Passing variable through response object in Flask framework - html

Question

I need to pass a variable along with response object while complete signup process and display the success message on the same page. I tried so many ways but I couldn't find any idea how to do that. Please look at this scenario and help me out.
#app.route('/signup', methods=['POST', 'GET'])
def signup():
message = ''
email = ''
password = ''
resp = app.make_response(render_template('signup.html'))
if request.method == 'POST':
import datetime
email = request.form['emailInput']
password = request.form['pswdInput']
if len(password) < 3:
message = Markup("<p style='color:red;'> Password Length Should Be More Than 3 Character </p> ")
return render_template('signup.html', message = message)
expire_date = datetime.datetime.now()
expire_date = expire_date + datetime.timedelta(hours=1)
resp.set_cookie('userEmail', email, expires=expire_date)
resp.set_cookie('userPassword', password, expires=expire_date)
message = Markup("<h1> Registration successfull! </h1>")
resp.headers.set('message', message)
return resp
return render_template('signup.html', message = message)
HTML :
<div class="container">
Home
<form id="signup" method="POST" action="{{url_for('signup')}}">
<div class="header">
<h3>Sign Up</h3>
<p>You want to fill out this form</p>
</div>
<div class="sep"></div>
<div class="">
<input type="email" name="emailInput" placeholder="e-mail" autofocus />
<input type="password" name="pswdInput" placeholder="Password" />
<div class="">
<input name="joinCheck" name="joinCheck" value="1" type="checkbox" /><label class="terms">I accept the terms of use</label>
</div>
<input type="submit" id="submitBtn" value="Submit">SIGN UP FOR INVITE NOW</a>
</div>
<div>
{{message}}
</div>
</form>
</div>

Answer 1

resp = app.make_response(render_template('signup.html'))
This is missing your message keyword. Change it to:
resp = app.make_response(render_template('signup.html', message=message))
You need to move this code down also, because to it, it sees the message variable directly above as the empty string and assigns that to its keyword. I would place it right above your resp.set_cookie() code.
Finally, move this:
message = Markup("<h1> Registration successfull! </h1>")
Above the app.make_response() code you just moved. Your message variable needs to be set before the response code is initialized.
Just a small tip: I would change message = " " to message = None. Otherwise, in the compiled HTML, it just looks like there's an empty div. This won't be too detrimental in this small case, but I'd definitely make it a rule of thumb in future, larger projects. Then, in your HTML:
{% if message %}
<div>
{{message}}
</div>
{% endif %}
Cheers.