/// <inheritdoc/>
protected override void BuildRenderTree(RenderTreeBuilder builder)
{
if (Source == null)
{
WhenNull?.Invoke(builder);
return;
}
var componentType = MatchingTypeFinder.TryFind(Source.GetType(), Scope);
if (componentType == null)
{
if (WhenNoMatchFound == null)
{
throw Errors.NoMatchingComponentFound(Source.GetType(), Scope);
}
WhenNoMatchFound(Source)(builder);
return;
}
var i = 0;
builder.OpenComponent(i++, componentType);
if (!string.IsNullOrEmpty(SourceParameterName))
{
builder.AddAttribute(i++, SourceParameterName, Source);
}
if (Attributes != null)
{
foreach (var(key, value) in Attributes)
{
builder.AddAttribute(i++, key, value);
}
}
builder.CloseComponent();
}
/// <summary>
/// Secures an entity by an enumerable property.
/// </summary>
/// <typeparam name="TK">The type to secure by.</typeparam>
/// <typeparam name="TId">The type of the IDs to secure by.</typeparam>
/// <param name="pathToCollection">An expression representing the path from an instance of T to the property of Type TK that T should be by.</param>
/// <param name="whenNull">The behaviour to use when entitlements are null.</param>
/// <returns>A Relationship representing how T should be by TK.</returns>
public SecuredRelationship ByCollection <TK, TId>(Expression <Func <T, IEnumerable <TK> > > pathToCollection, WhenNull whenNull)
where TK : IIdentifiable <TId>
where TId : IEquatable <TId>
{
var closuredLambdaBuilder = PredicateBuilder.BuildPredicateFactoryForCollectionProperty <T, TK, TId>(pathToCollection, whenNull);
return(new SecuredRelationship(typeof(T), typeof(IEnumerable <TK>), closuredLambdaBuilder.Compile()));
}
public static LambdaExpression BuildPredicateFactoryForCollectionProperty(Type rootType, Type typeInCollection, Type keyType, LambdaExpression pathToRelationship, WhenNull whenNull)
{
// We are building one of the below expression factories
// ids => return x => !x.CollectionProperty.Any() || x.CollectionProperty.Any(c => ids.Contains(c.Id))
// ids => return x => x.CollectionProperty.Any() && x.CollectionProperty.Any(c => ids.Contains(c.Id))
// Create the constructed generic type of Func<T, bool> without having access to a generic parameter of T ( the parameter rootType is the result of typeof(T) )
var typeForRootPredicate = MakeFuncOfTBool(rootType);
// Create a parameter that represents the object from the collection, this will later become the {parameter of typeInCollection} => part of a lambda
var parameterForSingleId = Expression.Parameter(typeInCollection);
// Create an Expression to turn the parameter into an accessor like {parameter of typeInCollection}.Id, when combined in a lambda this will become {parameter of typeInCollection} => {parameter of typeInCollection}.Id
var accessorForSingleId = Expression.PropertyOrField(parameterForSingleId, "Id");
// Reflect the generic method information from the keyType for checking later. This will be IEnumberable<keyType>.Contains({parameter of keyType})
var containsMethod = MakeContainsMethod(keyType, 2);
// Create a parameter that represents the type of list of Ids that your user is entitled to access, this is IEnumerable<keyType>
var typeForEntitledIdsParameter = MakeEnumerableOfT(keyType);
// Create a parameter that represents the list of Ids that your user is entitled to access, created from the above type
var parameterForEntitledIds = MakeIdsParameter(typeForEntitledIdsParameter);
// Reflect LINQ methods to get the .Any() and .Any(x => [lambda predicate here]) methods
var reflectedMethodInfoForLinqAnyThatDoesNotTakeParameters = MakeAnyMethod(typeInCollection, 1);
var reflectedMethodInfoForLinqAnyThatTakesAPredicate = MakeAnyMethod(typeInCollection, 2);
// Create an expression that given a collection of Ids calls contains, and passes the Id accessor from above. Outputs - ids.Contains({parameter of typeInCollection}.Id)
var containsMethodCall = Expression.Call(null, containsMethod, parameterForEntitledIds, accessorForSingleId);
// Create a lambda from the above method call that closures in a reference to the type in collection. Outputs - {parameter of typeInCollection} => ids.Contains({parameter of typeInCollection}.Id)
var containsPredicate = Expression.Lambda(containsMethodCall, parameterForSingleId);
// Create a placeholder for variations of which where predicate we are going to need based on null behavior.
Expression wherePredicate;
switch (whenNull)
{
// When we find a null object, the security expression should treat this the same as finding an object the user has permissions to
case WhenNull.Allow:
{
// Build the follow predicate x => !x.CollectionProperty.Any() || x.CollectionProperty.Any(c => ids.Contains(c.Id))
wherePredicate = BuildAllowWhenNullWherePredicate(pathToRelationship, typeForRootPredicate, reflectedMethodInfoForLinqAnyThatTakesAPredicate, reflectedMethodInfoForLinqAnyThatDoesNotTakeParameters, containsPredicate);
}
break;
// When we find a null object, the security expression should treat this the same as finding an object that the user doesn't have permission to
case WhenNull.Deny:
{
// Build the following predicate x => x.CollectionProperty.Any() && x.CollectionProperty.Any(c => ids.Contains(c.Id))
wherePredicate = BuildDenyWhenNullWherePredicate(pathToRelationship, typeForRootPredicate, reflectedMethodInfoForLinqAnyThatDoesNotTakeParameters, reflectedMethodInfoForLinqAnyThatTakesAPredicate, containsPredicate);
}
break;
default:
{
throw new NotImplementedException("Allow and Deny are the only supported behaviors. Stop modifying the enum without fixing the expression generator too!!");
}
}
// Return a expression that when compiled will build a where predicate on execution. ids => { predicate that takes ids from above }
return(Expression.Lambda(Expression.Quote(wherePredicate), parameterForEntitledIds));
}
public static LambdaExpression BuildPredicateFactoryForCollectionProperty <T, TK, TId>(Expression <Func <T, IEnumerable <TK> > > pathToRelationship, WhenNull whenNull)
where TK : IIdentifiable <TId>
where TId : IEquatable <TId>
{
return(BuildPredicateFactoryForCollectionProperty(typeof(T), typeof(TK), typeof(TId), pathToRelationship, whenNull));
}
public static LambdaExpression BuildPredicateFactoryForSingleProperty(Type rootType, Type typeInProperty, Type keyType, LambdaExpression pathToRelationship, WhenNull whenNull)
{
// We are building one of the below expression factories
// ids => return x => x.SingleProperty == null || ids.Contains(x.SingleProperty.Id)
// ids => return x => ids.Contains(x.SingleProperty.Id)
// Create the constructed generic type of Func<T, bool> without having access to a generic parameter of T ( the parameter rootType is the result of typeof(T) )
var typeForRootPredicate = MakeFuncOfTBool(rootType);
// Create an Expression to turn the parameter into an accessor like {parameter of rootType}.SingleProperty.Id, when combined in a lambda this will become {parameter of rootType} => {parameter of rootType}.SingleProperty.Id
var accessorForSingleId = Expression.PropertyOrField(pathToRelationship.Body, "Id");
// Create a parameter that represents the type of list of Ids that your user is entitled to access, this is IEnumerable<keyType>
var typeForEntitledIdsParameter = MakeEnumerableOfT(keyType);
// Create a parameter that represents the of list of Ids that your user is entitled to access, created from the above type
var parameterForEntitledIds = MakeIdsParameter(typeForEntitledIdsParameter);
// Reflect the generic method infromation from the keyType for checking later. This will be IEnumberable<keyType>.Contains({parameter of keyType})
var containsMethod = MakeContainsMethod(keyType, 2);
// Create an expression that given a collection of Ids calls contains, and passes the Id accessor from above. Outputs - ids.Contains({parameter of rootType}.Id)
var containsMethodCall = Expression.Call(null, containsMethod, parameterForEntitledIds, accessorForSingleId);
// Create a placeholder for variations of which where predicate we are going to need based on null behavior.
Expression wherePredicate;
switch (whenNull)
{
// When we find a null object, the security expression should treat this the same as finding an object the user has permissions to
case WhenNull.Allow:
{
// Create a check for property = null and add it in an or to the lambda
var nullCheckOnProp = Expression.Equal(pathToRelationship.Body, Expression.Constant(null, typeInProperty));
// Create the lambda ( x => x.SingleProperty == null || ids.Contains(x.SingleProperty.Id) )
wherePredicate = Expression.Lambda(typeForRootPredicate, Expression.OrElse(nullCheckOnProp, containsMethodCall), pathToRelationship.Parameters);
}
break;
// When we find a null object, the security expression should treat this the same as finding an object that the user doesn't have permission to
case WhenNull.Deny:
{
// Create the lambda ( x => ids.Contains(x.SingleProperty.Id) )
wherePredicate = Expression.Lambda(typeForRootPredicate, containsMethodCall, pathToRelationship.Parameters);
}
break;
default:
{
throw new NotImplementedException("Allow and Deny are the only supported behaviors, stop modifying the enum without fixing the expression generator too!!");
}
}
// Return a expression that when compiled will build a where predicate on execution. ids => { predicate that takes ids from above }
return(Expression.Lambda(Expression.Quote(wherePredicate), parameterForEntitledIds));
}
