Heroku - Python simple POST api, only can do GET (cannot do POST) - python

I want to do a web API which consist only POST. Currently I need to run python script on the web, so I am building a python web server from flask in Heroku. However, my issue is, whenever I send POST request from POSTMAN, what I will receive is the return data which is actually from GET request. Below is my code:
from flask import Flask
from flask import request
import os
app = Flask(__name__)
#app.route("/", methods=['GET', 'POST'])
def api_grab_key():
if request.method == 'POST':
if request.headers['Content-Type'] == 'application/json':
return request.json["imgUrl"]
else:
return "Request must be in JSON"
if request.method == 'GET':
return "Hello World! GET request"
if __name__ == "__main__":
port = int(os.environ.get('PORT', 33507))
app.run(host='0.0.0.0', port=port)
It works when I run locally, but not on Heroku. On Heroku, the output is always "Hello World! GET request" Thanks!

Sorry, apparently my issue is in the URL. So in Heroku, it has xxx.heroku.com and xxx.herokuapp.com.
I don't know why, requests sent to xxx.heroku.com turns into GET request. So, I had to change it to xxx.herokuapp.com for POST request.

I don't see anything jumping out, have you tried enabling debugging mode in Flask?
app.run(debug=True)
Then:
heroku logs --tail

Related

redirect a POST to GET request

I'm trying to understand what is the best way a POST request can be redirected to a GET request.
for example -
POST /redirect HTTP/1.1
Host: www.example1.com
url=www.example2.com
and i've created the following flask to help me with that :
from flask import Flask,request, redirect
app = Flask(__name__)
#app.route('/redirect',methods=['POST'])
def redire():
url = request.form['url']
return redirect('https://www.example2.com', code=307)
if __name__ == '__main__':
app.run(host='0.0.0.0', port=8888)
the "issue" in my case, is that the request that is being sent to
https://www.example2.com
is also a POST request which is not what i wanted.
Consider that I don't "care" about the body that needs to be sent to the
https://www.example2.com
endpoint, what is the best way to do so without any user intervention (meaning that I'm aiming for an auto redirect).
Note: I've tried to do it via PHP but I can't seem to figure it out.
Apologies if something is not clear.
In order to redirect a POST request to a GET request, you need to use code=303 because it requires the client to use the GET method to retrieve the requested resource.
#app.route('/redirect',methods=['POST'])
def redire():
url = request.form['url']
return redirect('https://www.example2.com', code=303)
the server
from flask import Flask, redirect
app = Flask(__name__)
#app.route('/redirect', methods=['POST'])
def redire():
return redirect('http://127.0.0.1:8888/get')
#app.route('/get', methods=['GET'])
def iam_get():
return {"code": "ok"}
if __name__ == '__main__':
app.run(host='0.0.0.0', port=8888)
the client
import requests
data = requests.get("http://127.0.0.1:8888/get")
print(data.text)
data = requests.post("http://127.0.0.1:8888/redirect")
print(data.text)
the result as follows
{"code":"ok"}
{"code":"ok"}

IIS returning 500 Internal Server Error for POST but working for GET- Flask

I am facing an issue with my flask program.
I hosted a flask application on IIS running on Win 11. But from Postman I am Getting Get response but 500 error when Methos = POST.
But there is no error when running the same code from VS Code.
My Flask code:
import decodedata
import Call_printer
from flask import Flask, request, render_template,jsonify
app = Flask(__name__)
#app.route('/print',methods = ['GET','POST'])
def printer():
if request.method == 'POST':
req_data = request.json
print(req_data)
data = req_data['data']
printername= req_data['printername']
xml = decodedata.decode_xml(data)
msg = Call_printer.sendprintjob(printername,xml)
status={"Status":msg}
return jsonify(status)
if request.method == 'GET':
return "Hello World."
if __name__ == '__main__':
app.debug = True
app.run()
Below is an error when running from IIS.
Error in IIS
Below is the correct POST Response from VS CODE
Success in VS Code
But I am receiving responses in GET method from IIS. Only for POST, I am receiving 500 error?
Can it be because I am calling other py files for POST?
Any idea how can I fix it?
Regards,
Mayank Pande

I can't run the Python Flask application, help needed

When I run this Flask application logs in console seem to be fine, but I cannot find my webpage by the default url.
Error: Not Found
The requested URL was not found on the server. If you entered the URL manually please check your spelling and try again. I entered this URL : http://127.0.0.1:5000/ with the trailing slash.
Any thoughts?
from flask import Flask
app = Flask(__name__)
#app.route('/')
def home():
return "Hello, World! <h1>Hello, World!<h1>"
if __name__ == '__main__':
app.run(debug = False)
The error webpage looks like this
As you can see in the screenshot, the webserver is running. Just go to your browser and type in the search bar:
localhost:5000

Python flask error code 400, message Bad request version

The code of the website
from flask import *
app = Flask(__name__)
#app.route("/<name>")
def user(name):
return f"Hello {name}!"
#app.route("/")
def home():
return render_template("index.html")
#app.route("/admin")
def admin():
return redirect(url_for("home"))
if __name__ == "__main__":
app.run()
If I go to http://127.0.0.1:5000/ there are not issues but when I go to https://127.0.0.1:5000/ (https not http this time) I get the following error
127.0.0.1 - - [17/Nov/2019 17:43:25] code 400, message Bad request version ('y\x03Ðã\x80¨R¾3\x8eܽ\x90Ïñ\x95®¢Ò\x97\x90<Ù¦\x00$\x13\x01\x13\x03\x13\x02À+À/̨̩À,À0À')
The error code 400, message Bad request version is basically what I expected since I have not set up SSL nor have I declared what the website should do when getting a https request. What I am curious to find out is what the weird symbols mean (y\x03Ð.... and so on). This goes out to multiple questions such as: Where do they come from? Have the python code attempted to access a random memory location with no specific data? Is the data just in a format that the console cannot handle? What does it mean? You get the idea.
You're missing the ssl_context in app.run() which configures Flask to run with HTTPS support.
See the this article about it
If this is just for testing, you can use adhoc mode.
if __name__ == "__main__":
app.run(ssl_context="adhoc")

Python, Flask, 'Hello World': No browser reaction

I have pip-installed Flask and HTML5 on my Window-system. When I start the Hello World!-program with IDLE, I get a red message in the Python-Shell:
"* Running on xxxx://127.0.0.1:5000/". (xxxx = http)
And when I start it with app.run(debug=True) another red message appears:
"* Restarting with reloader".
My browser (Firefox) shows no reaction.
What can I do to get 'Hello World' in a new tab of Firefox?
The Code is:
from flask import Flask
app = Flask(__name__)
#app.route("/")
def hello():
return "Hello World!"
if __name__ == "__main__":
app.run(debug=True)
return and app.run are indended
You have to open a new tab with this url:
http://127.0.0.1:5000/
You need to actually open the page in your browser - it won't open itself. Open Firefox and navigate to
127.0.0.1:5000
(it's a URL)
When you run your code, it sits around waiting for a request from the user. When it gets a request, it'll return a response, and that's (sort of) what you see in your browser. Going to a URL is how you send that request - Flask will interpret anything sent to 127.0.0.1:5000 as a request, and try to match the URL to one of your #app.route decorators. For example, if you were to have a function decorated with #app.route("/hello"), then when you go to 127.0.0.1:5000/hello, Flask would run that function to determine the response.
Try out this code:
from flask import Flask
app = Flask(__name__)
#app.route("/")
def index():
return "<h1>Hello!</h1>"
if __name__ == "__main__":
from waitress import serve
serve(app, host="0.0.0.0", port=8080)
refrence Flask at first run: Do not use the development server in a production environment
from flask import Flask
app = Flask(__name__)
#app.route("/")
def hello():
return "Hello World!"
if __name__ == "__main__":
app.run(debug=True)
Try this, this works for me. Open your firefox browser and go to the address given in the output. ex: http://XXXX.X.X.X:5000/

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