/// <summary>
/// Core logic for applying the query option to the IQueryable.
/// </summary>
/// <param name="query">The original <see cref="IQueryable"/>.</param>
/// <param name="querySettings">Query setting used for validating the query option.</param>
/// <param name="orderByNodes">OrderBy information required to correctly apply the query option for default implementation.</param>
/// <param name="context">The <see cref="ODataQueryContext"/> which contains the <see cref="IEdmModel"/> and some type information</param>
/// <param name="skipTokenRawValue">The raw string value of the skiptoken query parameter.</param>
/// <returns></returns>
private static IQueryable ApplyToCore(IQueryable query, ODataQuerySettings querySettings, IList <OrderByNode> orderByNodes, ODataQueryContext context, string skipTokenRawValue)
{
if (query == null)
{
throw Error.ArgumentNull(nameof(query));
}
if (context.ElementClrType == null)
{
throw Error.NotSupported(SRResources.ApplyToOnUntypedQueryOption, "ApplyTo");
}
IDictionary <string, OrderByDirection> directionMap;
if (orderByNodes != null)
{
directionMap =
orderByNodes.OfType <OrderByPropertyNode>().ToDictionary(node => node.Property.Name, node => node.Direction);
}
else
{
directionMap = new Dictionary <string, OrderByDirection>();
}
IDictionary <string, object> propertyValuePairs = PopulatePropertyValuePairs(skipTokenRawValue, context);
if (propertyValuePairs.Count == 0)
{
throw Error.InvalidOperation("Unable to get property values from the skiptoken value.");
}
ExpressionBinderBase binder = new FilterBinder(context.RequestContainer);
bool parameterizeConstant = querySettings.EnableConstantParameterization;
ParameterExpression param = Expression.Parameter(context.ElementClrType);
Expression where = null;
/* We will create a where lambda of the following form -
* Where (Prop1>Value1)
* OR (Prop1=Value1 AND Prop2>Value2)
* OR (Prop1=Value1 AND Prop2=Value2 AND Prop3>Value3)
* and so on...
* Adding the first true to simplify implementation.
*/
Expression lastEquality = null;
bool firstProperty = true;
foreach (KeyValuePair <string, object> item in propertyValuePairs)
{
string key = item.Key;
MemberExpression property = Expression.Property(param, key);
object value = item.Value;
Expression compare = null;
ODataEnumValue enumValue = value as ODataEnumValue;
if (enumValue != null)
{
value = enumValue.Value;
}
Expression constant = parameterizeConstant ? LinqParameterContainer.Parameterize(value.GetType(), value) : Expression.Constant(value);
if (directionMap.ContainsKey(key) && directionMap[key] == OrderByDirection.Descending)
{
compare = binder.CreateBinaryExpression(BinaryOperatorKind.LessThan, property, constant, true);
}
else
{
compare = binder.CreateBinaryExpression(BinaryOperatorKind.GreaterThan, property, constant, true);
}
if (firstProperty)
{
lastEquality = binder.CreateBinaryExpression(BinaryOperatorKind.Equal, property, constant, true);
where = compare;
firstProperty = false;
}
else
{
Expression condition = Expression.AndAlso(lastEquality, compare);
where = Expression.OrElse(where, condition);
lastEquality = Expression.AndAlso(lastEquality, binder.CreateBinaryExpression(BinaryOperatorKind.Equal, property, constant, true));
}
}
Expression whereLambda = Expression.Lambda(where, param);
return(ExpressionHelpers.Where(query, whereLambda, query.ElementType));
}
private IOrderedQueryable ApplyToCore(IQueryable query, ODataQuerySettings querySettings)
{
if (Context.ElementClrType == null)
{
throw Error.NotSupported(SRResources.ApplyToOnUntypedQueryOption, "ApplyTo");
}
ICollection <OrderByNode> nodes = OrderByNodes;
bool alreadyOrdered = false;
IQueryable querySoFar = query;
HashSet <IEdmProperty> propertiesSoFar = new HashSet <IEdmProperty>();
HashSet <string> openPropertiesSoFar = new HashSet <string>();
bool orderByItSeen = false;
foreach (OrderByNode node in nodes)
{
OrderByPropertyNode propertyNode = node as OrderByPropertyNode;
OrderByOpenPropertyNode openPropertyNode = node as OrderByOpenPropertyNode;
if (propertyNode != null)
{
IEdmProperty property = propertyNode.Property;
OrderByDirection direction = propertyNode.Direction;
// This check prevents queries with duplicate properties (e.g. $orderby=Id,Id,Id,Id...) from causing stack overflows
if (propertiesSoFar.Contains(property))
{
throw new ODataException(Error.Format(SRResources.OrderByDuplicateProperty, property.Name));
}
propertiesSoFar.Add(property);
if (propertyNode.OrderByClause != null)
{
querySoFar = AddOrderByQueryForProperty(query, querySettings, propertyNode.OrderByClause, querySoFar, direction, alreadyOrdered);
}
else
{
querySoFar = ExpressionHelpers.OrderByProperty(querySoFar, Context.Model, property, direction, Context.ElementClrType, alreadyOrdered);
}
alreadyOrdered = true;
}
else if (openPropertyNode != null)
{
// This check prevents queries with duplicate properties (e.g. $orderby=Id,Id,Id,Id...) from causing stack overflows
if (openPropertiesSoFar.Contains(openPropertyNode.PropertyName))
{
throw new ODataException(Error.Format(SRResources.OrderByDuplicateProperty, openPropertyNode.PropertyName));
}
openPropertiesSoFar.Add(openPropertyNode.PropertyName);
Contract.Assert(openPropertyNode.OrderByClause != null);
querySoFar = AddOrderByQueryForProperty(query, querySettings, openPropertyNode.OrderByClause, querySoFar, openPropertyNode.Direction, alreadyOrdered);
alreadyOrdered = true;
}
else
{
// This check prevents queries with duplicate nodes (e.g. $orderby=$it,$it,$it,$it...) from causing stack overflows
if (orderByItSeen)
{
throw new ODataException(Error.Format(SRResources.OrderByDuplicateIt));
}
querySoFar = ExpressionHelpers.OrderByIt(querySoFar, node.Direction, Context.ElementClrType, alreadyOrdered);
alreadyOrdered = true;
orderByItSeen = true;
}
}
return(querySoFar as IOrderedQueryable);
}
/// <summary>
/// Apply the individual query to the given IQueryable in the right order.
/// </summary>
/// <param name="query">The original <see cref="IQueryable"/>.</param>
/// <param name="querySettings">The settings to use in query composition.</param>
/// <param name="pageSize">The page size for this query</param>
/// <returns>The new <see cref="IQueryable"/> after the query has been applied to.</returns>
public virtual IQueryable ApplyTo(IQueryable query, ODataQuerySettings querySettings, int?pageSize)
{
if (query == null)
{
throw Error.ArgumentNull("query");
}
// Construct the actual query and apply them in the following order: filter
if (Filter != null)
{
query = Filter.ApplyTo(query, querySettings, _assemblyProvider);
}
var orderBy = OrderBy;
// $skip or $top require a stable sort for predictable results.
// Result limits require a stable sort to be able to generate a next page link.
// If either is present in the query and we have permission,
// generate an $orderby that will produce a stable sort.
if (querySettings.EnsureStableOrdering &&
(Skip != null ||
Top != null ||
pageSize.HasValue))
{
// If there is no OrderBy present, we manufacture a default.
// If an OrderBy is already present, we add any missing
// properties necessary to make a stable sort.
// Instead of failing early here if we cannot generate the OrderBy,
// let the IQueryable backend fail (if it has to).
orderBy = orderBy == null
? OrderByHelper.GenerateDefaultOrderBy(Context, _serviceProvider)
: OrderByHelper.EnsureStableSortOrderBy(orderBy, Context, _serviceProvider);
}
// First apply $apply
// Section 3.15 of the spec http://docs.oasis-open.org/odata/odata-data-aggregation-ext/v4.0/cs01/odata-data-aggregation-ext-v4.0-cs01.html#_Toc378326311
if (Apply != null)
{
query = Apply.ApplyTo(query, querySettings, _assemblyProvider);
Request.ODataFeature().ApplyClause = Apply.ApplyClause;
Context.ElementClrType = Apply.ResultClrType;
}
if (orderBy != null)
{
query = orderBy.ApplyTo(query, querySettings);
}
if (Skip.HasValue)
{
query = ExpressionHelpers.Skip(query, Skip.Value, Context.ElementClrType, false);
}
int?take = null;
if (querySettings.PageSize.HasValue)
{
take = Math.Min(querySettings.PageSize.Value, int.MaxValue);
}
if (Top.HasValue)
{
take = Math.Min(Top.Value, take ?? int.MaxValue);
}
if (take.HasValue)
{
query = ExpressionHelpers.Take(query, take.Value, Context.ElementClrType, false);
}
if (SelectExpand != null)
{
query = SelectExpand.ApplyTo(query, querySettings, _assemblyProvider);
}
if (CountQueryOption != null)
{
if (Request.ODataFeature().TotalCountFunc == null)
{
Func <long> countFunc = CountQueryOption.GetEntityCountFunc(query);
if (countFunc != null)
{
Request.ODataFeature().TotalCountFunc = countFunc;
}
}
if (ODataCountMediaTypeMapping.IsCountRequest(Request.HttpContext))
{
return(query);
}
}
if (pageSize.HasValue)
{
bool resultsLimited;
query = LimitResults(query, pageSize.Value, out resultsLimited);
if (resultsLimited && Request.GetDisplayUrl() != null && new Uri(Request.GetDisplayUrl()).IsAbsoluteUri&& Request.ODataFeature().NextLink == null)
{
Uri nextPageLink = Request.GetNextPageLink(pageSize.Value);
Request.ODataFeature().NextLink = nextPageLink;
}
}
return(query);
}
