custom html field in the django admin changelist_view

Question

I'd like to some little customisation with the django admin -- particularly the changelist_view

class FeatureAdmin(admin.ModelAdmin):
    list_display = (
        'content_object_change_url',
        'content_object',
        'content_type',
        'active',
        'ordering',
        'is_published',
    )

    list_editable = (
       'active',
       'ordering',
    )

    list_display_links = (
        'content_object_change_url',
    )

admin.site.register(get_model('features', 'feature'), FeatureAdmin)

The idea is that the 'content_object_change_url' could be a link to another object's change_view... a convenience for the admin user to quickly navigate directly to the item.

The other case I'd have for this kind of thing is adding links to external sources, or thumbnails of image fields.

I had thought I'd heard of a 'insert html' option -- but maybe I'm getting ahead of myself.

Thank you for your help!

Answer 1

You can provide a custom method on the FeatureAdmin class which returns HTML for content_object_change_url:

class FeatureAdmin(admin.ModelAdmin):

    [...]

    def content_object_change_url(self, obj):
        return '<a href="%s">Click to change</a>' % obj.get_absolute_url()
    content_object_change_url.allow_tags=True

See the documentation.

Answer 2

Pay attention and use format_html (See docs here) as the mark_safe util has been deprecated since version 1.10. Moreover, support for the allow_tags attribute on ModelAdmin methods will be removed since version 1.11.

from django.utils.html import format_html
from django.contrib import admin

class FeatureAdmin(admin.ModelAdmin):
    list_display = (
        'change_url',
        [...]
    )
    def change_url(self, obj):
        return format_html('<a target="_blank" href="{}">Change</a>', obj.get_absolute_url())
    change_url.short_description='URL'

Answer 3

It took me two hours to find out why Daniel Roseman's solution doesn't work for me. Even though he is right, there's one exception: when you want to make custom calculated fields (read only) in the Admin. This wont work. The very easy solution (but hard to find) is to return your string in a special constructor: SafeText(). Maybe this is linked with Django 2 or with readonly_fields (which behave differently from classical fields)

Here's a working sample that works but doesn't without SafeText():

from django.utils.safestring import SafeText

class ModelAdminWithData(admin.ModelAdmin):

    def decrypt_bin_as_json(self, obj):
        if not obj:
            return _("Mode insert, nothing to display")
        if not obj.data:
            return _("No data in the game yet")
        total = '<br/><pre>{}</pre>'.format(
            json.dumps(json.loads(obj.data),
                       indent=4).replace(' ', '&nbsp;'))
        return SafeText(total)  # !! working solution !! <------------------

    decrypt_bin_as_json.short_description = _("Data")
    decrypt_bin_as_json.allow_tags = True

    readonly_fields = ('decrypt_bin_as_json',)

    fieldsets = (
        (_('Data dump'), {
            'classes': ('collapse',),
            'fields': ('decrypt_bin_as_json',)
        }),
    )