List of changed fields

[eriktelepovsky]

Hi. Thank you very much for your library. It is very useful. I am wondering if it is possible to get a list of fields and their values that changed between each history version.

Something like this:
http://django-dirtyfields.readthedocs.io/en/develop/#verbose-mode

[feeh27]

Hello @eriktelepovsky

You can retrieve the data by using a ListView.

Assuming your django-simple-history is correctly configured, follow the procedures below:

Model models.py

from django.db import models
from simple_history.models import HistoricalRecords

# Create your models here.

class Poll(models.Model):
    question = models.CharField(max_length=200)
    history = HistoricalRecords()

View views.py

from django.shortcuts import render
from django.views.generic import ListView
from .models import Poll

# Create your views here.

class PollHistoryView(ListView):
    template_name = "pool_history_list.html"
    def get_queryset(self):
        history = Poll.history.all()
	    return history

Template pool_history_list.html

<table>
	<thead>
		<tr>
			<th>Question</th>
			<th>History Date/Time</th>
			<th>History Action</th>
			<th>History User</th>
		</tr>
	</thead>
	<tbody>
		{% for t in object_list %}
		<tr>
			<td>{{ t.id }}</td>
			<td>{{ t.question }}</td>
			<td>{{ t.history_date }}</td>
			<td>{{ t.get_history_type_display }}</td>
			<td>{{ t.history_user }}</td>
		</tr>
		{% endfor %}
	</tbody>
</table>

As above the history of all models will appear.

To filter the object you want the history just modify the excerpt:

history = Poll.history.all()

For the excerpt below:

id_filter = id_to_be_filtered
filteredPoll = Poll.objects.filter(id=id_filter)
history = filteredPoll.history.all()

[madan0309]

Hello @feeh27
Recently I have installed Django-simple-history, the idea of reverting back the model instance is great. but as @eriktelepovsky stated I am not able to find the changes between history versions.

The solution above works if I have few attributes to the model but I have around 20 attributes to my model where it is hard to find the changes between versions.

I expect at least the comment should be informative like displaying what fields got changed (As we have by default Django LogEntry).

[marcosox]

I second the need for having somewhere a way to detect which fields changed at each snapshot.
Currently, trying to audit the history of a model with many fields is difficult, because one has to manually compare the snapshots to see where the changes occurred.

[eriktelepovsky]

Something like this functionality in a similar app would be useful:

https://github.com/jjkester/django-auditlog/blob/master/src/auditlog/models.py#L242

Usage in the template:

{% if object.history.all.count %}
    <table>
        <thead>
            <tr>
                <th>{% trans 'Timestamp' %}</th>
                <th>{% trans 'Actor' %}</th>
                <th>{% trans 'Action' %}</th>
                <th>{% trans 'Changes' %}</th>
            </tr>
        </thead>
        <tbody>
            {% for history in object.history.all %}
                <tr>
                    <td>
                        {{ history.timestamp }}
                    </td>
                    <td>
                        {{ history.actor|default:_('System') }}
                    </td>
                    <td>
                        {{ history.get_action_display }}
                    </td>
                    <td>
                        {% if history.action == history.Action.UPDATE %}
                            <table>
                            {% for field, values in history.changes_display_dict.items %}
                                <tr>
                                    <td><strong>{{ field }}</strong></td>
                                    <td>{% if values.0 != 'None' %}<strike>{{ values.0|default:'' }}</strike>{% endif %}</td>
                                    <td>{% if values.1 != 'None' %}{{ values.1 }}{% endif %}</td>
                                </tr>
                            {% endfor %}
                            </table>
                        {% endif %}
                    </td>
                </tr>
            {% endfor %}
        </tbody>
    </table>
{% endif %}

[rossmechanic]

#416 should solve this

[peuhrdf]

#416 should solve this

Function to get all changes by id:

def historical_changes(qry, id):
    changes = []
    if qry is not None and id:
        last = qry.first()
        for all_changes in range(qry.count()):
            new_record, old_record = last, last.prev_record
            if old_record is not None:
                delta = new_record.diff_against(old_record)
                changes.append(delta)
            last = old_record
    return changes

In template:

<table class="table">
	<thead>
		<tr>
			<th>id</th>
			<th>date/time</th>
			<th>change made</th>
			<th>responsible</th>
		</tr>
	</thead>
	<tbody>
		{% for change in changes %}
            <tr>
                <td>{{ change.new_record.id }}</td>
                <td>{{ change.new_record.history_date }}</td>
                <td>
                    {% if change.changed_fields|length > 0 %}
                        {% for change_by_id in change.changes %}
                            The field:<b>{{ change_by_id.field|title }}</b>was changed from:
                            {% if change_by_id.old %}
                               <b>{{ change_by_id.old }}</b>
                                {% else %}
                                <b>blank field</b>
                            {% endif %}
                            for <b>{{ change_by_id.new }}</b>
                            <br>
                        {% endfor %}
                    {% else %}
                        There were no changes in this edition
                    {% endif %}
                </td>
                <td>{{ change.new_record.history_user }} - {{ change.new_record.history_user.first_name }} </td>
              </tr>
		{% endfor %}
	</tbody>
</table>

[aceaceace30]

is it possible to display the str instead of id for the foreign key fields

[alnikolaj]

pretty much what aceaceace30, how can we get the name of the foreign key instead of the id?

[foggy54]

if anyone found the way to display the values instead ID for foreign_keys ?

[9akashnp8]

Hey guys, pretty old thread but you can use custom template tags to get the name or any field instead of id

1. Create a tag (Reference) :

My example:

def emp_id_to_name(emp_id):
    emp_name = Employee.objects.get(emp_id=emp_id).emp_name
    return emp_name

2. Use the filter in template

{{change_by_id.old|emp_id_to_name}}

[Odissine]

It's old too but this kind of approach works only for a specifc ForeignKey filter ... is there any built in function to display data from id depending on the name of model and field ? I try with is_relation but works only in foreign key model as in history model it's id recorded not foreignkey ...
Thanks so much for this method so to show all modification made ... miss only one thing for my need ... getting string from foreignkey ... I'm working on in await ;)THanks