I am new to Django and I am trying to find out how can I associate a HTML snippet with a model.
My HTML snippet is just a div. I want to reuse that div (you can think of it like a thumbnail)
Situation is like this: In my main page I want to show x objects and in my search page I want to show more objects. But the representation is the same.
I can write in the mainpage.html and searchpage.html the desired way of transforming the model object into a div but I am not sure what is the best way to reuse that transform?
I can add a function to my model which returns a HTML div, then I can call it from mainpage and searchpage templates. But that will couple the model and representation, which I believe is not a very nice thing to do.
If I am not mistaken inclusion_tags are the way to go but in which file should I keep the function definition?
As you rightly say, you don't want html in your models, it's goes against the MVC pattern.
Models are for storing data. Views are for selecting the data to present whilst Templates are used for the actual presentation of data. (See this note on django's interpretation of MVC).
To answer your question, you need a template (or even a template tag), to represent your model, say model_block.html. Something like
{% if obj %}
<div id=obj.id>
{{ obj.name }}
</div>
{% endif %}
Then include your template in your mainpage.html like
{% for obj in object_list %}
{% include 'model_block.html' %}
{% endfor %}
You can do the same thing in your searchpage.html, passing a different object_list variable from your view.
Related
I have a template that receives a list context variable, tags_list. I need to iterate over this list 'inserting' the tags in the template something like this:
{% for tag in tags_list %}
{{ tag.tag }}
{% endfor %}
When this renders it returns the text value of tag.tag, "{% tagxxx %}", not the rendered tag.
How can I cause the template render to render the value of a context variable? Alternately, is there a filter, a sort of inverse verbatim, that will cause the value of a context variable to be rendered?
Updated background
tags_list is created by a fairly sophisticated process involving exec of some user provided text from a table/model field. The relevant portion of the real template looks like this:
{% for graph_row in graph_rows %}
<div class="row">
{% for graph in graph_row %}
<div class="col-md-{{ graph.width }}">
{{ graph.graph }}
</div>
{% endfor %}
</div>
{% endfor %}
The graph values look like this: {'graph':'{% piechart data1 %}', 'width':3}
Note that the order of entries in the context variable graph_rows is significant as is order of graph(s) in the row as that determines the placement of graphs on the page. Preserving this order is essential for the scheme to work correctly.
Currently, the view function simply does an {% include ... %} to get the template segment above to render in the correct order. This approach is simple and clean.
I could, as has been suggested, perform a template render within the view function but that complicates the design a bit and I'd hoped to avoid doing that if there is an easy way to trigger a render of {{ graph.graph }}. Note, as well, by moving the render into the view I loose the ability to easily take the template from arbitrary places, in particular table fields.
One of the great things about Django is the library of solution and code snippets. Sadly, they aren't a well organized and easy to find as one might wish. Nevertheless, a bit of google found a number of solutions of the general form
{% render tag.tag %}
Here are links to several:
render_as_template template tag
Allow template tags in a Flatpage's content
render_as_template.py
I'll use the general approach cleaned up a bit for error checking.
As an aside, the technique strikes me as generally useful and might be appropriate for inclusion in the standard tags.
Update 3/28/2014
After looking at the above and several others this is what I used from render_as_template template tag. There is a useful comment here.
from django import template
from django.template import Template, Variable, TemplateSyntaxError
register = template.Library()
class RenderAsTemplateNode(template.Node):
def __init__(self, item_to_be_rendered):
self.item_to_be_rendered = Variable(item_to_be_rendered)
def render(self, context):
try:
actual_item = self.item_to_be_rendered.resolve(context)
return Template(actual_item).render(context)
except template.VariableDoesNotExist:
return ''
def render_as_template(parser, token):
bits = token.split_contents()
if len(bits) !=2:
raise TemplateSyntaxError("'%s' takes only one argument"
" (a variable representing a template to render)" % bits[0])
return RenderAsTemplateNode(bits[1])
render_as_template = register.tag(render_as_template)
This gets part of the way to a solution. Unfortunately custom template tags, in my case
{% pie_chart %} are not available to render within the class RenderAsTemplateNode.
I've not tested this but it appears that this stack overflow question, Django - replacing built-in templatetag by custom tag for a whole site without {% load .. %}, points the way.
I believe I can provide a way for you to get the results you want, but there might be a better way for you to achieve the desired functionality if you can provide some context.
Anyway, you might do something like this in your view.py:
tags_list = [
Template('{% load my_tags %}{% ' + t.tag + ' %}').render(Context())
for t in tags_list
]
I have a template that looks something like:
Main Template, home.html:
{% extends "framed.html" %}
<h2> stuff <h2>
framed.html looks something like
{% block header %}
<h1>{{ sitename }}</h1>
{% endblock %}
Normally when I call these views I give it a context with a context containing a key "sitename" assigned get_current_site().name, which works fine.
I also, however, would like to use framed.html at the top of a bunch of templates that are also called by django default views. For example:
return HttpResponseRedirect(reverse('django.contrib.auth.views.login'))
The top of that page never gets the {{sitename}} to show up, so I end up with some blank space at the top of my page. The same goes for flat pages, logouts, etc. Is there a way I can get the relevant context added to all of these "built-in" pages?
You can write your own template context processor that will add required variable in the parameters provided to each template.
More details at Writing your own context processors
I'm making a forum with django right now, and I want it so that anyone can comment on anyone else's comment. Right now I have a foreign key in my 'Comment' model that points back to itself so I can get the parent comment easily from any comment.
In my theory this worked great, because from any comment I could get all of its child comments, and then just keep branching down from there to get every single child comment. However I'm having trouble actually implementing this when it comes to getting the data from the view to the template.
I want it to be possible to have an infinite number of child comments, because who knows how long a discussion will last and I don't want to arbitrarily limit it. The problem I'm having is would you get all of those comments from the view to the template without losing their relationship to their parent comment?
Currently this is what the psuedocode for my code looks like:
#the view
def comment_page(request, forum, comment_id):
#this is the main comment that all others will stem from
main_comment = Comment.objects.get(id=comment_id)
children_comments = main_comment.comment_set.all()
#the template
{% for comment in children_comments %}
<p class='comment'>{{comment}}</p>
{% endfor %}
Obviously I'm not even trying to get all the child comments here, it just gets child comments of the very first post. What I don't understand is how can I then go through each of these child comments and then get all of theirs, and keep doing that for each new comment?
It makes the most sense to do it in the view since I am able to use Django's QuerySet API in there, but I don't see how I would be able to pass all of the comments to the template without losing their relationship to their parent. The only idea I can think of is to go through all of the comments in the view and build up a string of html that I just pass and simply display in the template, but that seems like a horrible idea because it'd be dealing with template related stuff in the view.
You might want to look into using a MPTT such as django-mptt
this can be implemented by a custom filter with an inclusion_tag that includes itself but causes a lots of queries to your db:
#register.inclusion_tag('children.html')
def comments_tree(comment):
children = comment.comment_set.all()
return {'children': children}
# children.html
<ul>
{% for child in children %}
<li> {{ child }}</li>
{% if child.comment_set.count > 0 %}
{% comments_tree child %}
{% endif %}
{% endfor %}
</ul>
# your template
{% comments_tree comment %}
This older question is probably of interest:
How can I render a tree structure (recursive) using a django template?
Edit: to future readers, don't do this as the inner for loop's comment variable does not substitute the outer comment variable during the loop execution, leading to infinite recursion. /Edit
If you need a recursive tree structure in your HTML page (i.e. a bunch of nested <div> tags), you can write a recursive "comment" template.
Sample: (untested)
{# comment.html #}
<p class='comment'>{{ comment.text }}</p>
{% if comment.children %}
{% for comment in comment.children %}
{% include "comment.html" %}
{% endfor %}
{% endfor %}
The for loop binds the comment template variable to each child before including itself.
Performance note: Unless your comment sets are often short, this will probably be very slow. I recommend that you make your comments non-editable and cache the result!
Alternate solution: If you don't need the recursive HTML <div> tags, you can write a generator that performs a pre-order traversal of the structure and yields (depth, comment) pairs. This would likely be far more efficient in rendering speed.
I have a django template which loops over many notes/comments. As a simplified example take this.
{% for note in notes %}
<p>
Date added: {{ note.date_added }}
{{ note.note|urlize|url_target_blank|linebreaks }}
</p>
{% endfor %}
Then on the same page I have a form to add a new note. This note form is an ajax form and returns the newly submitted note back to the page and appends it at the end of the already existent note area.
I don't like this because I have to maintain the same html structure both in the page for the initial load, as well as in the response from the ajax form.
Is there a way to put a call to another template, inside of a template (in this for loop) so I can maintain the note formatting in one location only?
Thanks.
Perhaps you're looking for the "include" tag: http://docs.djangoproject.com/en/dev/ref/templates/builtins/#include
I have template that displays object elements with hyperlinks to other parts of my site. I have another function that displays past versions of the same object. In this display, I don't want the hyperlinks.
I'm under the assumption that I can't dynamically switch off the hyperlinks, so I've included both versions in the same template. I use an if statement to either display the hyperlinked version or the plain text version. I prefer to keep them in the same template because if I need to change the format of one, it will be easy to apply it to the other right there.
The template extends framework.html. Framework has a breadcrumb system and it extends base.html. Base has a simple top menu system.
So here's my dilemma. When viewing the standard hyperlink data, I want to see the top menu and the breadcrumbs. But when viewing the past version plain text data, I only want the data, no menu, no breadcrumbs. I'm unsure if this is possible given my current design. I tried having framework inherit the primary template so that I could choose to call either framework (and display the breadcrumbs), or the template itself, thus skipping the breadcrumbs, but I want framework.html available for other templates as well. If framework.html extends a specific template, I lose the ability to display it in other templates.
I tried writing an if statement that would display a the top_menu block and the nav_menu block from base.html and framework.html respectively. This would overwrite their blocks and allow me to turn off those elements conditional on the if. Unfortunately, it doesn't appear to be conditional; if the block elements are in the template at all, surrounded by an if or not, I lose the menus.
I thought about using {% include %} to pick up the breadcrumbs and a split out top menu. In that case though, I'll have to include it all the time. No more inheritance. Is this the best option given my requirement?
You can put your hyperlinks inside a block that is overridden by the loading templates.
Let's say you have your framework.html like this:
{% extends "base.html" %}
<html>...<body>...
{% block hyperlinks %}
your hyperlinks here
{% endblock %}
rest of the code
</body></html>
You can then create something of a nolinks.html template and use it
{% extends "framework.html" %}
{# here you'll have everything from framework
but now we disable the breadcrumbs #}
{% block hyperlinks %}{% endblock %}
If you're getting the past data you can then use nolinks to render instead of framework.
I hope this helps.
From here: Any way to make {% extends '...' %} conditional? - Django
It can be done like this :
{% extends ajax|yesno:"ajax_base.html,main_base.html" %}
Or:
{% extends a_variable_containing_base_template_name %}
Which ever best suited for you.
Regards;