Django表单工作原理及action属性与HttpResponseRedirect疑问

Hey JohnB, let’s break down how these two pieces work together— I’ve wrestled with this exact confusion when I was learning Django, so I get where you’re coming from.

First: The <form> action Attribute #

This isn’t even Django-specific—it’s core HTML! The action tells your browser where to send the form data when the user clicks "Submit".

• In your case, you’ve set action to play_outcomes/output, so when someone submits the form, their browser sends a POST request (by default, unless you specify method="GET") to that URL path.
• If you leave action empty (like <form method="POST">), the form will submit back to the same URL that rendered it—so in your scenario, that’d be play_outcomes/getinput.
• Pro tip in Django: Instead of hardcoding the path, use the {% url %} template tag to reference your URL pattern name (e.g., action="{% url 'play_outcomes:output' %}"). This avoids broken links if you ever change your URL paths later.

Next: HttpResponseRedirect in Views #

Once your form data hits the view tied to play_outcomes/output, you’ll process it (validate via your forms.py class, save data, etc.). Then comes HttpResponseRedirect—this is Django’s way of telling the browser to navigate to a new URL after processing the form.

Why is this important? It’s part of the Post/Redirect/Get (PRG) pattern, which solves a common problem:

• If you just return a template directly from your POST view, the user hitting "Refresh" would resend the POST request (and re-submit the form!).
• By redirecting, you send the browser a GET request to the new URL—so refreshing only reloads that GET page, no duplicate form submissions.

Example Flow for Your Setup #

1. User visits play_outcomes/getinput (GET request) → your view renders the form template.
2. User fills out the form, clicks Submit → browser sends POST data to play_outcomes/output (as specified by action).
3. Your output view validates the form data, does whatever processing you need (save to DB, calculate results, etc.).
4. Instead of returning a template directly, you use HttpResponseRedirect to send the user to a results page (e.g., play_outcomes/results).
5. The browser loads the results page via GET—no risk of re-submitting the form if the user refreshes.

Common Confusion to Clear Up #

You might be wondering: "Do I have to use HttpResponseRedirect?" Technically no, but it’s a best practice you should follow to avoid user frustration and duplicate data.

Also, note that HttpResponseRedirect takes a URL path (or a reverse-resolved URL using reverse() in your view). For example:

from django.shortcuts import redirect, reverse

def output_view(request):
    if request.method == 'POST':
        form = YourForm(request.POST)
        if form.is_valid():
            # process your form data here
            return redirect(reverse('play_outcomes:results'))
    # handle invalid form or unexpected GET requests
    return redirect(reverse('play_outcomes:getinput'))

内容的提问来源于stack exchange，提问作者JohnB