 'config.py' file.
app.config.from_object('config')
# To get one variable, tape app.config['MY_VARIABLE']
#app.route('/')
def index():
return "Hello world !"
if __name__ == "__main__":
app.run()
And the preview screen, is what I get when I execute
python views.py
Thank you in advance

you need to make FLASK_APP environment variable, and flask application is not running like python views.py but flask run. Quick start
# give an environment variable, give the absolute path or relative
# path to you flask app, in your case it is `views.py`
export FLASK_APP=views.py
#after this run flask application
flask run

I faced the same problem. There is no way we can preview http endpoints directly. Although in AWS documentation they have asked to follow certain steps, but those too wont work. Only way is to access it using instance public address and exposing required ports. Read here for this.

Related

Flask authentication using htpassword with routes in seperate files

I'm working on updating an existing university department internal website to run using Flask. Before we completely release the project where it will use shibboleth to manage authentication, I've been trying to setup authentication for testing using htpassword using this tutorial. I'm able to get authentication using htpasswords working for a single file, but I can't figure out how to add the authentication to separate files. Currently, the project looks like this:
This is my main file called app.py:
#app.py
from flask import Flask
from flask_htpasswd import HtPasswdAuth
app = Flask(__name__)
app.config['FLASK_HTPASSWD_PATH'] = '.htpasswd'
app.config['FLASK_SECRET'] = "Super secret key that I will change later"
htpasswd = HtPasswdAuth(app)
import exampleRoute
#app.route('/')
#htpasswd.required
def home(user):
return "This is the homepage"
This is an example of one of my route files called exampleRoute.py:
# exampleRoute.py
from app import app
from flask import Flask
#app.route('/exampleRoute')
def exampleRoute():
return "This is an example route in another file"
When I place the #htpassword.required decorator in front of exampleRoute(), I get an error saying that htpassword is not defined (which makes sense). I've tried to import the app configuration a few different ways and at best, I end up with a circular dependency. I know that I could place the authentication code in a separate file and then import that into all my endpoints, but I didn't think this was possible since this method is incorporated into the app configuration.
I ended up getting an answer from the reddit user alexisprince. The solution was to use Blueprints that import htpasswd from another file (called extensions.py).

Unsure how to configure WSGI handler/Flask to enable cron job in Python/App Engine

I have the following code which works successfully when I deploy it on App Engine. Except I want to run it with a cron.
import pandas as pd
import requests
from flask import Flask
app = Flask(__name__)
#app.route('/')
def sfLibraries():
return 'Success'
if __name__ == '__main__':
app.run(host='127.0.0.1', port=8080, debug=True)
cron.yaml
cron:
- description: "SF Loader"
url: /task/loader
schedule: every 1 hours
app.yaml
runtime: python38
handlers:
- url: /task/loader
script: auto
I know that if I change #app.route('/') to #app.route('/task/loader') that the cron will work successfully, yet I lose the capability to go to the site when I first deploy it and see success.
gcloud app browse
Did not detect your browser. Go to this link to view your app:
https://<<<my_synapse>>>.uc.r.appspot.com
https://<<<my_synapse>>>.uc.r.appspot.com:
Not Found
The requested URL was not found on the server. If you entered the URL manually please check your spelling and try again.
How can I have it both ways -both able to go to the site via gcloud app browse and see success as well as run the cron successfully?
I mentioned WSGI Handler because I found this pertinent post but not sure how WSGI Handler might help or improve from what Flask is doing Setting up cron job in google app engine python
Create two different routes to accomplish what you need. The functions must have a different name in this case.
#app.route('/')
def sfLibraries():
return 'Success'
#app.route('/task/loader')
def sfLibrariesSecond():
return 'Success'
Assign different actions for each one.
They could also both do the exact same thing. If that was the case, then assign two routes to the same function.
#app.route('/')
#app.route('/task/loader')
def sfLibraries():
return 'Success'

Trading view alerts to trigger market order through python and Oanda's API

I'm trying to trigger a python module (market order for Oanda) using web hooks(from trading view).
Similar to this
1) https://www.youtube.com/watch?v=88kRDKvAWMY&feature=youtu.be
and this
2)https://github.com/Robswc/tradingview-webhooks-bot
But my broker is Oanda so I'm using python to place the trade. This link has more information.
https://github.com/hootnot/oanda-api-v20
The method is web hook->ngrok->python. When a web hook is sent, the ngrok (while script is also running) shows a 500 internal service error and that the server encountered an internal error and was unable to complete your request. Either the server is overloaded or there is an error in the application.
This is what my script says when its running (see picture);
First says some stuff related the market order then;
running script picture
One thing I noticed is that after Debug it doesn't say Running on... (so maybe my flask is not active?
Here is the python script;
from flask import Flask
import market_orders
# Create Flask object called app.
app = Flask(__name__)
# Create root to easily let us know its on/working.
#app.route('/')
def root():
return 'online'
#app.route('/webhook', methods=['POST'])
def webhook():
if request.method == 'POST':
# Parse the string data from tradingview into a python dict
print(market_orders.myfucn())
else:
print('do nothing')
if __name__ == '__main__':
app.run()
Let me know if there is any other information that would be helpful.
Thanks for your help.
I fixed it!!!! Google FTW
The first thing I learned was how to make my module a FLASK server. I followed these websites to figure this out;
This link helped me set up the flask file in a virtual environment. I also moved my Oanda modules to this new folder. And opened the ngrok app while in this folder via the command window. I also ran the module from within the command window using flask run.
https://topherpedersen.blog/2019/12/28/how-to-setup-a-new-flask-app-on-a-mac/
This link showed me how to set the FLASK_APP and the FLASK_ENV
Flask not displaying http address when I run it
Then I fixed the internal service error by adding return 'okay' after print(do nothing) in my script. This I learned from;
Flask Value error view function did not return a response

Creating an API to execute a python script

I have a python script app.py in my local server (path=Users/soubhik.b/Desktop) that generates a report and mails it to certain receivers. Instead of scheduling this script on my localhost, i want to create an API which can be accessed by the receivers such that they would get the mail if they hit the API with say a certain id.
With the below code i can create an API to display a certain text. But, what do i modify to run the script through this?
Also if i want to place the script in a server instead of localhost, how do i configure the same?
from flask import Flask
app = Flask(__name__)
#app.route("/")
def hello():
return ("hello world")
if __name__ == '__main__':
app.run(debug=True)
Python Version is 2.7
A good way to do this would be to put the script into a function, then import that function in your Flask API file and run it using that. For hosting on a web server you can use Python Anywhere if you are a beginner else heroku is also a good option.
If you are tying to achieve something using Python-Flask API than you can have a close look at this documentations and proceed further https://www.flaskapi.org/, http://flask.pocoo.org/docs/1.0/api/
Apart from these here are few basic examples and references you can refer for a quickstart :
1-https://programminghistorian.org/en/lessons/creating-apis-with-python-and-flask
2- https://flask-restful.readthedocs.io/en/latest/
3- https://realpython.com/flask-connexion-rest-api/
You could do something like this
from flask import Flask
from flask_restful import Resource, Api
app = Flask(__name__)
api = Api(app)
class ExecuteScript:
def printScript:
return "Hello World"
api.add_resource(ExecuteScript, '/printScript')
if __name__ == '__main__':
app.run(debug=True)

Cannot get API specs with Flask Blueprints and Swagger UI

So, following the examples for swagger ui usage with flask blueprints (https://github.com/rantav/flask-restful-swagger/blob/master/examples/blueprints.py), I have the following code:
app = Flask(__name__)
test_blueprint = Blueprint('tests', __name__)
test_api = swagger.docs(restful.Api(test_blueprint), apiVersion='0.1',
basePath='http://localhost:5000',
produces=["application/json", "text/html"],
api_spec_url='/api/spec')
# Operation TestOp defined here
test_api.add_resource(TestOp, '/')
if __name__ == "__main__":
app.register_blueprint(test_blueprint, url_prefix='/test')
app.run(debug=True)
However, when I try to access the api spec docs, the URL cannot be located.
I've tried...
localhost:5000/api/spec
localhost:5000/test_api/api/spec
localhost:5000/test_api
...all of which return a 404. I've also tried creating the app without blueprints, creating the docs with
swagger.docs(restful.Api(app)...)
instead. When there this is done and no blueprints are involved, I can reach the docs at
localhost:5000/api/spec
So, am I creating my application incorrectly with blueprints, or am I just not hitting the right URL to get access to the docs?
I know this thread is old, but I ran into this exact problem today, trying to use flask-restful-swagger with my (somewhat) modern flask + python3 app that uses blueprints. Same problem, no errors, just no spec available no matter what i tried.
I finally abandoned this package (as it seems like it hasn't been very active anyway), even though I like the markup better with this package.
I chose Flasgger, which seemed to be updated more recently. In 10 minutes I had it up and running. Code and short tutorial are here: https://github.com/rochacbruno/flasgger
It looks like you're just not hitting the right URL. Because your blueprint url_prefix is "/test", the Swagger spec url should be at:
localhost:5000/test/api/spec
something wrong in swagger.docs()
from flask_restful import Api
test_blueprint = Blueprint('tests', __name__)
test_api = swagger.docs(Api(test_blueprint)...)
app.register_blueprint(test_blueprint)
what'more
main_blueprint = Blueprint('api', __name__, url_prefix='/demo')

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