Button Admin

CHANGE TEMPLATES===============================================================
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In a folder referenced in settings.TEMPLATE_DIRS create two files :
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*******************************************************************************
    /admin/<app>/change_form.html
*******************************************************************************

{%extends "admin/change_form.html" %}

{% load i18n admin_modify adminmedia %}

<!-- Object-Tools -->
{% block object-tools %}
{% if change %}
{% if not is_popup %}
<ul class="object-tools">
    {% for button in buttons %}{% if not button.forAll %}{% if button.show %}
        {% if not button.saveOnClick %}<li>{{button}}</li>{% endif %}
    {% endif %}{% endif %}{% endfor %}
    
    <li><a href="history/">{% trans "History" %}</a></li>
    {% if has_absolute_url %}
        <li><a href="../../../r/{{ content_type_id }}/{{ object_id }}/" class="focus" target="_blank">{% trans "View on site" %}</a></li>   
    {% endif%}
</ul>
{% endif %}
{% endif %}
{% endblock %}

{% block after_related_objects %}
    <div class="submit-row">
    {% for button in buttons %}{% if not button.forAll %}{% if button.show %}
    
        {% if button.saveOnClick %}
            {{button}}
        {% endif %}{% endif %}
    
    {% endif %}{% endfor %}
    </div>
{% endblock %}

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    /admin/<app>/change_list.html
*******************************************************************************

{%extends "admin/change_list.html" %}
{% load i18n %}

{% block object-tools %}
  {% if has_add_permission %}
    <ul class="object-tools">
        {% for button in buttons %}{% if button.show %}
            {% if button.forAll %}<li>{{button}}</li>{% endif %}
        {% endif %}{% endfor %}
      <li>
        <a href="add/{% if is_popup %}?_popup=1{% endif %}" class="addlink">
          {% blocktrans with cl.opts.verbose_name as name %}Add {{ name }}{% endblocktrans %}
        </a>
      </li>
    </ul>
  {% endif %}
{% endblock %}
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BUTTON ADMIN CLASSES===========================================================
------------------------********************-----------------------------------
Create a file somewhere that you can import into your admin.py 
and put the following in it
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from django.template import loader, RequestContext, Context, Template
from django.http import HttpResponse, HttpResponseRedirect
from django.utils.translation import ugettext as _
from django.utils.functional import update_wrapper
from django.utils.encoding import force_unicode
from django.shortcuts import get_object_or_404
from django.utils.safestring import mark_safe
from django.contrib.admin.util import unquote
from django.contrib.admin import helpers
from django.utils.text import capfirst
from django.utils.html import escape
from django.contrib import admin
from django.http import QueryDict

class Button(object):
    def __init__(self, url, desc, kls=None, saveOnClick=True, forAll=False, display=True, needSuperUser=True):
        if forAll:
            saveOnClick = False
        self.url = url
        self.desc = desc
        self.kls = kls
        self.display = display
        self.saveOnClick = saveOnClick
        self.forAll = forAll
        self.needSuperUser = needSuperUser
            
    def __unicode__(self):
            
        if not self.saveOnClick or self.forAll:
            if self.saveOnClick or not self.url.startswith('/'):
                url = "tool_%s" % self.url
            else:
                url = self.url
        
            link = u'<a href="%s"' % url
            if self.kls:
                link += u' class="%s"' % self.kls
            link += u'>%s</a>' % self.desc
        else:
            link = u'<input type="submit" name="tool_%s" value="%s"/>' % (self.url, self.desc)
        return mark_safe(link)

    def determineIfShow(self, user):
        if (self.needSuperUser and not user.is_superuser) or not self.display:
            self.show = False
        else:
            self.show = True
    
class ButtonAdminMixin(object):
    def tool_urls(self):
        """Mostly copied from django.contrib.admin.ModelAdmin.get_urls"""
        
        from django.conf.urls.defaults import patterns, url

        def wrap(view):
            def wrapper(*args, **kwargs):
                return self.admin_site.admin_view(view)(*args, **kwargs)
            return update_wrapper(wrapper, view)

        info = self.model._meta.app_label, self.model._meta.module_name
        
        urls = []
        for button in self.buttons:
            urls.append(
                url(r'^(.+)/tool_%s/$' % button.url,
                    wrap(self.button_url),
                    kwargs = dict(button=button),
                    name = '%s_%s_tool_%%s' % info % button.url,
                )
            )
            
        urlpatterns = patterns('', *urls)
        return urlpatterns

    
    def button_url(self, request, object_id, button):
    
        model = self.model
        obj = get_object_or_404(model, pk=object_id)
        result = getattr(self, "tool_%s" % button.url)(request, obj, button)
        
        try:
            File, extra = result
        except:
            return result
        
        opts = model._meta
        app_label = opts.app_label
        context = {
            'title': _('%s: %s') % (button.desc, force_unicode(obj)),
            'module_name': capfirst(force_unicode(opts.verbose_name_plural)),
            'object': obj,
            'root_path': self.admin_site.root_path,
            'app_label': app_label,
            'bread_title' : button.desc,
        }
        context.update(extra or {})
        
        t = loader.get_template(File)
        c = RequestContext(request, context)
        return HttpResponse(t.render(c))

class ButtonAdmin(admin.ModelAdmin, ButtonAdminMixin):
    """Unfortunately I can't add these to the mixin, but I still want to have the mixin stuff as a mixin"""
    def changelist_view(self, request, extra_context=None):
        if not extra_context:
            extra_context = {}
        
        [b.determineIfShow(request.user) for b in self.buttons]
        extra_context['buttons']=self.buttons
        
        return super(ButtonAdmin, self).changelist_view(request, extra_context)
        
    def change_view(self, request, object_id, extra_context=None):
        if not extra_context:
            extra_context = {}
        
        [b.determineIfShow(request.user) for b in self.buttons]
        extra_context['buttons']=self.buttons
        
        result = super(ButtonAdmin, self).change_view(request, object_id, extra_context)
        
        redirect = None
        for key in request.POST.keys():
            if key.startswith("tool_"):
                redirect = key
                
        if not redirect:
            return result
        else:
            #a lot of this is copied from django.contrib.admin.ModelAdmin.change_view
            model = self.model
            opts = model._meta

            try:
                obj = self.queryset(request).get(pk=unquote(object_id))
            except model.DoesNotExist:
                # Don't raise Http404 just yet, because we haven't checked
                # permissions yet. We don't want an unauthenticated user to be able
                # to determine whether a given object exists.
                obj = None

            if not self.has_change_permission(request, obj):
                raise PermissionDenied

            if obj is None:
                raise Http404(_('%(name)s object with primary key %(key)r does not exist.') % {'name': force_unicode(opts.verbose_name), 'key': escape(object_id)})

            if request.method == 'POST' and request.POST.has_key("_saveasnew"):
                return self.add_view(request, form_url='../add/')

            ModelForm = self.get_form(request, obj)
            formsets = []
            if request.method == 'POST':
                form = ModelForm(request.POST, request.FILES, instance=obj)
                if form.is_valid():
                    form_validated = True
                    new_object = self.save_form(request, form, change=True)
                else:
                    form_validated = False
                    new_object = obj
                prefixes = {}
                for FormSet in self.get_formsets(request, new_object):
                    prefix = FormSet.get_default_prefix()
                    prefixes[prefix] = prefixes.get(prefix, 0) + 1
                    if prefixes[prefix] != 1:
                        prefix = "%s-%s" % (prefix, prefixes[prefix])
                    
                    try:
                        formset = FormSet(request.POST, request.FILES,
                                      instance=None, prefix=prefix)
                        formsets.append(formset)
                    except:
                        #Deleted items can cause this to fail.
                        pass
                    
                errors = helpers.AdminErrorList(form, formsets)
                if not errors:
                    return HttpResponseRedirect(redirect)
                            
        return result
        
    def urls(self):
        if hasattr(self, 'buttons'):
            return self.tool_urls() + self.get_urls()
        else:
            return self.get_urls()
    urls = property(urls)
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USAGE==========================================================================
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In your desired admin model there's three parts to enabling this
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1) Make sure your admin model inherits from ButtonAdmin
2) Add a Buttons attribute to your admin
3) Add necessary functions that are called

<import ButtonAdmin, Button>

class Test(ButtonAdmin):
    buttons = (
        Button('test', "A Test Button"),
        Button('redirect', "A redirect"),
    )
    
    def tool_test(self, request, obj, button):
        return 'templates/test.html', {"message" : "a test"}
    
    def tool_redirect(self, request, obj, button):
        return HttpResponseRedirect('/somewhere')
        
Each button has the following parameters : url, desc, kls=None, saveOnClick=True, forAll=False, display=True, needSuperUser=True

* forAll : determines whether the button shows up on the change form or the change list. 
    If forAll is False, it appears on the change form. 
    The function that is called is called tool_<url> and receives :
           the request object, the object being edited and the button object.

    If forAll is True, it appears on the change list. 
    Unfortunately you must create your url and view somewhere else 
    and pass in the aboslute url to this view as the url parameter to the button (limitation of django admin)

* desc : what is displayed on the button

* kls : specifies the css class of the button

* saveOnClick : Determines if the form is saved when the button is clicked or not. 
    If set to True : the form is saved before the function is called 
                     and the button appears at the bottom
    If set to False : the form is not saved before the function is called 
                      and the button appears at the top
    This doesn't apply when forAll is set to True
   
* display : determines if the button should be displayed or not 
(doesn't effect url creation)

* needSuperUser : if set to true then only super users can see the button


The functions can return either a HttpResponse object or a two value tuple of template name, and extra context. 
When the tuple is returned it will render the template with the given context.