Current Model in Proposal Provider - xtext

I try to check the spelling and make dynamic proposals based on previous inputs.
For checking the spelling I use the Validator and code like this.
#Check
def checkUniqueDeclarations(Model model) {
for (decl : model.declarations) {
if (decl instanceof Device) {
for(input : decl.input)
...
In this code I have a Model which does exactly what I want.
But for making dynamic proposal I need to use the proposal provider in the ui project.
Can someone explain me how to get the same Model in the proposal provider as in the Validator? So I can use a similar code there.
Thank you

The model can be obtained from the given ContentAssistContext. You may need to navigate to the eContainer of the correct type. Please try to use EcoreUtil2.getContainerOfType for that purpose.

Related

Including Domain Object Security #PostFilter in Spring Data repositories Pageable endpoints

In my project I use Spring-Data, Spring-Data-Rest and Spring-Security.
What I need to accomplish is to implement domain object security (ACL) over these repositories. Specificaly #PostFilter over Pageable.findAll() method.
Method level security is easily implemented as outlined here.
There is also a section in docs about using security expression with #Query here.
But although I can use hasPermission(..) method inside #Query too, there is no way to include the object (SQL row) in this method - to be specific do this:
#Query("select u from #{#entityName} u where 1 = ?#{security.hasPermission(u, 'read') ? 1 : 0}")
Now I understand that this is way different than modifying the query pre-execution like this:
#Query("select m from Message m where m.to.id = ?#{ principal?.id }")
I also found the following jira issue:
https://jira.spring.io/browse/DATACMNS-293
Which I suspect that once it gets resolved there will be a solution to this, but it doesn't seem like it's going to be anytime soon.
I still need to implement this functionality and for that I would like to get your input and pointers on possible solutions.
Right now I am thinking about creating my custom annotation that will mimmick the #PostFilter one and use the same syntax but will get invoked manually inside my own BaseRepositoryImplementation. There I will get the repository interface from type and Repositories#getRepositoryInformationFor(type)#getRepositoryInterface(), find the annotation on respective method and manually invoke the security check.
Do you maybe have a different solution, or some notes about my proposed solution?
Also do you happen to know if there is any timetable on the mentioned jira issue?
One lightweight way is to do it is using the hasPermission() method and implementing your own "Permission Evaluator" at the Controller level, if that's an option for you.
#PreAuthorize("hasPermission(#employee, 'edit')")
public void editEmployee(Employee employee) {
...
}
#Component
public class PermissionEvaluatorImpl implements PermissionEvaluator {
#Override
public boolean hasPermission(Authentication auth,
Object targetDomainObject, Object permission) {
// return true if "auth" has "permission" permission for the user.
// Current-user can be obtained from auth.
}
...
}
This is described in more detail here: http://www.naturalprogrammer.com/spring-domain-object-security-logged-in-user/

.NET MVC preventing forged POST

SITUATION:
I have a Model and based on a users Role I want to allow the user to only update certain parts of the model. Lets say the Model has three fields. (My Model is obviously more complex than this)
MyObject
Field1
Field2
Field3
My View looks something like this:
Html.TextBoxFor(#Model.Field1)
Html.TextBoxFor(#Model.Field2)
#if(UserIsAdmin())
Html.TextBoxFor(#Model.Field3)
else
#Model.Field3
Bearing with me on the syntax (and the poor design of the example), you can see what I'm trying to do. Upon the user posting the form my controller would just take the MyObject and save it back to the database, we are using EF.
QUESTION:
My question is, is there a way to stop a user from forging a POST to be able to save data he/she should not be able to. My current idea would be to do a check in the controller to see if the user modified values he should not have. Or I could save fields individually, but neither is a convient solution.
Is there a better one?
Thanks!
Additional Info:
Not sure if this artical is relevant at all: http://blog.stevensanderson.com/2008/09/01/prevent-cross-site-request-forgery-csrf-using-aspnet-mvcs-antiforgerytoken-helper/
All three fields are from the same database table and I'm using EF to get and save the entity.
You want to make sure the user is only able to update permitted fields.
You decided that the way to achieve this is to prevent the user "forging" a response using e.g. firebug, or F12 developer tools, or GreaseMonkey, and have asked how to do this.
But the correct/best method is to check which fields the user is attempting to update, and only update those which he is permitted to update. Then it doesn't matter if they forge the request or not, they still won't be able to access anything they shouldn't. In other words, check access rights at the point of access.
Anti-forgery tokens are there to solve a separate problem, namely XSRF.
Use a viewmodel that accepts only the fields that should be updated and then populate the model with those values. You could use something like AutoMapper for mapping between the two.
My current idea would be to do a check in the controller to see if the user modified values he should not have. Or I could save fields individually, but neither is a convient solution.
You're on the right track with that idea. A typical Add() operation would look like this:
public class FooController : Controller
{
public ActionResult Add(FooViewModel viewModel)
{
if (ModelState.IsValid)
{
FooDataModel dataModel = FooMapper.MapToDataModel(viewModel, User);
FooRepository.Add(dataModel);
}
}
}
Like #VimalStan said, your FooViewModel is then a model that contains only the fields you want to let the user update. Also this still doesn't solve your problem, which should be done in your mapper (in this case FooMapper) and still check every field as #Ben suggested:
public static class FooMapper
{
public static FooDataModel Map(FooViewModel viewModel, IPrincipal user)
{
var dataModel = new FooDataModel();
dataModel.Field1 = viewModel.Field1;
dataModel.Field2 = viewModel.Field2;
if (IsAllowedToUpdateField3(user))
{
dataModel.Field3 = viewModel.Field3;
}
return dataModel;
}
public static bool IsAllowedToUpdateField3(IPrincipal user)
{
return false; // your logic
}
}

symfony 1.4 - inject current logged in user into Doctrine model

I would like to inject, with full testability, the id of the current logged in user into a creator_id field of a Doctrine_Record class, without using the sfContext singleton. I found a couple of Doctrine behaviours like http://www.symfony-project.org/plugins/sfDoctrineActAsSignablePlugin, but they access the sfContext singleton in a listener or (in another example I found) in the save method of a subclass of Doctrine_Record.
I want to find a single entry point in the symfony controller, where I can inject the current logged in user and keep it till the end of the request.
How do I do?
Hope I have been clear enough.
EDIT:
As #jeremy suggested, I made a custom filter:
class userFilter extends sfFilter
{
public function execute($filterChain)
{
$user = $this->getContext()->getUser();
if ($user->isAuthenticated()) {
$guard = $user->getGuardUser();
Doctrine_Manager::getInstance()->setAttribute('logged_in_user', $guard->getId());
}
// Execute next filter
$filterChain->execute();
}
}
So now my tests and my tasks are sfContext free, I just have to set the proper user Id at some point before starting the interactions with the db:
Doctrine_Manager::getInstance()->setAttribute('logged_in_user', sfConfig::get('default_user'));
Great question! The use of sfContext everywhere is one of the uglier aspects of Symfony 1 and setting it on Doctrine_Manager sounds like a solid idea.
It's probably best to do this either in the configureDoctrine callback that happens in ProjectConfiguration (see below). I'm not 100% a user is present at this point, if it's not, your best bet is a custom filter (reference).
public function configureDoctrine(Doctrine_Manager $manager)
{
$manager->setParam('user_id', sfContext::getInstance()->getUser()->getGuardUser()->getId());
}
Thanks for raising this question. I wrote the http://www.symfony-project.org/plugins/sfAuditablePlugin with this in mind. I basically externalized the method that returns the userId so you can get the userId from session, doctrine parameter or wherever you have it.
Here are the settings to configure the method that returns an array containing user_id and user_name
# Retrieve User Array from custom implementation
# [0] => (int)user_id; [1] => (string)user_name;
getUserArray:
class_name: Utility
static_method_name: getUserAuditArray

Grails Plugins Requiring External Relationships

I posted this on the Grails mailing list yesterday and haven't had any hits. Figured I'd try here as well today.
I'm considering writing a grails plugin but this plugin would require some sort of relationship to an account / user object. However, I don't want to force a particular security model on the plugin. For example, say was writing a comment system plugin (I'm not). I'd have a comment object...
class Comment {
String comment
Date dateCreated
// etc etc
}
The comment is missing a couple of things:
Who added the comment
What the comment was added to.
I'd like to first focus on #1. So someone might be using the Spring security plugin and use the default Person object, or maybe they changed that to User. Who knows. Is there any way that anyone can think of to configure that relationship without hard coding it in the plugin?
One thing I've thought about was to have the grails app extend the plugin's domain classes to add this relationship. so I might do something like...
class ArticleComment extends Comment {
static belongsTo = [user:User]
}
But in a larger plugin, that might be a lot of inheritance requirements. Not the end of the world, but just looking for other possible options.
You can use the same technique employed by the Commentable plugin:
The user of your plugin will need to declare a closure in Config.groovy to evaluate the logged user:
grails.myplugin.user.evaluator = { session.user }
And you can use something like this in your plugin's code to call the user configured closure:
def evaluateUser() {
def evaluator = grailsApplication.config.grails.myplugin.user.evaluator
def user
if(evaluator instanceof Closure) {
evaluator.delegate = this
evaluator.resolveStrategy = Closure.DELEGATE_ONLY
user = evaluator.call()
}
if(!user) {
throw new Exception("No [grails.myplugin.user.evaluator] setting defined or the evaluator doesn't evaluate to an entity. Please define the evaluator correctly in grails-app/conf/Config.groovy")
}
if(!user.id) {
throw new Exception("The evaluated user is not a persistent instance.")
}
return user
}
I think you can do it like SpringSecurity do. Instead of let people extend your Comment class, You can write 2 class CommentUser & CommentPlace; then let others extends them. I think it's more simple.

MVC2: Validating User Input / Best Practices

I'm trying to validate user input, in particular user passwords. I have some jQuery validation, but of course I also need to validate on the server side. Now my request comes in to the controller, which will hand it off to a UserService. Everything is loosely coupled, so the controller really doesn't know too much about the inner UserService. Now suppose the user entered a weak password so I need to tell him "hey, that is insufficient."
Question is: What is the best way to do this?
Somehow, I need to be able to call
ModelState.AddModelError(field, exception);
in order to indicate what went wrong, where and why - in the simple example I already know it's the password because it is really the only field on the form, but in general this is not so easy. Now I was close to writing my own Exception type to do something like
ModelState.AddModelError(ex.Field, ex.Message);, where I might need some additional mapping - which is essentiale the path taken in NerdDinner where they have RuleViolations.
However, in NerdDinner, the business object is self-validating. This doesn't seem to be the best way in this case, because the 'business object' here is really just a store for email and password that implements IIdentity. It shouldn't know anything about password lengths and should be reusable across different applications.
Moreover, ArgumentException and ValidationException don't seem to fit either because the first is made for contract violations and the latter is to be used by DataAnnotations.
All this is just the tip of an iceberg of course, because there are so many subtleties lurking around. Perhaps someone can point me in the right direction?
You can use xVal.
If I understand correctly you want to validate whether the user password is sufficient or insufficient. If you aren't using self validation on the object itself then can I suggest you put a validation method on your user service.
...
var result = userService.Validate(newUser);
if (!result.IsValid) {
result.Errors.ForEach( m => ModelState.AddModelError(m.field, m.message));
}
...
How about that?
The only issue with this approach is that to access any validation around the User object you'd have to pass it into the userService, which may or may not be what you want to do.
Answer to comment below:
Well you would have to create a ValidationResult, something like.
public class ValidationResult
{
public string Field {get;set;}
public string Message {get;set;}
}
So if I'm reading correctly, your Controller has a UserService, the UserService has a Validator, and the Validator validate the User.
As you pass this validation up from your Validator to UserService to Controller, just intercept it and use it, then pass it along.
If you don't want to role your own validation library (and you shouldn't) there are some great tools like Enterprise Library and FluentValidation. They can separately define your validation logic external of your objects if that is what you are concerned about.

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