Django templates and variable attributes


Question

I'm using Google App Engine and Django templates.
I have a table that I want to display the objects look something like:

Object Result:
    Items = [item1,item2]
    Users = [{name='username',item1=3,item2=4},..]

The Django template is:

<table>
<tr align="center">
    <th>user</th>
    {% for item in result.items %}
        <th>{{item}}</th>
    {% endfor %}
</tr>

{% for user in result.users %}
    <tr align="center"> 
        <td>{{user.name}}</td>
        {% for item in result.items %}
            <td>{{ user.item }}</td>
        {% endfor %}
    </tr>
{% endfor %}
</table>

Now the Django documention states that when it sees a . in variables
It tries several things to get the data, one of which is dictionary lookup which is exactly what I want but doesn't seem to happen...

1
34
7/17/2016 10:35:02 PM

Accepted Answer

I found a "nicer"/"better" solution for getting variables inside Its not the nicest way, but it works.

You install a custom filter into django which gets the key of your dict as a parameter

To make it work in google app-engine you need to add a file to your main directory, I called mine django_hack.py which contains this little piece of code

from google.appengine.ext import webapp

register = webapp.template.create_template_register()

def hash(h,key):
    if key in h:
        return h[key]
    else:
        return None

register.filter(hash)

Now that we have this file, all we need to do is tell the app-engine to use it... we do that by adding this little line to your main file

webapp.template.register_template_library('django_hack')

and in your template view add this template instead of the usual code

{{ user|hash:item }}

And its should work perfectly =)

32
9/8/2008 7:01:24 PM

I'm assuming that the part the doesn't work is {{ user.item }}.

Django will be trying a dictionary lookup, but using the string "item" and not the value of the item loop variable. Django did the same thing when it resolved {{ user.name }} to the name attribute of the user object, rather than looking for a variable called name.

I think you will need to do some preprocessing of the data in your view before you render it in your template.


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