I'm pretty new to Symfony2 and I'm trying to get to grips with how and when to pass dependencies / app parameters and have got into a muddle with how to insert parameters into an entity.
The situation is that I have an entity which will contain strings of uploaded file names and I want to pass through the parameters of the directory location (where the uploaded file will be stored) which I have set in app/config.yml. Which is basically similar to http://symfony.com/doc/2.0/cookbook/doctrine/file_uploads.html but with the paths defined in app/config.yml rather than hard coded into the entity.
First off I thought this could be done via the constructor, but this only seems fine for new objects and not when they are pulled out the repository? (as the constructor is not called then) so I don't know how you're supposed to pass the dependencies to the entites.
Any guidance much appreciated.
I think this problem should be solved by adding a listener for onLoad (and maybe onPersist, not sure) events.
In the entity add a setUploadPath($path) method, which you will call with the listener.
In order to actually have the path parameter in the listener you can pass it as constructor argument when setting up the listener service.
Related
I have a command object that I want to convert into a domain object.
However, the object I want to convert the command object into may be one of two domain classes (they're both derived classes), and I need to do it in a service (which is where, based on other data, I decide which type of object it should be bound to). Is this possible and what's the best way to do this? bindData() only exists in a controller.
Do I just have to manually map command object parameters to the appropriate domain object properties? Or is there a faster/better way?
If the parameters have the same name, then you can use this question to copy the values over. A quick summary can be as follows.
Using the Grails API
You can cycle through the properties in a class by accessing the properties field in the class.
object.properties.each { property ->
// Do something
}
You can then check to see if the property is present in the other object.
if(otherObject.hasProperty(property) && !(key in ['class', 'metaClass']))
Then you can copy it from one object to the other.
Using Commons
Spring has a really good utility class called BeanUtils that provides a generic copy method that means you can do a simlple oneliner.
BeanUtils.copyProperties(object, otherObject);
That will copy values over where the name is the same. You can check out the docs here.
Otherwise..
If there is no mapping between them, then you're kind of stuck because the engine has no idea how to compare them, so you'll need to do it manually.
I just created a custom template for all elements with an FunctionPickerAttribute (custom attribute that I wrote myself). Now, what the FunctionPickerAttribute does is simply to store the name of a method that returns a IEnumerable<KeyValuePair<String, String>>.
The template I created finds that attribute, finds the method (using reflection) and is then supposed to call that method upon the object. However, the problem is that FunctionPickerAttribute is assigned onto a property of type string, so that when I enter the FunctionPicker-template I have no idea of how to get a reference to my object.
I can find the type of the Container (using ViewData.ModelMetadata.ContainerType), but I need to get a reference to the Container in some way. Is this possible? And if it is, how do I go about making it?
Not the way your doing it.
The only way to get the container is pass the entire model to your template.
If you post more of your code I could help better. I do this type of thing often.
I'm working on my first ASP.NET MVC (beta for version 3) application (using EF4) and I'm struggling a bit with some of the conventions around saving a new record and updating an existing one. I am using the standard route mapping.
When the user goes to the page /session/Evaluate they can enter a new record and save it. I have an action defined like this:
[ActionName("Evaluate")]
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult EvaluateSave(EvaluteSessionViewModel evaluatedSession)
{
}
When they save I grab an entity off the view model and attach it to my context and save. So far, so good. Now I want the user to be able to edit this record via the url /session/Evaluate/1 where '1' is the record ID.
Edit: I have my EF entity attached as a property to the View Model.
If I add an overloaded method, like this (so I can retrieve the '1' portion automatically).
[ActionName("Evaluate")]
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult EvaluateSave(ID, EvaluteSessionViewModel evaluatedSession)
{
}
I get an "The current request for action 'Evaluate' on controller type 'SessionsController' is ambiguous between the following action" error. I'm not sure why they're ambiguous since they look unique to me.
I decided that I was just going to skip over this issue for now and see if I could get it to update an existing record, so I commented out the EvaluateSave that didn't have the ID parameter.
What I'd like to do is this:
// Load the original entity from EF
// Rebind the postback so that the values posted update the entity
// Save the result
Since the entity is populated as the parameter (evaluatedSession) the rebinding is happening too soon. But as I look at the approach I'd like to take I realized that it opens my code up to hacking (since a user could add in fields into the posted back page and these could override the values I set in the entity).
So it seems I'm left with having to manually check each field to see if it has changed and if it has, update it. Something like this:
if (evaluatedSession.MyEntity.myField <> savedSession.myField)
savedSession.myField = evaluatedSession.MyEntity.myField;
Or, save a copy of the entity and make sure none of the non-user editable ones have changed. Yuck.
So two questions:
First: how do I disambiguate the overloaded methods?
Second: is there a better way of handling updating a previously saved record?
Edit: I guess I could use something like Automapper...
Edit 9/22/2010 - OK, it looks like this is supposed to work with a combination of two items: you can control what fields bind (and specifically exclude some of them) via the [Bind(Exclude="field1,field2")] attribute either on the class level or as part of the method doing the saving, ex.
public ActionResult EvaluateSave([Bind(Exclude="field1")] EvaluateSessionViewModel evaluatedSession)
From the EF side of things you are supposed to be able to use the ApplyCurrentValues() method from the context, ex.
context.ApplyCurrentValues(savedEval.EntityKey.EntitySetName, evaluatedSession);
Of course, that doesn't appear to work for me. I keep getting "An object with a key that matches the key of the supplied object could not be found in the ObjectStateManager. Verify that the key values of the supplied object match the key values of the object to which changes must be applied.".
I tried attaching the original entity that I had just loaded, just in case it wasn't attached to the context for some reason (before ApplyCurrentValues):
context.AttachTo(savedEval.EntityKey.EntitySetName, savedEval);
It still fails. I'm guessing it has something to do with the type of EF entity object MVC creates (perhaps it's not filled in enough for EF4 to do anything with it?). I had hoped to enable .NET framework stepping to walk through it to see what it was attempting to do, but it appears EF4 isn't part of the deal. I looked at it with Reflector but it's a little hard for me to visualize what is happening.
Well, the way it works is you can only have one method name per httpverb. So the easiest way is to create a new action name. Something like "Create" for new records and "Edit" for existing records.
You can use the AntiForgeryToken ( http://msdn.microsoft.com/en-us/library/dd492767.aspx ) to validate the data. It doesn't stop all attempts at hacking but it's an added benefit.
Additional
The reason you can only have one action name per httpverb is because the model binders only attempt to model bind and really aren't type specific. If you had two methods with the same action name and two different types of parameters it can't just try and find the best match because your intent might be clearly one thing while the program only sees some sort of best match. For instance, your might have a parameter Id and a model that contains a property Id and it might not know which one you intend to use.
I've been learning the ASP.NET MVC framework using the Apress book "Pro ASP.NET MVC Framework" by Steven Sanderson. To that end I have been trying out a few things on a project that I am not that familar with but are things that I thing I should be doing, namely:
Using repository pattern to access my database and populate my domain/business objects.
Use an interface for the repository so it can be mocked in a test project.
Use inversion of control to create my controllers
I have an MVC web app, domain library, test library.
In my database my domain items have an Id represented as an int identity column. In my domain classes the setter is internal so only the repository can set it.
So my quandries/problems are:
Effectively all classes in the domain library can set the Id property, not good for OOP as they should be read-only.
In my test library I create a fake repository. However since it's a different assembly I can't set the Id properties on classes.
What do others do when using a database data store? I imagine that many use an integer Id as unique identifier in the database and would then need to set it the object but not by anything else.
Can't you set your objects' IDs during construction and make them read-only, rather than setting IDs through a setter method?
Or do you need to set the ID at other times. If that's the case, could you explain why?
EDIT:
Would it be possible to divorce the ID and the domain object? Does anything other than the repository need to know the ID?
Remove the ID field from your domain object, and have your repository implementations track object IDs using a private Dictionary. That way anyone can create instances of your domain objects, but they can't do silly things with the IDs.
That way, the IDs of the domain objects are whatever the repository implementation decides they are - they could be ints from a database, urls, or file names.
If someone creates a new domain object outside of the repository and say, tried to save it to your repository, you can look up the ID of the object and save it as appropriate. If the ID isn't there, you can either throw an exception to say you need to create the object using a repository method, or create a new ID for it.
Is there anything that would stop you from using this pattern?
you can use the InternalsVisibleTo attribute. It will allow the types from an assembly to be visible from the tests (provided they are in different assemblies).
Otherwise you can leave the property read-only for the external objects but in the same time have a constructor which has an ID parameter and sets the ID property. Then you can call that constructor.
Hope this helps.
I've created a object that I'd like to have accessible from wherever the request-object is accessible, and to "die" with the request, more or less like how you always in a mvc-application has access to the RouteData-collection. Especially it's important that I have access to this object in the execution of action-filters. And also there need to be created a new object of my class whenever a new request is made to the page (the object needs to be request-safe, ie. only one request modifies that one object).
Any thoughts about how to achieve this?
HttpContext is a good place for this. The Items dictionary could be used to store objects relative to the request.