I'm looking at creating my first ASP.NET MVC application using MVC3.
The project template I used included some models for registering users, logging in and updating a forgotten password.
I want users to be authenticated against my own data store (probably using Entity Framework) and using google OAuth.
I assumed that I'd want a User model class that contained a few standard properties and some business logic which handled the "local" authentication and the OAuth call but the project template has confused me.
Should I be creating multiple view-models for different actions like Login, Register, etc and then using the controller to instantiate and invoke my model to perform the business logic or should I use my User model for all the different actions?
Thanks
Ben
Should I be creating multiple
view-models for different actions like
Login, Register, etc and then using
the controller to instantiate and
invoke my model to perform the
business logic or should I use my User
model for all the different actions?
View model per view. That's the rule. There might even be 2 view models per view (one for rendering data in the GET and one for receiving data from the view in the POST action). Don't be shy in creating view models. You definitely shouldn't be using a User model for all different actions, that would be catastrophic. The model should be used by your service layer. A User model will be manipulated by this layer, and never passed to a view.
You may also checkout AutoMapper for mapping between your model classes and view models. It's a great tool and comes in handy especially when the number of view models start to increase.
Related
Hi good morning to everyone
currently I am working in spring. I am searching long time to work with session but somebody told use Model And View instead of session which is right way for maintain user status and give some referral link for session tracking.
There is no relation between (Model & view) and session, Both are two different things.
Model and view is used to pass data from controller to view(interaction between controller and view). we need to create different model and view objects for different operations (CRUD operations) in a web application.
In case of session if we wanted to store any object, object type,variables and want to use those for entire application for that particular session. Then we can go for session. This can be done by using annotation of #Scope("session") or we can configure in spring configuration file.
If you want to maintain user details for a particular session you can use session. If your requirement is to show the user details from database in view then you can use Model and view in controller.
From Dynamic Selection Of JsonView in Spring MVC Controller, I understand that you can annotate controllers using #JsonView(...) and also return MappingJacksonValue with the serialization view specified from within the method. Is there a way to globally & dynamically select the serialization view based on the currently logged-in principal? I couldn't use the solution from the linked article because the object, that I wanted to serialized with dynamically different views, is nested inside a list.
To be a little more specific, my use case is: a logged-in user can view other user account details, but cannot view specific attributes like e-mail, circle of friends, etc. unless they are viewing their own account or are already friends with that user. I want to globally be sure that the currently logged-in user cannot view attributes that they are not entitled to by the other user.
Thank you in advance!
I've been doing a lot of tutorials for different MVC frameworks, and it seems very typical for Authorization to take place in the Controller. Why?
My thought is the Controller should only be used to orchestrate Model actions, to handle redirection and to handle error events. These are the things that are dependent on the specific request. Putting Authorization in the Controller seems like you're going to have to duplicate the authorization whenever you're using the same Model action in different Controller actions or different Controllers. If Auth is in the Model, you have consistent requirements for carrying out an action or state change on the data.
I've been googling and looking at other questions such as Should authorization be part of the model or controller? but I don't really see why it's the accepted convention.
Is there a specific reason I'm missing for putting Authorization in the controller over the model?
To sum up points in the comments:
Controllers are responsible for altering the state of the model layer and the current view. Nothing else.
Authorization belongs where an action is being carried out, if you're following a strict MVC pattern this would most likely be the model, and a Controller is certainly not responsible for authorizing the use of model actions.
Cookies should be treated like any other datastore: abstracted and used within the models, not directly by controllers.
Authentication and Authorization are separate issues, though they both usually go in the model layer, because they usually involve checks against values in datastores (such as cookies).
Is there a specific reason I'm missing for putting Authorization in the controller over the model?
Well, the most common reason I can imagine is laziness. I don't mean that morally, it's just far easier to flunge some authorization concept on top into a layer that is more close to the concrete request then to have differentiated access on the model layer. To have authorization with the models is a much higher design.
To add some more practical advice to the answer, I think you should analyse for each program where and for what you would want to introduce authorization. The needs for that can be (extremely) different.
Then only in the next step you should think about which design is most beneficial to introduce authorization and authentication to fulfill these needs.
In an MVC approach, you need to put security in a location where:
it cannot be circumvented
it can be configured, managed and updated easily
This applies - as a matter of fact - to any architecture / type of application.
Specifically, in MVC, imagine you put authorization in the view. For instance you decide to control who can approve a transaction by enabling / disabling a button. A user of your view will not be able to approve a transaction if he/she is not allowed. Imagine now that you expose your controller over an API rather than a view. The approve authorization check now needs to be reimplemented in the API layer.
This example shows you are better off moving authorization away from the view / the different end-points and into a common, central point - your controller.
Similarly, if you want to control access to large sets of data (e.g. medical records), you ideally want to put the authorization in the model. This is both for performance reasons and for security reasons: you'd rather have the controller handle less data and you should always strive to protect as close as possible to the source of the sensitive data.
Note that having authorization hooks / checks in the view, controller, and model at the same time may lead to an altogether enhanced experience. See authorization in the view as a "safety / usability" mechanism whereby a user is only presenetd with those relevant menus and widgets on screen based on their permissions. If they were malicious and knew their way around the UI to the controller, authorization there would still kick in.
Finally, generally speaking, you want to decouple non-functional requirements / logic from functional requirements / logic. Much like you do not implement logging in code but use a configurable framework (e.g. Log4J) or you rely on the container for authentication (e.g. HTTP BASIC in Apache Tomcat), you want to use an externalized authorization framework such as Claims-based authorization in the Microsofct MVC4 world, Spring Security in Java, CanCan in Ruby, or XACML, a standard part of the same body as SAML (OASIS) and which will let you apply authorization to any type of application and any layer.
Authorization as an entire process should be involved in both: Controller and Model layers.
But, all the logc (SQL queries, etc) should definitely happen in the model.
Controller is kind of an intermediate layer between the view (representation) and the Model.
But, you simply cannot throw away the Controller from this scheme, because Controller is responsible for handling Sessions and Cookies. Without these two things all your Authentication/Authorization logic is useless, because it is stateless by its nature. Sessions and Cookies bring state to it.
Moreover, as you correctly mentioned, Controller is responsible for redirects.
Suppose my module accepts a username and password and returns true or false to indicate success or failure. Would this be more a model or a controller?
It really doesn't need to exist in a controller. It could be in a class library if needed. You would need to have a Controller Action / View that eventually prompts a user for their credentials, but the logic of authenticating does not need to exist in the Controller Action.
The username, password and success indicator would be part of the Model,
the model would be made visible to the client in the View,
the model would be processed by the Controller.
Authentication is a service - structure from model layer, which utilizes both domain object and data storage structure (usually data mappers). As minimum, it has to interact with User domain objects and both persistent storage (like SQL) and cookies. It also might require data exchange with session.
Also, when controller sends user login details to model layer, it should not receive any replay. That part should be handles by the current View, which requests the user-state from model layer.
P.S. I hope you are not one of the people who refer to IE as "the internet" and ASP.NET MVC framework as "the MVC".
it will be an action from a controller.
I'm writing a web application with some ACL requirements: a user can make changes to some items, some items may be editable by several users, administrator can edit anything and a manager can edit everything within her organization etc.
I'm using the Play! framework, and by the looks of the Secure module, it seems that the place to put authorization concerns is in the Controllers. However, it seems to me that the authorization issues are part of the business logic, and therefore should be in the model. Furthermore, I'm starting to see duplicated logic in the controllers that I need to refactor out.
On the other hand, adding authorization to the model means that I'd have to have some way of getting the current user from within the model, which doesn't seem right. Alternatively, I could add a "current_user" parameter to every model method, but that seems even worse.
So what is the common practice? Can/should I put authorization code in the model, or keep it in the controller?
I think this is a grey area. One could argue that the user access is part of the mapping between the HTTP world and the Object-Oriented world. This is what the controller is intended for (hence the heavy use of statics), to transform the incoming request, ready to process the business rules on the domain model.
I would suggest that the controller logic is absolutely the right place for controlling the access to the model, especially as this is managed largely at an annotation level, and the authentication is abstracted off to a Security class.
Authorization should neither be part of controller or domain model.
Instead it should be in the service layer.
Controller should just act as dispatcher and delegate between HTTP and application service.
It's the application service where the orchestration takes place. This is the best place for placing authorization.
Suppose user A is authorized to access data from domain X, but not authorized for even a read access for data from domain Y. If authorization is placed in the controller, then user A gets authorized in the controller X, and via the service calls can access data from domain Y, which is not what we expected.
Since domain models communicate with each other on service layer, hence it best to place the authorization on the same level.
In most cases, the security should be one (or more) layer above the Model. Security is a domain on it's own, restricting access to a lower level layer.
I don't think the security should be done at the controller level.
In my opinion, this should look like that:
View -> Controller -> Security -> Model
The security layer could be a façade or a proxy over the model, protecting access, but be transparent to the controller.
However, if the views are to be modified depending on the access rights of the user, some checks might have to happen at the controller level (like setting the value of a CanEdit boolean property on the ViewModel).
I personally really like the way the Play! Secure module handles this (the tutorial is ever-helpful here). If you don't mind using the #Before annotation, it's pretty painless.
I am at this stage and intending to handle this in the following way:
No form validation by JS, instead via HTTPS ajax
An Ajax php class
Form data sent to a model as its data for concrete validation for
common type such as email and password (likely assoc array validation will be reused by other classes so this is definately a model area).
if no error a lookup in a User table for the credentials email /
password credentials passed to a Controller with the authentication
type such as login / signup / password reset
the controller then produces the required output view or sets user logged in session etc
This is based in Laravel but I have my own library as want it independent of laravel and just loosely based for this vital requirement.
The point being that the Model looks up the required credentials as data, then sends to the Controller as it does not care how it should be processed. I think this is the only way to make this area a definitive responsibility between each of the components.
From my personal experience with MVC frameworks I would say:
Model is an object that is representing database table it should be
pure and should not contain any additional logic.
Controller is the place where are made the decisions and other
custom logic, so the authorization should be in the controller. It
could be designed some hook that can check if the user is authorized
or not in all needed places so you wont have a code repetition DRY.
The best way to give permission to user if you are using a typical
REST architecture is to make a token , save it in the databse and on
client side and verify this token on every request. If you are using
web browser app you can use server-side sessions for authorization (
Its much more easier).
So my propose is to keep the authorization logic in the Controller.
I'll use Rails as an example. The authorization library, pundit, places authorization firmly within the "model" domain - this is enforced through their helper methods.
Suppose you have a ShoppingBag model. You might want to create a ShoppingBag
class ShoppingBagController
def create
authorize ShoppingBag.new, current_user
end
end
It works really well if you have a 1-1 mapping between a model and a controller. But what if you need a second controller on the same model? Now you're stuck!
class DiscountedShoppingBagController
def create
authorize ShoppingBag.new, current_user # does not work for us. we want a slightly different authorization, on the same model.
end
end
It's for that reason I dislike pundit, and CanCanCan. Authorization at the controller level, for me, is ideal. Doing so on the model level limits me too much, without any commensurate gain.