An RSVP Form

Part of the Forms section of Coddy's Django journey. Lesson 16 of 20.

Visitors want to say they are coming. The project has a new RSVP model with a ForeignKey to Event (related_name="rsvps"), and each event page has a form under the heading Coming?

The RSVP form asks for a name and an email, never for the event: the visitor is on that event's page, and a field would let them pick another. Leave the event out of fields, and set it in the view instead.

form.save(commit=False) builds the object without saving it, so you can set the rest first. A shop's order form never asks for the status:

form = OrderForm(request.POST)
if form.is_valid():
    order = form.save(commit=False)
    order.status = "new"
    order.save()

A plain form.save() stores the row at once, and a required ForeignKey left empty crashes with IntegrityError.

Challenge

Medium

Let visitors RSVP.

In events/forms.py, write a ModelForm RSVPForm for RSVP with only name and email.
In event_detail, pass an RSVPForm to the page as form. On a POST, build it from request.POST.
If valid, save with commit=False, set its event, save, add You're on the list! and redirect to the event. If not, show the form again.

RSVP to Friday Jazz Night: you see You're on the list!

Try it yourself

from django.contrib import messages
from django.shortcuts import get_object_or_404, redirect, render

from .forms import EventForm
from .models import Event


def event_list(request):
    q = request.GET.get("q", "")
    events = Event.objects.all()
    if q:
        events = events.filter(title__icontains=q)
    return render(request, "events/event_list.html", {"events": events, "q": q})


def event_detail(request, pk):
    event = get_object_or_404(Event, pk=pk)
    return render(request, "events/event_detail.html", {"event": event})


def new_event(request):
    if request.method == "POST":
        form = EventForm(request.POST)
        if form.is_valid():
            event = form.save()
            messages.success(request, "Your event was added.")
            return redirect("events:detail", pk=event.pk)
    else:
        form = EventForm()
    return render(request, "events/new_event.html", {"form": form})


def edit_event(request, pk):
    event = get_object_or_404(Event, pk=pk)
    if request.method == "POST":
        form = EventForm(request.POST, instance=event)
        if form.is_valid():
            form.save()
            messages.success(request, "Your changes were saved.")
            return redirect("events:detail", pk=event.pk)
    else:
        form = EventForm(instance=event)
    return render(request, "events/edit_event.html", {"form": form, "event": event})


def delete_event(request, pk):
    event = get_object_or_404(Event, pk=pk)
    if request.method == "POST":
        event.delete()
        messages.success(request, "The event was deleted.")
        return redirect("events:list")
    return render(request, "events/delete_event.html", {"event": event})