code-boxx/0-PY-CSRF.MD

## 0-PY-CSRF.MD

      
    Raw
  

              0-PY-CSRF.MD
            
          
    SIMPLE PYTHON FLASK CSRF

https://code-boxx.com/simple-python-flask-csrf/
NOTES


Run unpack.bat (Windows) unpack.sh (Linux/Mac). This will automatically:

Create a static and templates folder.
Move css js files into the static folder.
Move html files into the templates folder
Create a virtual environment - virtualenv venv.
Activate the virtual environment - venv\scripts\activate (Windows) venv/bin/activate (Mac/Linux)
Install required modules - pip install flask pyjwt bcrypt
Run python 2-server.py to start the server.


Access http://localhost in your browser, submit the dummy form.

LICENSE

Copyright by Code Boxx
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

  
## 1-form.html
<!DOCTYPE html>
<html>
  <head>
    <title>Dummy Form</title>
    <link rel="stylesheet" href="static/x-dummy.css">
  </head>
  <body>
    <form method="post" action="go" target="_blank">
      <!-- (A) HIDDEN HTML TOKEN -->
      <div>* This token should be hidden in your actual project</div>
      <input type="text" name="token" value="{{ token }}">

      <!-- (B) FIELDS AS USUAL -->
      <input type="email" required name="email" value="jon@doe.com">
      <input type="submit" value="GO">
    </form>
  </body>
</html>

## 2-server.py
# (A) INITIALIZE
# (A1) LOAD MODULES
from flask import Flask, request, session, render_template
import random, string

# (A2) FLASK INIT
app = Flask(__name__)
app.secret_key = "YOUR_SECRET_KEY"
# app.debug = True

# (A3) SETTINGS
HOST_NAME = "localhost"
HOST_PORT = 80
CSRF_CHAR = 12

# (B) ROUTES
# (B1) DUMMY HTML FORM
@app.route("/")
def index():
  session["token"] = "".join(random.choices(string.ascii_uppercase, k=CSRF_CHAR))
  return render_template("1-form.html", token=session["token"])

# (B2) SUBMIT FORM
@app.route("/go", methods=["POST"])
def go():
  # (B2-1) TOKEN IS NOT "PRIMED"
  if ("token" not in session or request.form.get("token") is None):
    return "Token mismatch"

  # (B2-2) CHECK SUBMITTED TOKEN VS SESSION
  if (request.form.get("token") == session["token"]):
    # OK - DO YOUR PROCESSING
    # REMOVE TOKEN AFTER PROCESSING?
    # session.pop("token")
    return "It works!"
  else:
    return "Token mismatch"

# (C) START!
if __name__ == "__main__":
  app.run(HOST_NAME, HOST_PORT)

## unpack.bat
md static
md templates
move 1-form.html templates
move x-dummy.css static
virtualenv venv
call venv\Scripts\activate
pip install flask
python 2-server.py

## unpack.sh
mkdir -m 777 static
mkdir -m 777 templates
mv ./1-form.html ./templates
mv ./x-dummy.css ./static
virtualenv venv
source "venv/Scripts/activate"
pip install flask
python 2-server.py

## x-dummy.css
* {
  font-family: Arial, Helvetica, sans-serif;
  box-sizing: border-box;
}
form {
  max-width: 500px;
  margin: 0 auto;
  padding: 20px;
  background: #fafafa;
  border: 1px solid #ebebeb;
}
input {
  width: 100%;
  padding: 10px;
}
input[type=text], input[type=email] {
  margin-top: 10px;
  border: 1px solid #d7d7d7;
}
input[type=submit] {
  font-weight: 700;
  border: 0;
  margin-top: 10px;
  color: #fff;
  background: #bb1b1b;
  cursor: pointer;
}
	<!DOCTYPE html>
	<html>
	<head>
	<title>Dummy Form</title>
	<link rel="stylesheet" href="static/x-dummy.css">
	</head>
	<body>
	<form method="post" action="go" target="_blank">
	<!-- (A) HIDDEN HTML TOKEN -->
	<div>* This token should be hidden in your actual project</div>
	<input type="text" name="token" value="{{ token }}">

	<!-- (B) FIELDS AS USUAL -->
	<input type="email" required name="email" value="jon@doe.com">
	<input type="submit" value="GO">
	</form>
	</body>
	</html>
	# (A) INITIALIZE
	# (A1) LOAD MODULES
	from flask import Flask, request, session, render_template
	import random, string

	# (A2) FLASK INIT
	app = Flask(__name__)
	app.secret_key = "YOUR_SECRET_KEY"
	# app.debug = True

	# (A3) SETTINGS
	HOST_NAME = "localhost"
	HOST_PORT = 80
	CSRF_CHAR = 12

	# (B) ROUTES
	# (B1) DUMMY HTML FORM
	@app.route("/")
	def index():
	session["token"] = "".join(random.choices(string.ascii_uppercase, k=CSRF_CHAR))
	return render_template("1-form.html", token=session["token"])

	# (B2) SUBMIT FORM
	@app.route("/go", methods=["POST"])
	def go():
	# (B2-1) TOKEN IS NOT "PRIMED"
	if ("token" not in session or request.form.get("token") is None):
	return "Token mismatch"

	# (B2-2) CHECK SUBMITTED TOKEN VS SESSION
	if (request.form.get("token") == session["token"]):
	# OK - DO YOUR PROCESSING
	# REMOVE TOKEN AFTER PROCESSING?
	# session.pop("token")
	return "It works!"
	else:
	return "Token mismatch"

	# (C) START!
	if __name__ == "__main__":
	app.run(HOST_NAME, HOST_PORT)
	md static
	md templates
	move 1-form.html templates
	move x-dummy.css static
	virtualenv venv
	call venv\Scripts\activate
	pip install flask
	python 2-server.py
	mkdir -m 777 static
	mkdir -m 777 templates
	mv ./1-form.html ./templates
	mv ./x-dummy.css ./static
	virtualenv venv
	source "venv/Scripts/activate"
	pip install flask
	python 2-server.py
	* {
	font-family: Arial, Helvetica, sans-serif;
	box-sizing: border-box;
	}
	form {
	max-width: 500px;
	margin: 0 auto;
	padding: 20px;
	background: #fafafa;
	border: 1px solid #ebebeb;
	}
	input {
	width: 100%;
	padding: 10px;
	}
	input[type=text], input[type=email] {
	margin-top: 10px;
	border: 1px solid #d7d7d7;
	}
	input[type=submit] {
	font-weight: 700;
	border: 0;
	margin-top: 10px;
	color: #fff;
	background: #bb1b1b;
	cursor: pointer;
	}