Adding extra read-only information to a Django admin change page#

I figured out this pattern today for adding templated extra blocks of information to the Django admin change page for an object.

It’s really simply and incredibly useful. I can see myself using this a lot in the future.

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from django.contrib import admin
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from django.template.loader import render_to_string
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from django.utils.safestring import mark_safe
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from .models import Reporter
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@admin.register(Reporter)
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class ReporterAdmin(admin.ModelAdmin):
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    # ...
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    readonly_fields = ("recent_calls",)
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    def recent_calls(self, instance):
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        return mark_safe(
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            render_to_string(
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                "admin/_reporter_recent_calls.html",
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                {
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                    "reporter": instance,
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                    "recent_calls": instance.call_reports.order_by("-created_at")[:20],
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                    "call_count": instance.call_reports.count(),
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                },
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            )
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        )

That’s it! recent_calls is marked as a read-only field, then implemented as a method which returns HTML. That method passes the instance to a template using render_to_string. That template looks like this:

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<h2>{{ reporter }} has made {{ call_count }} call{{ call_count|pluralize }}</h2>
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<p><strong>Recent calls</strong> (<a href="/admin/core/callreport/?reported_by__exact={{ reporter.id }}">view all</a>)</p>
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{% for call in recent_calls %}
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    <p><a href="/admin/core/location/{{ call.location.id }}/change/">{{ call.location }}</a> on {{ call.created_at }}</p>
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{% endfor %}