Django credit card redaction app - - MultiValueDictKeyError
drone4four
Hello!
I’m trying to run a basic Django app which redacts a 16 digit number entered by the user. I had a it running a few minutes ago. I’m not sure what I changed, but now I am getting a MultiValueDictKeyError. I’ve triple checked every variable. The only dictionary in my project is in views.py at line 7. As far as I can tell, it’s all accurate and positioned correctly. I don’t recall changing this dictionary or any other operator around this line. I’m stumped. What would you people suggest? Have a look at my setup.
Here is the error and traceback in full: https://pastebin.com/QwSrmAJx
Here is my urls.py:
from django.conf.urls import include, url
from django.contrib import admin
from django.urls import path
from . import views
urlpatterns = [
url(r'^admin/', admin.site.urls),
url(r'^$', views.home, name='home'),views.py:
from django.http import HttpResponse
from django.shortcuts import render
def home(request):
number = request.GET['ccEntry']
redacted_num = 'xxxx xxxx xxxx {}'.format(number[-4:])
return render(request, 'home.html', {'number':number, 'redacted_num':redacted_num})home.html template:
<style></style>
<center>
<form action="{% url 'home' %}">
<div> <br> <br> <br> <br>
<h3>Enter your fake Chuckee Cheese Neptune credit card number!</h3>
<input type="number" id="number" name="ccEntry" required placeholder=" " pattern=".{16,16}"/>
<br>
<br>
<div class="requirements">
Must be a 16 digit number.
</div>
<br>
<input type="submit" value="Redact!!!"/>
</div>
</form>
<br>
<h3>Original Card Number:</h3>
<br>
{{ number }}
<br>
<h3>Redacted Card Number:</h3>
<br>
{{ redacted_num }}
<br>
<h3> Did this work?</h3>
<br>
</center>
Sam Taiwo
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drone4four
Thanks, Sam for the help.
You wrote:
I would be careful how you pass the data on get, somewhere in your front end code you are probably not passing the data through as you expected. Instead of using .GET, use .GET.get to get your data. This will either return the value you want, or none.
I looked up GET.get Django and found an SO post titled, “Django request.GET” which has quite a few up votes. Based on that SO answer, In my views.py I changed the line (where I declare the number variable) from `number = request.GET['ccEntry']` to `number = request.GET.get['ccEntry', None]`
That gives a different error (a type error this time): https://pastebin.com/L81LVtzi
You also mentioned my front end. I had included the template in my original post. I have since refined it so it is more readable. Here is my improved home.html template:
<html>
<head>
<title> Search </title>
</head>
<body>
<center>
<form action="{% url 'home' %}">
<div>
<h3>Enter your fake Chuckee Cheese Neptune credit card number!</h3>
<input type="number" id="number" name="ccEntry" required placeholder=" " pattern=".{16,16}"/>
<div class="requirements"> Must be a 16 digit number. </div>
<input type="submit" value="Redact!!!"/>
</div>
</form>
<h3>Original Card Number:</h3>
{{ number }}
<h3>Redacted Card Number:</h3>
{{ redacted_num }}
<h3> Did this work?</h3>
</center>
</body>
</html>Sam, you also suggested:
I think you have made the error of not passing your data to the get header as you didn't explicitly write this on the form element.
I did explicitly include my data in my form element as you can see in the above template.
Check the URL and log the get object in Django to make sure the data is actually appearing in both.
The data is present as “ccEntry” in both home.html and in views.py.
Matthew Pava
Please just paste the error in the email message. The error message that you have mentions a ‘method’ object, which is not present in the code that you have sent to us. That would be where the problem is.
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drone4four
MultiValueDictKeyError at /
'ccEntry'
| Request Method: | GET |
|---|---|
| Request URL: | http://127.0.0.1:8000/ |
| Django Version: | 2.0.2 |
| Exception Type: | MultiValueDictKeyError |
| Exception Value: | 'ccEntry' |
| Exception Location: | /home/<user>/.local/lib/python3.7/site-packages/django/utils/datastructures.py in __getitem__, line 79 |
| Python Executable: | /usr/sbin/python |
| Python Version: | 3.7.2 |
| Python Path: | ['/home/<user>/dev/projects/python/2018-and-2019/cel2fah-original_with_CC-redact-project-_Django202/first_project_attempt', '/usr/lib/python37.zip', '/usr/lib/python3.7', '/usr/lib/python3.7/lib-dynload', '/home/<user>/.local/lib/python3.7/site-packages', '/usr/lib/python3.7/site-packages', '/usr/lib/python3.7/site-packages/setuptools-40.6.2-py3.7.egg'] |
| Server time: | Thu, 7 Mar 2019 17:39:40 +0000 |
Request information
USER
AnonymousUser
GET
No GET data
POST
No POST data
FILES
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Deepak Chhitarka
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drone4four
I am taking a course on Udemy and the instructor doesn’t include a method attribute in the form tag. But as you suggested, Deepak, I went ahead and added method="get" to my form tag in my home.html template. So line 7 now reads: <form action="{% url 'home' %}" method="get">
I am still encountering the MultiValueDictKeyError.
Here is the traceback again:
MultiValueDictKeyError at /
'ccEntry'
Request Method: GET
Request URL: http://127.0.0.1:8000/
Django Version: 2.0.2
Exception Type: MultiValueDictKeyError
Exception Value:
'ccEntry'
Exception Location: /home/<user>/.local/lib/python3.7/site-packages/django/utils/datastructures.py in __getitem__, line 79
Python Executable: /usr/sbin/python
Python Version: 3.7.2
Python Path:
['/home/<user>/dev/projects/python/2018-and-2019/cel2fah-original_with_CC-redact-project-_Django202/first_project_attempt',
'/usr/lib/python37.zip',
'/usr/lib/python3.7',
'/usr/lib/python3.7/lib-dynload',
'/home/<user>/.local/lib/python3.7/site-packages',
'/usr/lib/python3.7/site-packages',
'/usr/lib/python3.7/site-packages/setuptools-40.6.2-py3.7.egg']
Server time: Thu, 7 Mar 2019 20:11:44 +0000
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drone4four
This is a long shot, but I thought I would share a link to my source code hosted on GitHub with a requirements.txt included. If any of you would like to test this out yourself, I am accepting pull requests. Here it is: https://github.com/Angeles4four/CC_Redact
drone4four
I’ve discovered a ‘hack’ to correct the issue. I committed and pushed my changes up to my GitHub repo for those curious enough to try it out yourself.
My problem now is that I don’t really understand why it works. Here I will explain what I do know and then my ask would be for you people to fill in the gaps in my explanation. First I share my working code.
Here is my views.py which includes the relevant function I use:
from django.http import HttpResponse
from django.shortcuts import render
def home(request):
if 'ccEntry' in request.GET:
number = request.GET['ccEntry']
redacted_num = 'xxxx xxxx xxxx {}'.format(number[-4:])
return render(request, 'home.html', {'number':number, 'redacted_num':redacted_num})
else:
return render(request, 'home.html')Here is my lucid, cerebral explanation of the above Python code in plain English: At line 4 I am defining the `home` function. Then there is a conditional referring to the ‘ccEntry’ string inside the template. If ccEntry is present in the GET request, then a `number` variable is declared based on the user input on the web page. Then a `redacted_num` variable is declared which will appear as a string (‘xxxx xxxx xxxx ’ with the last 4 characters lopped off (the slice). If all of the above is in order, then the render function will be returned:
with the standard request,
with reference to the home.html template,
along with a dictionary with a ‘number’ string matching up with the `number` variable. Ditto for the redact_num.
However if the above condition is false, then the render function will return the standard request and home.html template without a dictionary. That’s pretty much everything I understand.
I’m not sure why a conditional as it appears above is necessary.
Would someone here care to explain, if you can?
Ahmed Ishtiaque
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drone4four
Thank you Ahmed for this clarification. This makes sense.
I have two further questions for you (or anyone else still reading this thread):
Is there a way of checking for the presence of the data with GET which is more Pythonic and aligns with better practices?
On an unrelated note, I attempted to reduce my issue in this testcase as best I could. I think I did an OK job. But would there be a better way for me to ask my question to attract more responses? What would any of you recommend in terms of advice for me to refine and refine the way I ask similar questions in the future on this message board?
Ahmed Ishtiaque
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