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Template tag to create a list from one or more variables and/or literals

This code is taken from a [Stack Overflow answer by Will Hardy](http://stackoverflow.com/questions/3715550/creating-a-list-on-the-fly-in-a-django-template/3715794#3715794). Usage: `{% collect var1 var2 'foo' 'bar' 5 as some_list %}`. Sometimes one wishes to create a list on the fly within a template. Perhaps a collection needs to be passed to a template filter, but the collection cannot be created in the view since the values of one or more of its items are set in the template. A contrived example: {% with 5 as max %}{% with posts|length as len %} {% for post in posts %} {% if forloop.counter <= max %} {% include 'excerpt.dhtml' %} {% endif %} {% endfor %} {% collect len max as limits %} <p>Displaying {{ limits|minimum }} of {{ len }} post{{ posts|pluralize }}.</p> {% endwith %}{% endwith %} The final line will state how many posts are displayed: something like "5 of 24" or "2 of 2". This particular problem can be solved in a number of other ways, some of which are more appropriate. Having a template tag that can create lists on the fly is potentially useful in quite a few situations, though. I don't know whether this need is common enough to warrant being in the core. If something like this is to be included one day, it'd be much nicer to overload the `with` tag than to introduce a new tag. `{% with var1 var2 var3 as some_list %}` reads well.

  • template-tags
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Form with Two InlineFormSets

As I was unable to find good examples to render a Form with two or more inlineformsets. Therefor I have posted this to Django snippets. This code is little different from another snippet with a Form with one InlineFormSet (the prefixes are necessary in this situation). The example shows a person's data together with two inline formsets (phonenumbers and addresses) for a person. You can add, update and delete from this form.

  • form
  • inline
  • inlineformset
  • multiple-inlineformsets
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Search child models in django admin changelist

If you use django admin interface and have added an admin page for a model, django gives out-of-box search functionality in the model fields or foreignkey fields. One thing it doesn't support is searching in child models. For example you have created an admin page for Student model and there is model for courses which stores one or more courses taken by students and if you want to search by course name on the student page to see which students took a particular course. Django doesn't let you do that. I have written a small utility which will let you do that. Just copy the snippet in a file and then inherit from the ChildSearchAdmin instead of ModelAdmin and then you can specify which model/fields you want it to search on. The syntax is: **child_searches = [(ChildModel, 'field_to_search_on', 'foreign_key_field_in_child_model'),..] Example: class StudentAdmin(ChildSearchAdmin): child_searches = [(StudentCourse, 'course', 'student')]

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Debug middleware for displaying sql queries and template loading info when ?debug=true

Originally based on: [http://djangosnippets.org/snippets/1872/](http://djangosnippets.org/snippets/1872/) The way the original snippet formatted sql didn't work for mysql properly so I taught it to use the sqlparse python module. Now it looks like this when settings.DEBUG=True: SQL executed: SELECT "django_session"."session_key", "django_session"."session_data", "django_session"."expire_date" FROM "django_session" WHERE ("django_session"."session_key" = d326108d313a2e5c5fb417364b005ab9 AND "django_session"."expire_date" > 2011-04-08 14:54:13.969881) took 0.001 seconds SELECT "auth_user"."id", "auth_user"."username", "auth_user"."first_name", "auth_user"."last_name", "auth_user"."email", "auth_user"."password", "auth_user"."is_staff", "auth_user"."is_active", "auth_user"."is_superuser", "auth_user"."last_login", "auth_user"."date_joined" FROM "auth_user" WHERE "auth_user"."id" = 2 took 0.000 seconds Additionally, this middlware is enabled conditionally based upon the url query string "debug". You can enable it for a single request by appending: ?debug=true to the url.

  • middleware
  • development
  • debug
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Convert Q object to function

This is a function to take a Q object and construct a function which returns a boolean. This lets you use the exact same filter syntax that Django's managers use and apply it inside list comprehensions, or to non-persistent objects, or to objects of different types with the same attribute names.

  • q-objects
  • field
  • queryset
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Partial templates, combine with and include

This snippet adds simple partial support to your templates. You can pass data to the partial, and use it as you would in a regular template. It is different from Django's {% include %}, because it allows you to pass a custom variable (context), instead of reusing the same context for the included template. This decouples the templates from each other and allows for their greater reuse. The attached code needs to go into templatetags folder underneath your project. The usage is pretty simple - {% load ... %} the tag library, and use {% partial_template template-name data %} in your template. This will result in template passed as template-name to be loaded from your regular template folders. The variables are passed in a with compatiable syntax, eg. VAR as NAME and VAR as NAME No limitations on the number of variables passed.

  • template
  • templates
  • partial
  • with
  • include
  • partials
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Dynamic SITE_ID thread-safe

Store in SiteID a local var store for save SITE_ID thread-safe and set it with middleware. It's base on https://djangosnippets.org/snippets/1099/ but with call to local() in SiteID and using custom models for web site and domains.

  • dynamic
  • site_id
  • thread-locals
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Author: jhg
  • 1
  • 0

CallTag - Just like include, but can pass parameters to it

I knew that template in myght template system can receive some parameters just like a function. And I also want to implement this function in django template. So I finish a rough one, the code is pasted here. It just like include, but in order to distinguish with "include" tag, I call it "call". So you can use it: {% call "some.html" %} This way just like include tag, and the advanced way: {% call "some.html" with "a" "b"|capfirst title="title1" %} {% call "some.html" with "c" "d" title="title2" %} So you can see, "call" tag can do like a python function, it can receive tuple parameters and key word parameters, just like the function: def func(*args, **kwargs):pass How to use it =============== test_call.html {% expr "limodou" as name %} {% call "test/test_sub.html" with "a"|capfirst "b" title="title1" %}<br/> {% call "test/test_sub.html" with "c" "d" title="title2" %} expr is also a custom tag written by me. It'll calculate a python expression and save to result to a variable. In this case, the variable it "name". test_sub.html {% for i in args %}{{ i }}{% endfor %} <h2>{{ title }}</h2> <p>{{ name }}</p> <h3>args</h3> {{ args }} <h3>kwargs</h3> {{ kwargs }} And you also can see, call tag will auto create args and kwargs context variables. I hope this will be some useful.

  • tag
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ExprTag - Calculating python expression and saving the result to a variable

This tag can be used to calculate a python expression, and save it into a template variable which you can reuse later or directly output to template. So if the default django tag can not be suit for your need, you can use it. How to use it {% expr "1" as var1 %} {% expr [0, 1, 2] as var2 %} {% expr _('Menu') as var3 %} {% expr var1 + "abc" as var4 %} ... {{ var1 }} for 0.2 version {% expr 3 %} {% expr "".join(["a", "b", "c"]) %} Will directly output the result to template Syntax {% expr python_expression as variable_name %} python_expression can be valid python expression, and you can even use _() to translate a string. Expr tag also can used context variables.

  • tag
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Url filter middleware

How to config it ------------------ You can treat it as a micro url filter framework. Before you using it, you should setup some options about it. The option entry shoud be like this: FILTERS = ( (r'^user/(?P<user_id>\d+)/', 'apps.users.filter.check_valid_user'), ) FILTERS should be a list or tuple with two elements tuple item. The format should be like: (url_patterns, function) And url_patterns could be a single regex expression or a list/tuple regex expressions, So you can set multi regex expression in it. And the regulation is just like url dispatch, as above example, the url pattern is: r'^user/(?P<user_id>\d+)/' So you can see, you can set parameter name `user_id`, then it'll be passed to the function behind. Function can be a string format, just like above example, and it can be also a real function object. It'll only impact request. How to write filter function ------------------------------- According above example, I define a url pattern, and what to check if the user is a valid user, and if the user is visiting his own urls, so the filter function could be: from django.contrib.auth.models import User from utils.common import render_template def check_valid_user(request, user_id): if request.user.is_anonymous(): return render_template(request, 'users/user_login.html', {'next':'%s' % request.path}) try: person = User.objects.get(pk=int(user_id)) except User.DoesNotExist: return render_template(request, 'error.html', {'message':_("User ID (%s) is not existed!") % user_id}) if person.id != request.user.id: return render_template(request, 'error.html', {'message':_('You have no right to view the page!')}) I think the code is very clear. And you can use it filtermiddleware to do like user authentication check, and other checking for url. BTW, render_template is comes from [Snippets #4](http://www.djangosnippets.org/snippets/4/)

  • middleware
  • filter
  • url
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DRY with common model fields

If you have many models that all share the same fields, this might be an option. Please note that order matters: Your model need to inherit from TimestampedModelBase first, and models.Model second. The fields are added directly to each model, e.g. while they will be duplicated on the database level, you only have to define them once in your python code. Not sure if there is a way to automate the call to TimestampedModelInit(). Tested with trunk rev. 5699. There is probably a slight chance that future revisions might break this.

  • models
  • model
  • inheritance
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Decorating urlpatterns

One thing I wanted for a while was the ability to basically apply something like @login_required to a bunch of urlpatterns in one go, instead of having to decorate each and every view manually. In this example, the latter two views will always raise a 404.

  • urls
  • views
  • decorators
  • urlpatterns
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newforms self-contained login form

A simple login form that does the actual authentification itself. **Usage:** if request.method == "POST": loginform = LoginForm(request.POST) if loginform.login(): return HttpResponseRedirect(redir_url) else: loginform = LoginForm()

  • newforms
  • login
  • auth
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