I am trying to pass some information between SavingChangesAsync and SaveChangesInterceptor the issue is that whenSavingChanges is executed new entities have unknown Id, but then when SavedChangesAsync is exetued all temporary properties became final and ids are known. The issue is how to pass data between those methods.
My main concern is it possible that there will be another invokation of SavingChangesAsync before SavedChangesAsync is executed in SaveChangesInterceptor? If yes then I can't use an object field which will be cleared after each SavedChangesAsync.
Related
Is it considered bad practice to pass whole objects to meteor methods and should I stick to just passing the ID, and then using the passed Id to fetch the document from within the meteor method instead?
The main consideration here is security: if your method is expecting to be passed an object, a Meteor-savvy user can call it from the console, passing any object of their choosing as the argument, whether it's in your DB or not, thereby bypassing any DB schema/validation you have set up. In order to avoid that, you need to be looking the object up in the DB in your server-side method code, which rather defeats the point of passing in the whole object rather than just the id in the first place. So, in summary, pass the id rather than the object.
If the user should be able to call your method with an arbitrary object, then I'd argue that you absolutely should be passing the whole object rather than just the id as otherwise you're necessitating storing a document in the database purely so that you can call a method on it, which is ugly. However, I think that would be a fairly unusual situation.
I need a help for while creating the collection the below error is came in server console.How to solve the error ?
Error:
Warning: creating anonymous collection. It will not be saved or synchronized over the network. (Pass null for the collection name to turn off this warning.)
TLDR: you need to provide a collection name as an argument when you create a shared collection.
In most cases, you want to provide a name as a parameter when you define a collection:
Docs = new Meteor.Collection('docs');
When you don't, you create anonymous collection:
Items = new Meteor.Collection();
In the first case, the collection is shared and synchronized between client and server, and the name you've provided is used as a table name in order to store the collection in Mongo.
Anonymous collections are local in the place they've been created. Their contents are never synchronized. Therefore, even if you create such collection in a piece of code that will be run on the server and on the client, those two collections will be separate things: data created on the server won't be visible on client, data created on the client won't be visible on server, and both won't be stored in the database.
There are legitimate use cases for anonymous collections, mostly on the client side when you need to create some temporary data, but want to retain all the benefits of Minimongo and reactivity. However, it's one of those things that are needed rarely and you really do know when you need to do it. It's more probable that a beginner made a mistake and forget to provide the collection name when he wanted to create a typical shared collection. Therefore, the system issues a warning to make sure that you really wanted to do what you just did.
Therefore:
If your goal was to create an anonymous collection, and you know what you're doing, don't worry about that message. It's just a warning, the code will be functional and do what it's told to.
If you wanted to create a normal collection, or are just starting out and don't know what's this all about, just add a parameter to your collection definition.
I have an existing web application that uses EF and POCO objects. I want to improve the client experience by exposing some of my objects through WCF(JSON). I have this working fine but where I am unsure is how to handle derived objects(not sure if that is the correct term) or IEnumerable anonymous objects if you will.
Let's say I have 3 tables structured like so:
Templates
ID
Template
Groups
ID
Group
Instances
ID
TemplateID
GroupID
This is obviously a one-to-many type relationship. I have my navigation properties setup correctly and getting strongly typed object properties works great. However, how do I send serialized anonymous type object(s) over the wire. Like an object that sends all instances that are equal to groupid=1 and include the names of the template and the object.
Am I missing something or do I have to create another class object for WCF that would look like this:
WCF Object
InstanceID
TemplateID
TemplateName
GroupID
GroupName
I guess I could alter my tables to account for this but that seems wrong too. I know that IEnumerable objects can't be serialized and I know that throw away objects are probably not the way to go either. I want to do this the right way but I am not sure how to go about it.
Your suggestions are appreciated.
Regards
Based on what you're doing, I'd suggest looking at OData with WCF Data Services. You state that you want to be able to send all instances where the groupid=1 - OData is great at this type of filtering.
If you're want to stick with your current approach and not use OData, then my first question is why are you sending back anonymous types at all? You can do what you are seeking (all instances with a groupid=1) without sending back an anonymous type. In your select clause you just create new instances of your concrete objects rather than newing up anonymous types. If your query is really just filtering and not executing any meaningful projection with the selct to anonymous type, then I don't see any reason to send back your anonymous type at all.
Is it possible to store instances of a class in a cookie or in shared objects.
Basically in my application I have an object "Diagram" that the user can create. If they hit save, I want to store the current instance as a cookie and allows them to reload it later.
Alternatively, I could see about getting them to store the saved version on the hard disk. But even then, all I want to save and retreive is my actionscript object.
Is this possible?
I've tried storing the object to SharedObject.data.diag, but when I try to retrieve the object from the cookie doing SharedObject.data.diag as Diag returns null.
http://www.oreilly.de/catalog/9780596529857/chapter/ch17.pdf
Page 10: Serialize typed objects.
You may have issues with deep cloning if you have a complex class.
I'm currently building the client side of a Flex/PHP project using the Presentation Model pattern.
What I'm trying to achieve:
I currently have a view displaying non-editable information about a domain object called Node. Depending on if the Node is editable and the user has the right privileges, an additional view becomes available where it's possible to make changes to this object. Any changes made are only committed to the server once the user decides to "Save Changes". If changes are made to a NodeA and the user navigates away to a different NodeB without saving them, NodeA is reverted to its original state.
Design:
I have a PM for the info view holding a reference to the current Node. The PM for the edit view is extended from this info PM, adding methods to make changes to the wrapped Node object. Both PMs has the same Node reference injected into them and all fields in the info/edit views are bound to the Node via their PMs.
The problem:
When the user makes changes to NodeA but doesn't commit them, I can't seem to think of an elegant solution to revert back to the original state. Basically, what I've thought of so far is to hold separate value copies on the edit PM, either clone-creating a new Node reference or through an identical set of Node properties. Of these two the former seems like the better idea because the Node already houses domain logic, but I wonder whether creating clones of unique domain objects is a bad practice, even if it's used in a limited scope.
I handle similar cases by storing the original data in an XML property of the Value Object ("VO"), and reset all of the other property values when the VO is needed.
So, when it is first needed to be viewed, I go get the XML:
<Node>
<prop1>value</prop1>
<prop2>value</prop2>
<prop3>value</prop3>
<prop4>value</prop4>
</Node>
When I retrieve the XML, in my result handler, the first thing I do is create an instance of my VO, and set the XML property, and then call a public function in a separate class to set the VO's properties:
private function getNodeResultHandler(event:ResultEvent):void
{
var myNode:Node = new Node();
myNode.xmlData = new XML(event.result);
nodeUtils.setNodeProperties(myNode);
}
public class nodeUtils
{
public function setNodeProperties(node:Node):void
{
var nodeXmlData:XML = node.xmlData;
myNode.prop1 = nodeXmlData.prop1;
myNode.prop2 = nodeXmlData.prop2;
myNode.prop3 = nodeXmlData.prop3;
myNode.prop4 = nodeXmlData.prop4;
}
}
Then, any time you switch your view to edit mode, you call that same function to reset the properties to the values stored in the XML.
The only other thing you need to do is reset that XML any time the user commits changes to the VO. I usually handle this by passing back the VO's data in the same format on a Save and Get, and then saving the XML just as above.
I usually do this in a Cairngorm MVC application, so I have event/command chains to handle all of this, but you can put this functionality in any number of classes, or in the VO class itself, whichever is easiest for you to maintain.
Each view should have it's own instance of your Presentation Model class. Just maintain it in memory if the user has not saved it when moving to another view. Cloning accomplishes basically the same thing through a more convoluted process.