Django-从模板传递参数到视图不起作用

Question

I'm trying to get my hands dirty with django and I started trying to make my own project. I'm currently having trouble passing parameters from my template to my views without using POST requests.

heres my code in the template

#in main.html

<div>
    {{ event_results }}
    {{ friends }}
</div>

{% for user in results %}
    <div class="userblock">
        <p class="user">{{ user.username }}</p>
            <a href="/events/addFriend/{{user.username}}">
                <button class="navbuttons" id="addfriend">Add as friend</button>
            <a/>
    </div>
{% endfor %}

#in urls.py

from django.conf.urls import patterns, url
from events import views, eventview

url(r'^addFriend/(<requested_friend>[a-z]*)/', views.addFriend, name='addFriend'),
)

#in views.py

def addFriend(request, requested_friend):
    currentUser = User.objects.get(username=request.session['username'])
    try:
        list_of_friends = Friends.objects.get(username=currentUser)
    except (KeyError, Friends.DoesNotExist):
        return render(request, 'events/main.html', {'friends': requested_friend})
    else:
        return render(request, 'events/main.html', {'friends':list_of_friends})

So when I click on the button "Add friend" in main.html, it goes to the url.py and maps it to the function addFriend in views.py with the argument and from there it does its magic. However, it's not taking in the argument. I know I'm doing something wrong in the urls.py with the regex but im not sure what. Any advice is greatly appreciated. Thanks!

Answer 1

When you change (<requested_friend>[az]*) to (?P<requested_friend>[0-9A-Za-z_\\-]+) than everything looks fine.

But remember to use + instead of * in the pattern. * matches also a empty string ( addFriend// is matched) but with + the string must have at least one character ( addFriend// isn't matched)

You can add $ on the end of url pattern r'^addFriend/(?P<requested_friend>[0-9A-Za-z_\\-]+)/$' Here you can find why.

Also check if link in browser has correct value /events/addFriend/<user_name>/ maybe is something wrong with {{ user.username }}

Answer 2

You have error in urls.py. In named group pattern you miss ?P prefix. See doc for reference .

Instead of

url(r'^addFriend/(<requested_friend>[a-z]*)/', views.addFriend, name='addFriend'),

It should be:

url(r'^addFriend/(?P<requested_friend>[a-z]*)/', views.addFriend, name='addFriend'),