Thank you Ahmed for this clarification. This makes sense.
I have two further questions for you (or anyone else still reading this
thread):
1.
Is there a way of checking for the presence of the data with GET which
is more Pythonic and aligns with better practices?
1.
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?
On Thursday, March 14, 2019 at 2:13:35 PM UTC-4, Ahmed Ishtiaque wrote:
>
> When a user requests your home page's URL the first time in order to load
> your home.html file, the GET request they send to your server does not
> contain the 'ccEntry' parameter, which raised the MultiValueDictKeyError
> whenever your view was executing. However, in your edited view, you take
> care of that by first checking whether the GET request contains 'ccEntry',
> which is why it is working correctly now.
>
> On Thu, Mar 14, 2019 at 9:57 AM drone4four <drone...@gmail.com
> <javascript:>> wrote:
>
>> 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?
>>
>>
>> On Thursday, March 7, 2019 at 4:05:28 PM UTC-5, drone4four wrote:
>>>
>>> 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
>>>
>>>
>>> On Thursday, March 7, 2019 at 4:03:37 PM UTC-5, drone4four wrote:
>>>>
>>>> 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
>>>>
>>>> Environment:
>>>>
>>>>
>>>> Request Method: GET
>>>>
>>>> Request URL: http://127.0.0.1:8000/
>>>>
>>>> Django Version: 2.0.2
>>>>
>>>> Python Version: 3.7.2
>>>>
>>>> Installed Applications:
>>>>
>>>> ['django.contrib.admin',
>>>>
>>>> 'django.contrib.auth',
>>>>
>>>> 'django.contrib.contenttypes',
>>>>
>>>> 'django.contrib.sessions',
>>>>
>>>> 'django.contrib.messages',
>>>>
>>>> 'django.contrib.staticfiles']
>>>>
>>>> Installed Middleware:
>>>>
>>>> ['django.middleware.security.SecurityMiddleware',
>>>>
>>>> 'django.contrib.sessions.middleware.SessionMiddleware',
>>>>
>>>> 'django.middleware.common.CommonMiddleware',
>>>>
>>>> 'django.middleware.csrf.CsrfViewMiddleware',
>>>>
>>>> 'django.contrib.auth.middleware.AuthenticationMiddleware',
>>>>
>>>> 'django.contrib.messages.middleware.MessageMiddleware',
>>>>
>>>> 'django.middleware.clickjacking.XFrameOptionsMiddleware']
>>>>
>>>>
>>>>
>>>> Traceback:
>>>>
>>>> File
>>>> "/home/<user>/.local/lib/python3.7/site-packages/django/utils/datastructures.py"
>>>>
>>>> in __getitem__
>>>>
>>>> 77. list_ = super().__getitem__(key)
>>>>
>>>> During handling of the above exception ('ccEntry'), another exception
>>>> occurred:
>>>>
>>>> File
>>>> "/home/<user>/.local/lib/python3.7/site-packages/django/core/handlers/exception.py"
>>>>
>>>> in inner
>>>>
>>>> 35. response = get_response(request)
>>>>
>>>> File
>>>> "/home/<user>/.local/lib/python3.7/site-packages/django/core/handlers/base.py"
>>>>
>>>> in _get_response
>>>>
>>>> 128. response =
>>>> self.process_exception_by_middleware(e, request)
>>>>
>>>> File
>>>> "/home/<user>/.local/lib/python3.7/site-packages/django/core/handlers/base.py"
>>>>
>>>> in _get_response
>>>>
>>>> 126. response = wrapped_callback(request,
>>>> *callback_args, **callback_kwargs)
>>>>
>>>> File
>>>> "/home/<user>/dev/projects/python/2018-and-2019/cel2fah-original_with_CC-redact-project-_Django202/first_project_attempt/first_project_attempt/views.py"
>>>>
>>>> in home
>>>>
>>>> 5. number = request.GET['ccEntry']
>>>>
>>>> File
>>>> "/home/<user>/.local/lib/python3.7/site-packages/django/utils/datastructures.py"
>>>>
>>>> in __getitem__
>>>>
>>>> 79. raise MultiValueDictKeyError(key)
>>>>
>>>> Exception Type: MultiValueDictKeyError at /
>>>>
>>>> Exception Value: 'ccEntry'
>>>>
>>>>
>>>> Request information
>>>>
>>>> USER
>>>>
>>>> AnonymousUser
>>>>
>>>> GET
>>>>
>>>> No GET data
>>>>
>>>> POST
>>>>
>>>> No POST data
>>>>
>>>> FILES
>>>>
>>>> No FILES data
>>>>
>>>>
>>>> On Thursday, March 7, 2019 at 2:50:00 PM UTC-5, Deepak Chhitarka wrote:
>>>>>
>>>>> In your home.html template, you forgot to write method="get" . Which I
>>>>> think is causing the problem here.
>>>>>
>>>>> On Fri 8 Mar, 2019, 12:03 AM Matthew Pava, <matthe...@iss.com> wrote:
>>>>>
>>>>>> 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.
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> *From:* django...@googlegroups.com [mailto:django...@googlegroups.com]
>>>>>> *On Behalf Of *drone4four
>>>>>> *Sent:* Thursday, March 7, 2019 11:29 AM
>>>>>> *To:* Django users
>>>>>> *Subject:* Re: Django credit card redaction app - -
>>>>>> MultiValueDictKeyError
>>>>>>
>>>>>>
>>>>>>
>>>>>> 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
>>>>>> <https://stackoverflow.com/questions/3500859/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="
>>>>>>
>>>>> --
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