I'm new to #ngrx/data and trying to understand how I can override the reducer & actions.
My current problem could be solved in other ways like adding an extra method, reducer & action but I would probably need this answer in the future.
The problem is that my delete call should just set the item to "hidden" in the store and not to delete it.
This is the set-up I'm using: https://stackblitz.com/edit/ngrx-data-tutorial
Related
So I know I can put search_auto_update = False on the Model in question, however I dont want to turn off indexing entirely.
https://docs.wagtail.org/en/v2.13.5/topics/search/indexing.html#disabling-auto-update-signal-handlers-for-a-model
I have a command which bulk syncs data from an API. Currently, on every Save, it's also triggering and index; this is inefficient and slow. It would make a lot more sense to disable indexing during the sync and then bulk-index the items at the end.
Is this possible? I tried setting search_auto_update as an key/value on the model before save, but it didn't seem to do anything (it looks like it needs to be an attribute on the class, rather than a model instance value).
The search indexing on save is done via signals, so I think this SO answer for how to temporarily disable signals should work. In short, use FactoryBoy's mute_signals decorator
So, we all know that you can add events post-render by calling Template.templateName.events() and passing in new events. My question is: How do I remove them? I've found that I'm adding them how I like, but I end up with several of the same event, that all fire, and it's causing all sorts of problems. Is there a specific place that meteor stores the actual events? Where I could clear them out?
Template events should not be called several times but used once for static event definitions for this template that every instance of the template will listen to.
The documentation is not very helpful here. However, if you need dynamic template events you are still in good hands using the classic addEventListener or jQuery on and use bind to bind them to the template instance.
Don't forget to remove them when required but at least in Template#onDestroyed
I found that Template.templateName.__eventMaps = [] did the trick. I run this before creating a new instance of my template, and therefore only get one set of event handlers. woo!
I am banging my head looking at the code for ... quite some time.
I have a lightning event, created from ics (including an alarm).
I want to delete the alarm after something has occurred. I found calItemBase has mAlarms. But how to delete a single alarm? (there should be only one). What is the proper value of mAlarms if there is no alarm?
What to do with mAlarmLastAck and other properties?
My workaround is to recreate from ical without the alarm, but then the user looses categories and other things he set for the event in the UI.
Many thanks,
Klaus
A summary of the methods intended to be public for an item can be seen here: http://mxr.mozilla.org/comm-central/source/calendar/base/public/calIItemBase.idl
Specifically, there is a deleteAlarm method. Example:
var alarms = item.getAlarms({});
item.deleteAlarm(alarms[0]);
If you are sure you want to delete all alarms, you can also use the clearAlarms method.
item.clearAlarms();
I know this question may seem weird but I'd like to get a list of currently dispatched events.
The thing is that I am a lazy man and I would like to check if the 'checkout_cart_add_product_complete' has been fired without creating an observer for it.
So the idea is to get an array of all dispatched events and do an in_array on it :)
I thought that Mage::getEvents()->getAllEvents() would throw some info but it just returns an empty array.
I also digged a bit in lib/Varien/Event files and folders but didn't manage to be successful at creating an observer programmatically. Yep, I know, why being simple while one can be complicated ? :)
So this main question (getting a list of dispatched events) hides another (for the pure knowledge) wich would be "how to create an observer programmatically".
What do you think?
Thanks a lot!
Take a look at dispatchEvent and you'll see that events are only loaded from the assorted config.xml files, via SimpleXML. I cannot see any way to intercept this except to override Mage_Core_Model_App.
Of course there cannot be an event-dispatched-event, that would create an infinite loop, so there is no way to observe all events.
If you need to see events for development my advice would be to set a breakpoint in dispatchEvent with your debugger, that way you get to see not only the event names but also the objects passed as parameters too. I've tried other ways before but this was most convenient for me.
I need to do the same and I think it's possible to trick magento by the function getEventConfig in Mage_Core_Model_Config. You could force him to add automatically a default observer.
There are two classes: User and Question
A user may have many questions, and it also contains a question_count
to record the the count of questions belong to him.
So, when I add a new question, I want update the question_count of the
user. At first, I do as:
question = Question(title='aaa', content='bbb')
Session.add(question)
Session.flush()
user = question.user
### user is not None
user.question_count += 1
Session.commit()
Everything goes well.
But I wan't to use event callback to do the same thing. As following:
from sqlalchemy.orm.interfaces import MapperExtension
class Callback(MapperExtension):
def after_insert(self, mapper, connection, instance):
user = instance.user
### user is None !!!
user.question_count += 1
class Question(Base):
__tablename__ = "questions"
__mapper_args__ = {'extension':Callback()}
....
Note in the "after_insert" method:
instance.user # -> Get None!!!
Why?
If I change that line to:
Session.query(User).filter_by(id=instance.user_id).one()
I can get the user successfully, But: the user can't be updated!
Look I have modified the user:
user.question_count += 1
But there is no 'update' sql printed in the console, and the
question_count are not updated.
I try to add Session.flush() or Session.commit() in the
after_insert() method, but both cause errors.
Is there any important thing I'm missing? Please help me, thank you
The author of sqlalchemy gave me an useful answer in a forum, I copy it here:
Additionally, a key concept of the
unit of work pattern is that it
organizes a full list of all
INSERT,UPDATE, and DELETE statements
which will be emitted, as well as the
order in which they are emitted,
before anything happens. When the
before_insert() and after_insert()
event hooks are called, this structure
has been determined, and cannot be
changed in any way. The
documentation for before_insert() and
before_update() mentions that the
flush plan cannot be affected at this
point - only individual attributes on
the object at hand, and those which
have not been inserted or updated yet,
can be affected here. Any scheme
which would like to change the flush
plan must use
SessionExtension.before_flush.
However, there are several ways of
accomplishing what you want here
without modifiying the flush plan.
The simplest is what I already
suggested. Use
MapperExtension.before_insert() on the
"User" class, and set
user.question_count =
len(user.questions). This assumes
that you are mutating the
user.questions collection, rather than
working with Question.user to
establish the relationship. If you
happened to be using a "dynamic"
relationship (which is not the case
here), you'd pull the history for
user.questions and count up what's
been appended and removed.
The next way, is to do pretty much
what you think you want here, that is
implement after_insert on Question,
but emit the UPDATE statement
yourself. That's why "connection" is
one of the arguments to the mapper
extension methods:
def after_insert(self, mapper, connection, instance):
connection.execute(users_table.update().\
values(question_count=users_table.c.question_count +1).\
where(users_table.c.id==instance.user_id))
I wouldn't prefer that approach since
it's quite wasteful for many new
Questions being added to a single
User. So yet another option, if
User.questions cannot be relied upon
and you'd like to avoid many ad-hoc
UPDATE statements, is to actually
affect the flush plan by using
SessionExtension.before_flush:
class
MySessionExtension(SessionExtension):
def before_flush(self, session, flush_context):
for obj in session.new:
if isinstance(obj, Question):
obj.user.question_count +=1
for obj in session.deleted:
if isinstance(obj, Question):
obj.user.question_count -= 1
To combine the "aggregate" approach of
the "before_flush" method with the
"emit the SQL yourself" approach of
the after_insert() method, you can
also use SessionExtension.after_flush,
to count everything up and emit a
single mass UPDATE statement with many
parameters. We're likely well in the
realm of overkill for this particular
situation, but I presented an example
of such a scheme at Pycon last year,
which you can see at
http://bitbucket.org/zzzeek/pycon2010/src/tip/chap5/sessionextension.py
.
And, as I tried, I found we should update the user.question_count in after_flush
user, being I assume a RelationshipProperty, is only populated after the flush (as it is only this point the ORM knows how to relate the two rows).
It looks like question_count is actually a derived property, being the number of Question rows for that user. If performance is not a concern, you could use a read-only property and let the mapper do the work:
#property
def question_count(self):
return len(self.questions)
Otherwise you're looking at implementing a trigger, either at the database-level or in python (which modifies the flush plan so is more complicated).