I'm facing an issue which is somewhat reverse of Django reversion does not save revisions made in shell
Versions being used:
Django: v1.3.1
django-reversion: v1.5.7
I wrote a class that can be used to save/discard changes made to a model:
import reversion, datetime
class Execute:
model = None
delete_ids = []
def __init__(self, model):
self.model = model
if not reversion.is_registered(model):
reversion.register(model)
def update(self, n):
id = n.pk
if len(self.model.objects.filter(pk=id)) > 0:
m= self.model.objects.get(pk=id)
if len(reversion.get_for_object(m)) == 1: # Update newly inserted element
reversion.get_for_object(m).delete() # reversion list only 1 long.
with reversion.create_revision():
m=n
m.save()
else: # Update existing element. reversion list will be at least 2 long
if len(reversion.get_for_object(m)) == 0: # Add self as first revision.
with reversion.create_revision():
m.save()
with reversion.create_revision(): # Add updates
m=n
m.save()
def insert(self, n):
with reversion.create_revision():
n.pk = None
n.save()
return n.pk
def delete(self, n):
id = n.pk
if len(self.model.objects.filter(pk=id)) > 0:
m=self.model.objects.get(pk=id)
with reversion.create_revision():
m.save()
delete_ids.append(id)
m.delete()
def discard(self, n):
id = n.pk
if len(self.model.objects.filter(pk=id)) > 0:
m=self.model.objects.get(pk=id)
rev=reversion.get_for_object(m)
if len(rev) == 0:
return
if len(rev) == 1: #insert operation, then delete
m.delete()
else: #update operation, then revert
rev[len(rev)-1].revert()
rev.delete()
if len(reversion.get_deleted(self.model).filter(object_id=id)) > 0:
reversion.get_deleted(self.model).get(object_id=id).revert()
def save(self, n):
id = n.pk
if len(self.model.objects.filter(pk=id)) > 0:
m=self.model.objects.get(pk=id)
m.save()
reversion.get_for_object(m).delete()
if len(reversion.get_deleted(self.model).filter(object_id=id)) > 0:
reversion.get_deleted(self.model).get(object_id=id).delete()
I then use it as follows:
> my_execute=Execute(MyModel) m=MyModel.objects.get(pk=id)
>
> --modify something in m--
> my_execute.update(tm)
>
> --modify something else in m--
> my_execute.update(tm)
>
> --modify something else in m--
> my_execute.update(tm)
>
> my_execute.discard(tm) <-- Revert m to original
> or
> my_execute.save(tm) <-- Save new modifications
This works perfectly when I run these via shell, but is inconsistent when running through POST requests in views.
On debugging, I found out that basically when running in shell, every time my registered model is doing a "save()", I see the list "reversion.get_for_object(m)" adding a new revision as expected. But when I run the same through Django view, the list does not get updated as expected, but seems to happen only when the end of view code is reached.
eg: When I update an existing model, I expect to see two entries like:
>>> reversion.get_for_object(tm)
[]
>>> tm_execute.update(tm)
>>> reversion.get_for_object(tm)
[<Version: QGE__Power Sequencing fix__726__lalitb>, <Version: QGE__Power Sequencing fix__726__lalitb>]
>>>
However when I do the same using views:
from collabgrid.testmatrix.models import Testmatrix, Testcaseinfo, Product
from django.http import HttpResponse
from django.utils import simplejson
import json, pdb, datetime, reversion
class Execute:
model = None
delete_ids = []
def __init__(self, model):
self.model = model
if not reversion.is_registered(model):
reversion.register(model)
def update(self, n):
id = n.pk;
if len(self.model.objects.filter(pk=id)) > 0:
m= self.model.objects.get(pk=id)
if len(reversion.get_for_object(m)) == 1: # Update newly inserted element
reversion.get_for_object(m).delete() # reversion list only 1 long.
with reversion.create_revision():
m=n
m.save()
else: # Update existing element. reversion list will be at least 2 long
if len(reversion.get_for_object(m)) == 0: # Add self as first revision.
with reversion.create_revision():
m.save()
with reversion.create_revision(): # Add updates
m=n
m.save()
def insert(self, n):
with reversion.create_revision():
n.pk = None
n.save()
return n.pk
def delete(self, n):
id = n.pk
if len(self.model.objects.filter(pk=id)) > 0:
m=self.model.objects.get(pk=id)
with reversion.create_revision():
m.save()
delete_ids.append(id)
m.delete()
def discard(self, n):
id = n.pk
if len(self.model.objects.filter(pk=id)) > 0:
m=self.model.objects.get(pk=id)
rev=reversion.get_for_object(m)
if len(rev) == 0:
return
if len(rev) == 1: #insert operation, then delete
m.delete()
else: #update operation, then revert
rev[len(rev)-1].revert()
rev.delete()
if len(reversion.get_deleted(self.model).filter(object_id=id)) > 0:
reversion.get_deleted(self.model).get(object_id=id).revert()
def save(self, n):
id = n.pk
if len(self.model.objects.filter(pk=id)) > 0:
m=self.model.objects.get(pk=id)
m.save()
reversion.get_for_object(m).delete()
if len(reversion.get_deleted(self.model).filter(object_id=id)) > 0:
reversion.get_deleted(self.model).get(object_id=id).delete()
tm_execute=Execute(Testmatrix)
def update_sub_col(request):
print request
if request.method == 'POST':
ret = request.POST
tm_data = json.loads(request.POST['tm_data'])
for t in tm_data:
if(len(Testmatrix.objects.filter(pk=t['id'])) > 0):
tm = Testmatrix.objects.get(pk=t['id'])
if tm.os != t['sub_col']:
tm.os = t['sub_col']
print "BEFORE: ", reversion.get_for_object(tm) # List returns as empty []
tm_execute.update(tm)
print "AFTER: ",reversion.get_for_object(tm) # List returns as empty []
# but subsequent read has one
# revision entry.
json_response = {
'ret': 'success'
}
return HttpResponse(simplejson.dumps(json_response),mimetype='application/javascript')
I see the list to be only one long on subsequent reads:
[<Version: QGE__Power Sequencing fix__726__lalitb>]
At this point the model commits all modifications and there is no way to revert them back. Not sure why the difference since I'm using the same code in both cases.
I even used pdb to check the revision list contents after
with reversion.create_revision():
m.save()
and it was empty when I walked through the update function when run via views, but was correctly showing revision entries when debugged through shell prompt.
