| revealOptions | ||
|---|---|---|
|
Create a virtualenv called smiles and install Django.
pew new --python=python3 smiles
pip install djangoCreate the "smiles" app template.
django-admin startproject --template=https://github.com/sloria/smiles/archive/template.zip smiles
cd smiles
cp .env.example .env
pip install -r requirements.txt
to
The client requests information from the server in different ways:
- HTTP Methods, e.g.
GET,POST - URL, e.g.
users/<username>/ - Query parameters, e.g.
/tweets/?year=2018 - Request body, e.g. form data
- Headers
The server returns responses back to the client with the following information:
- Status codes, e.g.
200,301,404 - Headers
- Response body
pip install httpie
http www.google.com
- How the Internet Works for Developers (2 videos)
Web sites: Static content; HTML/CSS/JS files only
Web applications: Dynamic content; HTML/CSS/JS on the frontend; Server-side languages (Python, Ruby, Node.js) on the backend
Server-side web frameworks
Frameworks solve common problems
- Routing: Connect a request to a URL to some Python code to execute
- Input handling: Parse HTTP requests into Python objects that are easy to interact with.
- Templating: Separate business logic from presentation code.
- Sessions: Associate data with a specific user (e.g. logged in/out)
- Database layer: Interact with a database using Python.
Create a virtualenv called smiles and install Django.
pew new --python=python3 smiles
pip install djangoCreate the "smiles" app template.
django-admin startproject --template=https://github.com/sloria/smiles/archive/template.zip smiles
cd smiles
cp .env.example .env
pip install -r requirements.txt.
├── main
│ ├── settings.py
│ ├── urls.py
│ ├── views.py
├── manage.py
├── requirements.txt
├── templates
├── hello.html
└── ...
In your smile directory, run
python manage.py runserverEnter http://localhost:8000 into your browser to view your app.
You define path patterns that will match the URLs entered in the browser. A match will trigger the execution of a view function.
Views are the Python functions that contain your application logic. They return the response data.
route = path pattern + view
/hello/ → hello(request)
Write this view.
# main/views.py
def hello(request):
return HttpResponse('Hello World')Add a new path pattern.
# main/urls.py
from . import views
urlpatterns = [
path('hello/', views.hello),
# ...
]Browse to
/hello/?name=Casey
request.GET is a dictionary containing the query parameters.
def hello(request):
name = request.GET.get('name', 'World')
return HttpResponse('Hello ' + name)
Browse to
http://localhost:8000/hello/?name=Casey
http://localhost:8000/hello/?name=Casey
Building HTML manually is pain.
def myview(request):
name = 'Casey'
return HttpResponse(
'<html>' +
'<body>' +
'<h1>' +
'Hello '+ name +
'</h1>' +
'</body>' +
'</html>'
)Separate data ("context") from HTML.
Context:
{'name': 'Casey'}
Template:
<html>
<body>
<h1>
Hello {{name}}
</h1>
</body>
</html>
# main/views.py
def hello(request):
name = request.GET.get('name', 'World')
# Templates are specified relative to the templates/ directory
return render(request, 'hello.html', context={'name': name}){# templates/hello.html #}
{# TODO: WRITE YOUR CODE BELOW #}
Hello {{name}}
{# END #}Browse to
http://localhost:8000/hello/?name=Casey
/coin/
Make a new route, /coin/, that uses the main.coin.flip function.
Render templates/coin.html with the word "Heads"
or "Tails" depending on the result of the flip.
The view has been started in main.views.coin_flip. Start there.
# main/views.py
from . import coin
def coin_flip(request):
result = coin.flip()
if result == 'H':
text = 'Heads'
else:
text = 'Tails'
return render(request, 'coin.html', context={'text': text})# main/urls.py
urlpatterns = [
# ...
path('coin/', views.coin_flip),
# ...
]{# templates/coin.html #}
<h1 class="f-6 tc code">
{{text}}
</h1>
{# templates/hello_with_form.html #}
<form method="POST" action="/hello_form">
<input name="name" /> {# <-- The data being sent #}
<input type="submit">
</form>request.POST is a dictionary of incoming form data.
# main/views.py
def hello_form(request):
if request.method == 'POST':
name = request.POST['name'] # <-- 'name' field from the form
else:
name = 'World'
context = {'name': name}
return render(request, 'hello_with_form.html', context=context)Modify the hello_form view to the following:
# main/views.py
def hello_form(request):
if request.method == 'POST':
name = request.POST['name'] # <-- 'name' field from the form
else:
name = 'World'
context = {'name': name}
return render(request, 'hello_with_form.html', context=context)Then hook up hello2/ to the hello_form view in main/urls.py.
# main/urls.py
urlpatterns = [
# ...
path('hello2/', views.hello_form),
# ...
]
If you try to refresh the page...
The redirect() call will send a 302 redirect back to /hello2/
# main/views.py
def hello_form(request):
if request.method == 'POST':
name = request.POST['name']
return redirect('/hello2/?name=' + name)
else:
name = request.GET.get('name', 'World')
return render(request, 'hello_with_form.html', context={'name': name})
Before you close your Terminal, don't
Before you close your terminal, don't forget to shut down your
development server using ctrl-c.