I use SQLFORM.smartgrid to show a list of records from a table (service_types). In each row of the smartgrid there is a delete link/button to delete the record. I want to executive some code before smartgrid/web2py actually deletes the record, for example I want to know if there are child records (services table) referencing this record, and if any, flash a message telling user that record cannot be deleted. How is this done?
db.py
db.define_table('service_types',
Field('type_name', requires=[IS_NOT_EMPTY(), IS_ALPHANUMERIC()]),
format='%(type_name)s',
)
db.define_table('services',
Field('service_name',requires=[IS_NOT_EMPTY(),IS_NOT_IN_DB(db,'services.service_name')]),
Field('service_type','reference service_types',requires=IS_IN_DB(db,db.service_types.id,
'%(type_name)s',
error_message='not in table',
zero=None),
ondelete='RESTRICT',
),
Field('interest_rate','decimal(15,2)',requires=IS_DECIMAL_IN_RANGE(0,100)),
Field('max_term','integer'),
auth.signature,
format='%(service_name)s',
)
db.services._plural='Services'
db.services._singular='Service'
if db(db.service_types).count() < 1:
db.service_types.insert(type_name='Loan')
db.service_types.insert(type_name='Contribution')
db.service_types.insert(type_name='Other')
controller
def list_services():
grid = SQLFORM.smartgrid(db.services
, fields = [db.services.service_name,db.services.service_type]
)
return locals()
view
{{extend 'layout.html'}}
{{=grid}}
There are two options. First, the deletable argument can be a function that takes the Row object of a given record and returns True or False to indicate whether the record is deletable. If it returns False, the "Delete" button will not be shown for that record, nor the delete operation be allowed on the server.
def can_delete(row):
return True if [some condition involving row] else False
grid = SQLFORM.smartgrid(..., deletable=can_delete)
Second, there is an ondelete argument that takes the db Table object and the record ID. It is called right before the delete operation, so to prevent the delete, you can do a redirect within that function:
def ondelete(table, record_id):
record = table(record_id)
if [some condition]:
session.flash = 'Cannot delete this record'
redirect(URL())
grid = SQLFORM.smartgrid(..., ondelete=ondelete)
Note, if the grid is loaded via an Ajax component and its actions are therefore performed via Ajax, using redirect within the ondelete method as shown above will not work well, as the redirect will have no effect and the table row will still be deleted from the grid in the browser (even though the database record was not deleted). In that case, an alternative approach is to return a non-200 HTTP response to the browser, which will prevent the client-side Javascript from deleting the row from the table (the delete happens only on success of the Ajax request). We should also set response.flash instead of session.flash (because we are not redirecting/reloading the whole page):
def ondelete(table, record_id):
record = table(record_id)
if [some condition]:
response.flash = 'Cannot delete this record'
raise HTTP(403)
Note, both the deletable and ondelete arguments can be dictionaries with table names as keys, so you can specify different values for different tables that might be linked from the smartgrid.
Finally, notice the delete URLs look like /appname/list_services/services/delete/services/[record ID]. So, in the controller, you can determine if a delete is being requested by checking if 'delete' in request.args. In that case, request.args[-2:] represents the table name and record ID, which you can use to do any checks.
From Anthony's answer I chose the second option and came up with the following:
def ondelete_service_type(service_type_table, service_type_id):
count = db(db.services.service_type == service_type_id).count()
if count > 0:
session.flash = T("Cant delete")
#redirect(URL('default','list_service_types#'))
else:
pass
return locals()
def list_service_types():
grid = SQLFORM.smartgrid(db.service_types
, fields = [db.service_types.type_name, db.services.service_name]
, ondelete = ondelete_service_type
)
return locals()
But, if I do this...
if count > 0:
session.flash = T("Cant delete")
else:
pass
return locals()
I get this error:
And if I do this:
if count > 0:
session.flash = T("Cant delete")
redirect(URL('default','list_service_types#')) <== please take note
else:
pass
return locals()
I get the flash error message Cant delete but the record appears deleted from the list, and reappears after a page refresh with F5 (apparently because the delete was not allowed in the database, which is intended).
Which one should I fix and how?
Note
If any of these issue is resolved I can accept Anthony's answer.
Related
For my web app I have some variables being injected into the base/all templates with the following code:
#app.context_processor
def inject_into_base():
# If user is not logged in
if not current_user.is_authenticated:
# Set count to none
count = None
role = None
# Else Count is set to the number of unread messages
else:
count = db.session.query(message).filter(message.user_id_to == current_user.user_id).filter(message.status == False).count()
role = db.session.query(user_society_role.role_id).filter_by(user_id=current_user.user_id).order_by(user_society_role.role_id.desc()).first().role_id
return dict(count=count, role=role)
All is well until I hit a certain route that contains the line:
Survey.q9 = Survey.q9.split(',')
Which just simply splits the string into a list. It results in
sqlalchemy.exc.InterfaceError: <unprintable InterfaceError object>
If I hard code the two db.session.query's found in inject_into_base it will run just fine, and if I comment out the .split(', ') in the route it also works fine.
I have also found assigning anything to Survey.q9 breaks my app, and ONLY on this one certain route.
Any help is much appreciated, this is my first time asking a question on here so please go easy on me :)
Fixed my issue, turns out sqlalchemy's autoflush feature was breaking my app, all I had to do to fix this was add db = SQLAlchemy(app, session_options={"autoflush": False}) to my __init__.py
Ok this one should be an easy question id imagine, but cannot figure it out.
Im passing form data to the controller and attempting to do a data search there, which in turn, runs this..
def initLogin():
userName = request.vars.user_name;
counter = db(db.Users.UserName == userName).count()
if counter > 0:
return DIV("User exists")
return DIV("user does not exist")
I have checked the value is being passed correctly( which is is) by returning userName instead of the string, which shown me it was the correct value, and when i had a direct string of a correct username, it seemed to work. So my question is.. how do you run a count() function with web2py databases correctly using variables?
Your code is correct and shouldn't be giving you any problems, the only possible problem should be in your userName var not being what you expected or an incorrect sql query. I recommend that you try changing your controller to:
def initLogin():
userName = request.vars.user_name;
counter = db(db.Users.UserName == userName).count()
lastExecutedQuery = db._lastsql
return DIV( lastExecutedQuery )
And check if the query being performed is the one that you expected.
I have the following Django Model:
class State(models.Model):
name = models.CharField(max_length=80,null=False)
latitude = models.CharField(max_length=80,null=False)
longitude = models.CharField(max_length=80,null=False)
def __unicode__(self):
return self.name
In my views.py file I've created the following method:
def getCoords(request):
if request.is_ajax():
if request.method == 'POST':
try:
state = request.POST['state'] #receives the state from JS
stateInstance = State.objects.get(name=state)
stateLat = stateInstance.latitude
stateLong = stateInstance.longitude
data = {"lat" : stateLat, "long" : stateLong}
except State.DoesNotExist:
return HttpResponse("No record")
return HttpResponse(simplejson.dumps(data)) #returns json
So I'm sending this method a param through ajax, let's say "California". The state variable gets the value (I have proved that) but the query doesn't get executed, it returns the query doesn't match message. I've tried with the following as well:
state = request.POST['state']
if state == 'California':
return HttpResponse("Yes!")
else:
return HttpResponse(state)
When this snippet returns the state it displays California which means state's value is correct but the query is not executed properly. I don't know what's going on. Any thoughts?
Make sure you're connecting to the correct database in your settings.py. Make sure the record actually does exist with plain old SQL.
SELECT * FROM [app_name]_state WHERE name = 'California';
Also, try it from the Django shell. python manage.py shell
>>> from [app_name].models import State
>>> s = State.objects.get(name='California')
>>> s
<State: California>
Make sure that what is actually being sent is sent as POST, and not accidentally a GET variable in the URL. Also, make sure that the post variable has no extra characters and that it is actually valid. A decent way to do that is to just print it to the console, or if AJAX, with Firebug.
# Single quotes added so you can see any extra spaces in the console
print "'%s'" % state
I am creating a list from some of the model data but I am not doing it correctly, it works but when I refresh the page in the broswer reportResults just gets added to. I hoped it would get garbage collected between requests but obviously I am doing something wrong, any ideas anyone??
Thanks,
Ewan
reportResults = [] #the list that doesn't get collected
def addReportResult(fix,description):
fix.description = description
reportResults.append(fix)
def unitHistory(request,unitid, syear, smonth, sday, shour, fyear, fmonth, fday, fhour, type=None):
waypoints = Fixes.objects.filter(name=(unitid))
waypoints = waypoints.filter(gpstime__range=(awareStartTime, awareEndTime)).order_by('gpstime')[:1000]
if waypoints:
for index in range(len(waypoints)):
...do stuff here selecting some waypoints and generating "description" text
addReportResult(waypointsindex,description) ##append the list with this, adding a text description
return render_to_response('unitHistory.html', {'fixes': reportResults})
You are reusing the same list each time, to fix it you need to restructure your code to create a new list on every request. This can be done in multiple ways and this is one such way:
def addReportResult(reportResults, fix,description):
fix.description = description
reportResults.append(fix)
def unitHistory(request,unitid, syear, smonth, sday, shour, fyear, fmonth, fday, fhour, type=None):
reportResults = [] # Here we create our local list that is recreated each request.
waypoints = Fixes.objects.filter(name=(unitid))
waypoints = waypoints.filter(gpstime__range=(awareStartTime, awareEndTime)).order_by('gpstime')[:1000]
if waypoints:
for index in range(len(waypoints)):
# Do processing
addReportResult(reportResults, waypointsindex, description)
# We pass the list to the function so it can use it.
return render_to_response('unitHistory.html', {'fixes': reportResults})
If the addReportResult stays small you could also inline the description attribute set by removing the call to addReportResult altogether and doing the waypointsindex.description = description at the same position.
Just so you're aware of the life cycle of requests, mod_wsgi will keep a process open to service multiple requests. That process gets recycled every so often but it is definitely not bound to a single request as you've assumed.
That means you need a local list. I would suggest moving the addReportResult function contents directly in-line, but that's not a great idea if it needs to be reusable or if the function is too long. Instead I'd make that function return the item, and you can collect the results locally.
def create_report(fix, description): # I've changed the name to snake_casing
fix.description = description
return fix
def unit_history(request,unitid, syear, smonth, sday, shour, fyear, fmonth, fday, fhour, type=None):
reports = []
waypoints = Fixes.objects.filter(name=(unitid))
waypoints = waypoints.filter(gpstime__range=(awareStartTime, awareEndTime)).order_by('gpstime')[:1000]
if waypoints:
for index in range(len(waypoints)):
report = create_report(waypointsindex, description)
reports.append(report)
return render_to_response('unitHistory.html', {'fixes': reportResults})
Excuse the vague title, I didn't know how else to state this.
I have a task worker request handler that fetches data from a URL and writes it to blobstore and saves the data's blob_key to a ListProperty in datastore. I've tried to simplifly the code for clarity here:
class Fetch(webapp2.RequestHandler):
def get(self):
url = self.request.get('url')
itemKey = self.request.get('itemKey')
item = MyModel.get(itemKey)
try:
result = urlfetch.fetch(url=url)
if result.status_code == 200:
saveDataResult = save_data(result.content, itemKey)
if saveDataResult is False:
raise Exception('error saving data')
else:
raise Exception('error fetching data: %s' % result.status_code)
item.status = 'success'
except Exception:
item.status = 'failed'
finally:
item.put()
def save_data(data, itemKey)
try:
#write data to blobstore and get its blob_key...
blob_key = files.blobstore.get_blob_key(file_name)
item = MyModel.get(itemKey)
item.blobKey.append(blob_key)
item.put()
return True
except:
return False
Now the problem I'm having is, when saveDataResult returns True, its status is set to 'success' but its blobKey property contains no value, even though a blob_key was generated and the data successfully written. I can't see what's causing this to save my life, please help.
Without much more information it is very difficult to determine what's happening. Here's my educated guess:
MyModel.get(itemKey) is called both in get() and save_data(). I surmise that it's returning two different objects representing the item. When the blobKey gets updated in save_data, the update is occurring only in the object fetched in save_data. When you later examine it outside that scope, you're looking at a different object.
Whether this is correct or not will depend on the implementation of MyModel.get().
Also, you do realize that you're calling item.put() twice, right?
The problem is here
finally:
item.put()
this single call overrides the data saved by save_data() because it references an older object of item.
My suggestion would be you do the status updates from save_data() i.e item.status = 'success'
or move item = MyModel.get(itemKey) to come after save_data() so you can fetch the updated object.
The problem is that when you call save_data() with item = MyModel.get(itemKey)
which is again called from the class Fetch you end up having two different objects and therefore overwriting the one in save_data() and hence when you go to your model datastore no data for blobkey is stored as its overwritten.
Try doing everything in the class or you do not use item = MyModel.get(itemKey) twice.