How to assign a function to a button in Django Python

Question

I am doing a Jango course and I would like to know if it is possible to assign a function to a button.

For example:

  <form>
      <label for="word">Digite uma palavra:</label>
      <input id="word" type="text" name="palavra" value="" />
      <input type="submit">                   
  </form>

In this search bar the user would type any word. The moment this user clicked send I would like a function that I called 'Tamanho_da_str' to be executed:

def tamanho_da_str(request):
    palavra_digitada = **Palavra que o usuário digitou na barra de pesquisa**
    len_string = len(palavradigitada)
    dicionario = {'tamanho': len_string}
    return render(request, "resultado.html", dicionario)

For this to work I would need to establish a link between the send button and the function size_da_str, then I would need the word typed by the user to be stored in the typed word variable.

Can you tell me if this is possible and what methods are used ?

Ps : Maybe because I’m not a developer and I don’t know some terms related to the area I couldn’t find anything on the internet, but any direction will be welcome.

Answer 1

Since you are already programming in Django, you probably already know, but I’ll make it clear here: Django is called the MTV framework (Model-Template-View). The view (view) part usually inspects the incoming HTTP request and queries or processes the data to be rendered (presentation).

I will present here an example that Voce can run on your command line, to simplify put the example in just two files, but this is not the usual practice in the world of Jango development, I make some comments on the code (the ones I remembered) explaining what would be the convention adopted by the community, come on:

File: main.py

# Configurações do django, aqui configura-se o projeto django, desde conexoes 
# com banco de dados até recursos estaticos e funcionalidades de internacionalização
# Normalmente, no 'mundo real', essas configuracoes estariam em um arquivo settings.py
from django.conf import settings
import os
ROOT = os.path.dirname(os.path.abspath(__file__))
settings.configure(
    DEBUG=True,
    SECRET_KEY = '0uarl&=3a$o1*0wk-5s@x6@d*0%r576h0&@f65+09ebtkv3jtd',
    ROOT_URLCONF=__name__,
    MIDDLEWARE = (
        'django.middleware.common.CommonMiddleware',
        'django.middleware.csrf.CsrfViewMiddleware',
        'django.middleware.clickjacking.XFrameOptionsMiddleware',
    ),
    TEMPLATES = [
        {
            'BACKEND': 'django.template.backends.django.DjangoTemplates',
            'DIRS': [ROOT]
        }
    ]
)

# No mundo real esse codigo estaria em um arquivo views.py
from django.http import HttpResponse
from django.shortcuts import render 
def index(request):

    count = None
    palavra = None

    if request.method=='POST':
        palavra = request.POST['palavra']
        count = len(palavra)

    return render(request, 'palavra.html', {'count': count, 'palavra': palavra})

# Para conectar a view à estrutura do site é preciso associa-la a uma URL
# No mundo real esse codigo estaria em um arquivo urls.py
from django.urls import include, path
urlpatterns = (
    path('', index),
)


if __name__ == "__main__":
    import sys
    from django.core.management import execute_from_command_line
    execute_from_command_line(sys.argv)

File: word.html

<form method="POST">
    {% csrf_token %}
    <label for="word">Digite uma palavra:</label>
    <input id="word" type="text" name="palavra" value="" />
    <input type="submit"> 
    {% if count != None %}
        <br><br>
        Palavra digitada: {{palavra}}<br>
        Número de caracteres: {{count}}
    {% endif %}
</form>

Now run on your command line:

$ python main.py runserver

And you will get:

Performing system checks...

System check identified no issues (0 silenced).
February 14, 2019 - 11:55:14
Django version 2.1.1, using settings None
Starting development server at http://127.0.0.1:8000/
Quit the server with CONTROL-C.

On your Rowse, point to http://127.0.0.1:8000/ and you’ll get:

Type for example the word "stackoverflow"

And you will get:

Answer 2

Hello, Voce uses the POST method and so Django recognizes HTML by the attribute name

 <form method = 'POST'>
       {% csrf_token %}
      <label for="word">Digite uma palavra:</label>
      <input id="word" type="text" name="palavra" value="" />
      <input type="submit">                   
  </form>

use the request

def tamanho_da_str(request):

if request.method == 'POST':     
 palavra_digitada = request.POST.get('palavra')
 print (palavra_digitada)
 ....

I hope I’ve helped,

And may the force be with you